Wnp Mpr Fundaments

WNP-MPR-Fundaments 1

Wireless Networks and Protocols

MAP-Tele

Manuel P. Ricardo

Faculdade de Engenharia da Universidade do Porto


Professors

Adriano Moreira (WNP Coordinator)

Universidade do Minho

Manuel P. Ricardo ([email protected])

Faculdade de Engenharia, Universidade do Porto Faculdade de Engenharia, Universidade do Porto

[email protected]

http://www.fe.up.pt/~mricardo

Tel. 22 209 4200

Rui L. Aguiar

Universidade de Aveiro


Goals of the Course

The WNP course has two main objectives

provide competences to understand current wireless networks and their functions

provide competences required to create future wireless networks and their functions


Syllabus

Introduction to Wireless Networks and Protocols

What are Wireless networks

History of wireless networks

Standards and market issues

Evolution and trends on wireless networking Evolution and trends on wireless networking

Fundamentals of wireless communications

Transmission

Wireless data links and medium access control

Networking

Mobility concepts and management

Research issues


Syllabus

Telecommunications systems

GSM and GPRS

UMTS

TETRA

Broadcast and satellite: DVB, DMB

IEEE wireless data networks

5

IEEE wireless data networks

WLAN: 802.11

WMAN: 802.16

WPAN: 802.15

Convergence and interoperability of wireless systems

4G wireless networks

3GPP and Mobile IPv6 approaches

Integration of ad-hoc networks

Research issues


Syllabus

Quality of service

Characterization and models

Case studies: 3GPP-QoS, IEEE-QoS, IP-QoS

Research issues

6

Support for services and applications

Web services components: XML and SOAP, UDDI and WSDL

Services and applications platforms

Research issues


Bibliography

Handouts

Recommended papers

Chapters from multiple books Wireless and Mobile Network Architectures, Yi-Bing Lin, Imrich Chlamtac Wiley, 2001

Wireless IP and Building the Mobile Internet, Sudhir Dixit, Ramjee Prasad, Artech House, 2002.

The 3G IP Multimedia Subsystem, Merging the Internet and the Cellular Worlds, Gonzalo Camarillo and Miguel a. Garcia-Martin,Wiley, Second Edition, 2005

Ad-hoc Wireless Networks, Architectures and Protocols, C. Silva Murthy, B. Manoj, Prentice Hall, 2004

7

Ad-hoc Wireless Networks, Architectures and Protocols, C. Silva Murthy, B. Manoj, Prentice Hall, 2004

Advanced Wireless Networks - 4G Technologies, S. Glisic, Wiley, 2006.

Mobile Communications, Jochen Schiller, Second Edition, Addison-Wesley, 2003

Wireless Communications - Principles and Practice, Theodore S. Rappaport, Second Edition, Prentice Hall, 2002

Mobile IP Technology and Applications, Stefan Raab and Madhavi W. Chandra, Cisco Press, 2005

GSM cellular radio telephony, Joachim Tisal, John Wiley & Sons, 1997

Wireless Communications and Networks, William Stallings, Prentice Hall, 2002

WCDMA for UMTS : radio acess for third generation mobile communications, Harri Holma, John Wiley & Sons, 2000

UMTS networks : architecture, mobility and services, Heikki Kaaranen, et al, John Wiley & Sons, 2001


Evaluation

Final Exam - 40%

Review of 3 papers - 30%

8

Small project - 30%


Topics Scheduled for Today


Fundamentals of wireless communications

Transmission

Next week

Wireless data links and medium access control

Networking

Mobility concepts and management

Research issues

Today


Mobile vs Fixed networks

Mobile communications systems characterised by

wireless links

mobility of terminals

T

switch

AP

TAP

1

2

1

2

Terminal

Mobility

Computer Switch

Computer AP

Wireless link

Wired link


Wireless Link

Susceptible to noise Susceptible to noise

large % of bits received in error

Broadcast nature

Demands security mechanisms

Adequate for broadcast services


To Think About

How to obtain a low Bit Error Ratio (BER) in a wireless link?


Today

Transport

Application

Physical

Network

Data link

M

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Wireless Data Link

and and

Medium Access Control



A. The Basic Framework


Fundamentals of wireless communications (brief overview)

Transmission

Wireless data links and medium access control Wireless data links and medium access control

Networking

Why wireless? Mobility concepts and management

Research issues

B. The Existing Practices and Concepts


How to transