CSCI 3335: C OMPUTER N ETWORKS C HAPTER 3 T RANSPORT L AYER Vamsi Paruchuri University of Central...

CSCI 3335 COMPUTER NETWORKS

CHAPTER 3 TRANSPORT LAYER

Vamsi ParuchuriUniversity of Central Arkansas

httpfacultyucaeduvparuchuri3335htm

Some of the material is adapted from JF Kurose and KW Ross

Transport Layer 3-2

Chapter 3 outline

31 Transport-layer services32 Multiplexing and demultiplexing33 Connectionless transport UDP34 Principles of reliable data transfer

35 Connection-oriented transport TCP segment structure reliable data transfer flow control connection

management

36 Principles of congestion control

37 TCP congestion control

Transport Layer 3-3

TCP Overview RFCs 793 1122 1323 2018 2581

full duplex data bi-directional data flow

in same connection MSS maximum

segment size connection-oriented

handshaking (exchange of control msgs) inits sender receiver state before data exchange

flow controlled sender will not

overwhelm receiver

point-to-point one sender one

receiver reliable in-order byte

steam no ldquomessage

boundariesrdquo pipelined

TCP congestion and flow control set window size

send amp receive buffers

socketdoor

T C Psend buffer

T C Preceive buffer

socketdoor

segm ent

applicationwrites data

applicationreads data

Transport Layer 3-4

TCP segment structure

source port dest port

32 bits

applicationdata

(variable length)

sequence number

acknowledgement numberReceive window

Urg data pnterchecksum

FSRPAUheadlen

notused

Options (variable length)

URG urgent data (generally not used)

ACK ACK valid

PSH push data now(generally not used)

RST SYN FINconnection estab(setup teardown

commands)

bytes rcvr willingto accept

countingby bytes of data(not segments)

Internetchecksum

(as in UDP)

Transport Layer 3-5

TCP segment structure - Quiz


32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused


What is the significance of each fieldWhat is TCP Header sizeWhat is max Receiver Window Size

Is it large enoughWhich field should be larger ldquoSeqrdquo

or ldquoReceive windowrdquo WhyWhat is the maximum optionsWhich flags are set in first message

in connection set up Second message Third message

Why are initial Seq set randomly

Flags SYN FIN RESET PUSH URG ACK

TCP Header Flags (6 bits)

Connection establishmenttermination SYN ndash establish sequence number field

contains valid initial sequence number FIN - terminate

RESET - abort connection because one side received something unexpected

PUSH - sender invoked push to send URG ndash indicated urgent pointer field is

valid special data - record boundary ACK - indicates Acknowledgement field

is valid

3 Transport Layer 3b-6

TCP Header ACK flag

ACK flag ndash if on then acknowledgement field valid

Once connection established no reason to turn off Acknowledgment field is always in header

so acknowledgements are free to send along with data


TCP Header PUSH

Intention use to indicate not to leave the data in a TCP buffer waiting for more data before it is sent

Receiver is supposed to interpret as deliver to application immediately most TCPIP implementations donrsquot delay delivery in the first place though


TCP Header Header Length Header Length (4 bits)

needed because options field make header variable length

Expressed in number of 32 bit words = 4 bytes

4 bits field =gt 4 bytes24 = 60 bytes 20 bytes of required header gives 40 bytes possible of options

Recall UDP header was 8 bytes



32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused


Implications of Field Length

32 bits for sequence number (and acknowledgement) 16 bits for advertised window size

Implication for maximum window size Window size lt= frac12 SequenceNumberSpace Requirement easily satisfied because

receiver advertised window field is 16 bitsbull 232 gtgt 2 216

bull Even if increase possible advertised window to 231

that would still be ok


Implications of Field Length (cont)Advertised Window is 16 bit field

=gt maximum window is 64 KB Is this enough to fill the pipeline Not

always Pipeline = delayBW product 100 ms roundtrip and 100 Mbps =gt

119 MB


TCP Header Common Options Options used to extend and test TCP Each option is

1 byte of option kind 1 byte of option length

Examples window scale factor if donrsquot want to be limited to 216

bytes in receiver advertised window timestamp option if 32 bit sequence number space

will wrap in MSL add 32 bit timestamp to distinguish between two segments with the same sequence number

Maximum Segment Size can be set in SYN packets


TCP Connection Management

Recall TCP sender receiver establish ldquoconnectionrdquo before exchanging data segments

initialize TCP variables seq s buffers flow control

info (eg RcvWindow) client connection

initiator Socket clientSocket = new

Socket(hostnameport

number) server contacted by

client Socket connectionSocket =

welcomeSocketaccept()

Three way handshake

Step 1 client end system sends TCP SYN control segment to server specifies initial seq

Step 2 server end system receives SYN replies with SYNACK control segment ACKs received SYN allocates buffers specifies server-gt

receiver initial seq

Step 3 client acknowledges servers initial seq


Three-Way Handshake


Active participant(client)

Passive participant(server)

SYN SequenceNum = x

SYN + ACK SequenceNum = y

ACK Acknowledgment = y + 1

Acknowledgment = x + 1

SequenceNum = x+1

Connection Establishment

Both data channels opened at once Three-way handshake used to agree on a

set of parameters for this communication channel Initial sequence number for both sides

(random) Receiver advertised window size for both

sides Optionally Maximum Segment Size (MSS) for

each side if not specified MSS of 536 bytes is assumed to fit into 576 byte datagram


Initial Sequence Numbers

Chosen at random in the sequence number space

Well not really randomly intention of RFC is for initial sequence numbers to change over time 32 bit counter incrementing every 4

microseconds Vary initial sequence number to avoid

packets that are delayed in network from being delivered later and interpreted as a part of a newly established connection (to avoid reincarnations) 3 Transport Layer 3b-16

Transport Layer 3-17

TCP seq rsquos and ACKsSeq rsquos

byte stream ldquonumberrdquo of first byte in segmentrsquos data

ACKs seq of next

byte expected from other side

cumulative ACKQ how receiver

handles out-of-order segments A TCP spec

doesnrsquot say - up to implementor

Host A Host B

Seq=42 ACK=79 data = lsquoCrsquo


Seq=43 ACK=80

Usertypes

lsquoCrsquo

host ACKsreceipt

of echoedlsquoCrsquo

host ACKsreceipt of

lsquoCrsquo echoesback lsquoCrsquo

timesimple telnet scenario

Connection Termination

Each side of the bi-directional connection may be closed independently 4 messages FIN message and ACK of that

FIN in each direction Each side closes the data channel it can

send on One side can be closed and data can

continue to flow in the other direction but not usually

FINs consume sequence numbers like SYNs 3 Transport Layer 3b-18

TCP Connection Management (cont)

Closing a connection

client closes socket clientSocketclose()

Step 1 client end system sends TCP FIN control segment to server

Step 2 server receives FIN replies with ACK Closes connection sends FIN


client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait


Chapter 3 outline



management




TCP reliable data transfer

TCP creates rdt service on top of IPrsquos unreliable service

pipelined segments cumulative acks TCP uses single retransmission timer

retransmissions are triggered by timeout events duplicate acks

initially consider simplified TCP sender ignore duplicate acks ignore flow control congestion control


TCP Quiz -2

What are ldquoCumulative Acksrdquo What is advantage of having short time outs What is advantage of having long time outs Describe the method(s) TCP uses to detect

packet losses What is Fast Retransmit


TCP sender eventsdata rcvd from app Create segment with

seq seq is byte-stream

number of first data byte in segment

start timer if not already running (think of timer as for oldest unacked segment)

expiration interval TimeOutInterval

timeout retransmit segment

that caused timeout restart timer Ack rcvd If acknowledges

previously unacked segments update what is known

to be acked start timer if there are

outstanding segments


TCP sender(simplified)

NextSeqNum = InitialSeqNum SendBase = InitialSeqNum

loop (forever) switch(event)

event data received from application above create TCP segment with sequence number NextSeqNum if (timer currently not running) start timer pass segment to IP NextSeqNum = NextSeqNum + length(data)

event timer timeout retransmit not-yet-acknowledged segment with smallest sequence number start timer

event ACK received with ACK field value of y if (y gt SendBase) SendBase = y if (there are currently not-yet-acknowledged segments) start timer

end of loop forever

Commentbull SendBase-1 last cumulatively acked byteExamplebull SendBase-1 = 71

y= 73 so the rcvrwants 73+ y gt SendBase sothat new data is acked

TCP retransmission scenarios

Host A

Seq=100 20 bytes data

ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100


TCP retransmission scenarios (more)

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

Cumulative ACK scenario

Host B

X


ACK=120

time

SendBase= 120


TCP Round Trip Time and TimeoutQ how to set TCP

timeout value longer than RTT

but RTT varies too short

premature timeout unnecessary

retransmissions too long slow

reaction to segment loss

Q how to estimate RTT SampleRTT measured time

from segment transmission until ACK receipt ignore retransmissions

SampleRTT will vary want estimated RTT ldquosmootherrdquo average several recent

measurements not just current SampleRTT


TCP Round Trip Time and TimeoutEstimatedRTT = (1- )EstimatedRTT + SampleRTT

Exponential weighted moving average influence of past sample decreases exponentially

fast typical value = 0125


Example RTT estimationRTT gaiacsumassedu to fantasiaeurecomfr

100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)

SampleRTT Estimated RTT


Fast Retransmit

time-out period often relatively long long delay before resending lost packet

detect lost segments via duplicate ACKs sender often sends many segments back-to-back if segment is lost there will likely be many duplicate

ACKs

if sender receives 3 ACKs for the same data it supposes that segment after ACKed data was lost fast retransmit resend

segment before timer expires


Host A

tim

eout

Host B

time

X

resend 2nd segment Seq=100 20 bytes data

Figure 337 Resending a segment after triple duplicate ACK

Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100

Seq=120 20 bytes dataSeq=140 20 bytes dataSeq=160 20 bytes data

ACK=180


Chapter 3 outline



management




TCP Flow Control

receive side of TCP connection has a receive buffer

speed-matching service matching the send rate to the receiving apprsquos drain rate

app process may be slow at reading from buffer

sender wonrsquot overflow

receiverrsquos buffer bytransmitting too

much too fast

flow control


TCP Flow control how it works

(suppose TCP receiver discards out-of-order segments)

spare room in buffer= RcvWindow= RcvBuffer-[LastByteRcvd -

LastByteRead]

rcvr advertises spare room by including value of RcvWindow in segments

sender limits unACKed data to RcvWindow guarantees receive

buffer doesnrsquot overflow


Chapter 3 outline



management









Socket(hostnameport




Three way handshake

Step 1 client host sends TCP SYN segment to server specifies initial seq no data

Step 2 server host receives SYN replies with SYNACK segment server allocates buffers specifies server initial

seq Step 3 client receives

SYNACK replies with ACK segment which may contain data







client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait



Step 3 client receives FIN replies with ACK

Enters ldquotimed waitrdquo - will respond with ACK to received FINs

Step 4 server receives ACK Connection closed

client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle

Quiz Why does TCP use time outs How does timeout impact the performance of TCP What are pros and cons for short (long) timeouts How is RTT estimated by TCP What is need for flow control in TCP Describe flow control mechanism What is the primary cause of congestion Mention 3 costs of congestion What is difference between flow and congestion

control



Chapter 3 outline



management




Principles of Congestion Control

Congestion informally ldquotoo many sources sending too

much data too fast for network to handlerdquo different from flow control manifestations

lost packets (buffer overflow at routers) long delays (queueing in router buffers)

a top-10 problem


Causescosts of congestion scenario 1

two senders two receivers

one router infinite buffers

no retransmission

large delays when congested

maximum achievable throughput

unlimited shared output link buffers

Host Alin original data

Host B

lout

lin original data

lout


Causescosts of congestion scenario 2 one router finite buffers sender retransmission of timed-out packet

application-layer input = application-layer output lin = lout

transport-layer input includes retransmissions lin lin

finite shared output link buffers

Host A

lin original data

Host B

loutlin original data plus

retransmitted data

lsquo


Congestion scenario 2a ideal case sender sends

only when router buffers available


Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space

packets may get dropped at router due to full buffers sometimes lost

sender only resends if packet known to be lost (admittedly idealized)

Congestion scenario 2b known loss



Host A

lin original data

Host B


retransmitted data

free buffer space

packets may get dropped at router due to full buffers sometimes not lost


R2

R2lin

l out

when sending at R2 some packets are retransmissions but asymptotic goodput is still R2


packets may get dropped at router due to full buffers

sender times out prematurely sending two copies both of which are delivered

Host A

lin

Host B

loutlincopy

free buffer space

Congestion scenario 2c duplicates

timeout

R4

R4lin

l out





ldquocostsrdquo of congestion more work (retrans) for given ldquogoodputrdquo unneeded retransmissions link carries multiple copies of

pkt decreasing goodput

R4

R4lin

l out


Causescosts of congestion scenario 3 four senders multihop paths timeoutretransmit

lin

Q what happens as and increase

lin



Host B

lout

lin original data plus retransmitted data



another ldquocostrdquo of congestion when packet dropped any ldquoupstream

transmission capacity used for that packet was wasted

Host A

Host B

lo

u

t


Approaches towards congestion control

end-end congestion control

no explicit feedback from network

congestion inferred from end-system observed loss delay

approach taken by TCP

network-assisted congestion control

routers provide feedback to end systems single bit indicating

congestion (SNA DECbit TCPIP ECN ATM)

explicit rate sender should send at

Two broad approaches towards congestion control


Chapter 3 outline



management




TCP congestion control additive increase multiplicative decrease

approach increase transmission rate (window size) probing for usable bandwidth until loss occurs additive increase increase cwnd by 1 MSS

every RTT until loss detected multiplicative decrease cut cwnd in half after

loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e

saw toothbehavior probing

for bandwidth


TCP Congestion Control details

sender limits transmission

LastByteSent-LastByteAcked cwnd roughly

cwnd is dynamic function of perceived network congestion

How does sender perceive congestion

loss event = timeout or 3 duplicate acks

TCP sender reduces rate (cwnd) after loss event

three mechanisms AIMD slow start conservative after

timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start

when connection begins increase rate exponentially until first loss event initially cwnd = 1 MSS double cwnd every RTT done by incrementing cwnd for every ACK received

summary initial rate is slow but ramps up exponentially fast

Host A

one segment

RTT

Host B

time

two segments

four segments


Refinement inferring loss

after 3 dup ACKs cwnd is cut in half window then grows

linearly but after timeout event

cwnd instead set to 1 MSS

window then grows exponentially

to a threshold then grows linearly

3 dup ACKs indicates network capable of delivering some segments

timeout indicates a ldquomore alarmingrdquo congestion scenario

Philosophy


Refinement

Q when should the exponential increase switch to linear

A when cwnd gets to 12 of its value before timeout

Implementation variable ssthresh on loss event ssthresh

is set to 12 of cwnd just before loss event

Can you identify different phases

Connection Timeline



Summary TCP Congestion Control

timeoutssthresh = cwnd2

cwnd = 1 MSSdupACKcount = 0

retransmit missing segment

Lcwnd gt ssthresh

congestionavoidance

cwnd = cwnd + MSS (MSScwnd)dupACKcount = 0

transmit new segment(s) as allowed

new ACK

dupACKcount++

duplicate ACK

fastrecovery

cwnd = cwnd + MSStransmit new segment(s) as allowed

duplicate ACK

ssthresh= cwnd2cwnd = ssthresh + 3


dupACKcount == 3

timeoutssthresh = cwnd2cwnd = 1 dupACKcount = 0retransmit missing segment

ssthresh= cwnd2cwnd = ssthresh + 3retransmit missing segment

dupACKcount == 3cwnd = ssthreshdupACKcount = 0

New ACK

slow start




cwnd = cwnd+MSSdupACKcount = 0transmit new segment(s) as allowed

new ACKdupACKcount++

duplicate ACK

Lcwnd = 1 MSS

ssthresh = 64 KBdupACKcount = 0

NewACK

NewACK

NewACK


TCP throughput

whatrsquos the average throughout of TCP as a function of window size and RTT ignore slow start

let W be the window size when loss occurs when window is W throughput is WRTT just after loss window drops to W2

throughput to W2RTT average throughout 75 WRTT


TCP Futures TCP over ldquolong fat pipesrdquo

example 1500 byte segments 100ms RTT want 10 Gbps throughput

requires window size W = 83333 in-flight segments

throughput in terms of loss rate

L = 210-10 Wow ndash a very small loss rate new versions of TCP for high-speed

LRTT

MSS221


fairness goal if K TCP sessions share same bottleneck link of bandwidth R each should have average rate of RK

TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair

two competing sessions additive increase gives slope of 1 as throughout increases multiplicative decrease decreases throughput proportionally

R

R

equal bandwidth share

Connection 1 throughputConnect

ion 2

th

roughput

congestion avoidance additive increaseloss decrease window by factor of 2



Fairness (more)

Fairness and UDP multimedia apps

often do not use TCP do not want rate

throttled by congestion control

instead use UDP pump audiovideo at

constant rate tolerate packet loss

Fairness and parallel TCP connections

nothing prevents app from opening parallel connections between 2 hosts

web browsers do this example link of rate R

supporting 9 connections new app asks for 1 TCP

gets rate R10 new app asks for 11 TCPs

gets R2


Chapter 3 Summary principles behind

transport layer services multiplexing

demultiplexing reliable data transfer flow control congestion control

instantiation and implementation in the Internet UDP TCP

Next leaving the

network ldquoedgerdquo (application transport layers)

into the network ldquocorerdquo

Netstat

netstat ndasha ndashn Shows open connections in various states Example

Active Connections

Proto LocalAddr ForeignAddr StateTCP 000023 00000 LISTENINGTCP 1921680100139 2072008922580 CLOSE_WAITTCP 19216801001275 12832449622 ESTABLISHEDUDP 1270011070

Quiz

What are three primary mechanisms of TCP Congestion Control

What are the two TCP loss events How many packets are transmitted in

the first 4 RTT durations after a TCP connection is established


Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH

TCP Header Header Length


Implications of Field Length (cont)

TCP Header Common Options


Three-Way Handshake



TCP seq rsquos and ACKs



Chapter 3 outline (2)


TCP Quiz -2

TCP sender events

TCP sender (simplified)



TCP Round Trip Time and Timeout

TCP Round Trip Time and Timeout (2)

Example RTT estimation

Fast Retransmit

Slide 31


TCP Flow Control



TCP Connection Management (2)

TCP Connection Management (cont) (2)



Quiz





Congestion scenario 2a ideal case


Congestion scenario 2b known loss (2)


Congestion scenario 2c duplicates (2)


Causescosts of congestion scenario 3 (2)



TCP congestion control additive increase multiplicative decre


TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)

Transport Layer 3-2

Chapter 3 outline



management



Transport Layer 3-3







overwhelm receiver







socketdoor

T C Psend buffer

T C Preceive buffer

socketdoor

segm ent



Transport Layer 3-4



32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused



ACK ACK valid



commands)



Internetchecksum

(as in UDP)

Transport Layer 3-5



32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused














is valid


TCP Header ACK flag





TCP Header PUSH











32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused












119 MB














Socket(hostnameport




Three way handshake






Three-Way Handshake




SYN SequenceNum = x




SequenceNum = x+1
















ACKs seq of next





Host A Host B



Seq=43 ACK=80

Usertypes

lsquoCrsquo

host ACKsreceipt


host ACKsreceipt of















client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait


Chapter 3 outline



management










TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)

Transport Layer 3-3







overwhelm receiver







socketdoor

T C Psend buffer

T C Preceive buffer

socketdoor

segm ent



Transport Layer 3-4



32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused



ACK ACK valid



commands)



Internetchecksum

(as in UDP)

Transport Layer 3-5



32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused














is valid


TCP Header ACK flag





TCP Header PUSH











32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused












119 MB














Socket(hostnameport




Three way handshake






Three-Way Handshake




SYN SequenceNum = x




SequenceNum = x+1
















ACKs seq of next





Host A Host B



Seq=43 ACK=80

Usertypes

lsquoCrsquo

host ACKsreceipt


host ACKsreceipt of















client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait


Chapter 3 outline



management










TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)

Transport Layer 3-4



32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused



ACK ACK valid



commands)



Internetchecksum

(as in UDP)

Transport Layer 3-5



32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused














is valid


TCP Header ACK flag





TCP Header PUSH











32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused












119 MB














Socket(hostnameport




Three way handshake






Three-Way Handshake




SYN SequenceNum = x




SequenceNum = x+1
















ACKs seq of next





Host A Host B



Seq=43 ACK=80

Usertypes

lsquoCrsquo

host ACKsreceipt


host ACKsreceipt of















client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait


Chapter 3 outline



management










TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)

Transport Layer 3-5



32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused














is valid


TCP Header ACK flag





TCP Header PUSH











32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused












119 MB














Socket(hostnameport




Three way handshake






Three-Way Handshake




SYN SequenceNum = x




SequenceNum = x+1
















ACKs seq of next





Host A Host B



Seq=43 ACK=80

Usertypes

lsquoCrsquo

host ACKsreceipt


host ACKsreceipt of















client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait


Chapter 3 outline



management










TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)







is valid


TCP Header ACK flag





TCP Header PUSH











32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused












119 MB














Socket(hostnameport




Three way handshake






Three-Way Handshake




SYN SequenceNum = x




SequenceNum = x+1
















ACKs seq of next





Host A Host B



Seq=43 ACK=80

Usertypes

lsquoCrsquo

host ACKsreceipt


host ACKsreceipt of















client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait


Chapter 3 outline



management










TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)

TCP Header ACK flag





TCP Header PUSH











32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused












119 MB














Socket(hostnameport




Three way handshake






Three-Way Handshake




SYN SequenceNum = x




SequenceNum = x+1
















ACKs seq of next





Host A Host B



Seq=43 ACK=80

Usertypes

lsquoCrsquo

host ACKsreceipt


host ACKsreceipt of















client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait


Chapter 3 outline



management










TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)

TCP Header PUSH











32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused












119 MB














Socket(hostnameport




Three way handshake






Three-Way Handshake




SYN SequenceNum = x




SequenceNum = x+1
















ACKs seq of next





Host A Host B



Seq=43 ACK=80

Usertypes

lsquoCrsquo

host ACKsreceipt


host ACKsreceipt of















client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait


Chapter 3 outline



management










TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)








32 bits

applicationdata

(variable length)

sequence number



FSRPAUheadlen

notused












119 MB














Socket(hostnameport




Three way handshake






Three-Way Handshake




SYN SequenceNum = x




SequenceNum = x+1
















ACKs seq of next





Host A Host B



Seq=43 ACK=80

Usertypes

lsquoCrsquo

host ACKsreceipt


host ACKsreceipt of















client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait


Chapter 3 outline



management










TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)











119 MB














Socket(hostnameport




Three way handshake






Three-Way Handshake




SYN SequenceNum = x




SequenceNum = x+1
















ACKs seq of next





Host A Host B



Seq=43 ACK=80

Usertypes

lsquoCrsquo

host ACKsreceipt


host ACKsreceipt of















client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait


Chapter 3 outline



management










TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)













Socket(hostnameport




Three way handshake






Three-Way Handshake




SYN SequenceNum = x




SequenceNum = x+1
















ACKs seq of next





Host A Host B



Seq=43 ACK=80

Usertypes

lsquoCrsquo

host ACKsreceipt


host ACKsreceipt of















client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait


Chapter 3 outline



management










TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)

Three-Way Handshake




SYN SequenceNum = x




SequenceNum = x+1
















ACKs seq of next





Host A Host B



Seq=43 ACK=80

Usertypes

lsquoCrsquo

host ACKsreceipt


host ACKsreceipt of















client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait


Chapter 3 outline



management










TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)
















ACKs seq of next





Host A Host B



Seq=43 ACK=80

Usertypes

lsquoCrsquo

host ACKsreceipt


host ACKsreceipt of















client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait


Chapter 3 outline



management










TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)













client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait


Chapter 3 outline



management










TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


Chapter 3 outline



management










TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)








TCP Quiz -2





















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)



















end of loop forever




Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


Host A


ACK=100

time

premature timeout

Host B

Seq=92 8 bytes data

ACK=120

Seq=92 8 bytes data

Seq=

92

tim

eout

ACK=120

Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout

lost ACK scenario

Host B

X

Seq=92 8 bytes data

ACK=100

time

Seq=

92

tim

eout

SendBase= 100

SendBase= 120

SendBase= 120

SendBase= 100



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)



Host A

Seq=92 8 bytes data

ACK=100

loss

tim

eout


Host B

X


ACK=120

time

SendBase= 120


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


















100

150

200

250

300

350

1 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106

time (seconnds)

RTT

(mill

isec

onds

)



Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


Fast Retransmit



ACKs




Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


Host A

tim

eout

Host B

time

X



Seq=92 8 bytes data

ACK=100


ACK=100

ACK=100

ACK=100


ACK=180


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


Chapter 3 outline



management




TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


TCP Flow Control






much too fast

flow control





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)





LastByteRead]





Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


Chapter 3 outline



management









Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)







Socket(hostnameport




Three way handshake











client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)







client

FIN

server

ACK

ACK

FIN

close

close

closed

tim

ed w

ait






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)






client

FIN

server

ACK

ACK

FIN

closing

closing

closed

tim

ed w

ait

closed



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)



TCP clientlifecycle

TCP serverlifecycle


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


control



Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


Chapter 3 outline



management








a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)






a top-10 problem





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)





no retransmission





Host B

lout

lin original data

lout






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)






Host A

lin original data

Host B


retransmitted data

lsquo





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)





Host A

lin original data

Host B


retransmitted data

copy

R2

R2lin

l out

free buffer space


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


Host A

lin original data

Host B


retransmitted data

copy

no buffer space






Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)



Host A

lin original data

Host B


retransmitted data

free buffer space



R2

R2lin

l out





Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)




Host A

lin

Host B

loutlincopy

free buffer space


timeout

R4

R4lin

l out







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)







R4

R4lin

l out



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)



lin


lin



Host B

lout






Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)





Host A

Host B

lo

u

t













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)













Chapter 3 outline



management







loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)





loss

8 Kbytes

16 Kbytes

24 Kbytes

time

congestionwindow

time

cwnd

con

gest

ion

win

dow

siz

e


for bandwidth










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)










timeout events

rate = cwnd

RTT Bytessec


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


TCP Slow Start



Host A

one segment

RTT

Host B

time

two segments

four segments










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)










Philosophy


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


Refinement






Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)

Connection Timeline







Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)






Lcwnd gt ssthresh

congestionavoidance



new ACK

dupACKcount++

duplicate ACK

fastrecovery


duplicate ACK



dupACKcount == 3




New ACK

slow start






duplicate ACK

Lcwnd = 1 MSS


NewACK

NewACK

NewACK


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


TCP throughput










LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)







LRTT

MSS221



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)



TCP connection 1

bottleneckrouter

capacity R

TCP connection 2

TCP Fairness


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


TCP is fair


R

R



ion 2

th

roughput




Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)


Fairness (more)











gets R2






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)






Next leaving the



Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)

Netstat


Active Connections


Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)

Quiz





Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)

Quiz (cont)


Slide 1

Chapter 3 outline





TCP Header ACK flag

TCP Header PUSH






Three-Way Handshake








TCP Quiz -2

TCP sender events







Fast Retransmit

Slide 31


TCP Flow Control







Quiz
















TCP Slow Start


Refinement

Connection Timeline


TCP throughput


TCP Fairness

TCP is fair

Fairness (more)

Chapter 3 Summary

Netstat

Quiz (2)

Quiz (cont)

CSCI 3335: C OMPUTER N ETWORKS C HAPTER 3 T RANSPORT L AYER Vamsi Paruchuri University of Central...

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Transcript of CSCI 3335: C OMPUTER N ETWORKS C HAPTER 3 T RANSPORT L AYER Vamsi Paruchuri University of Central...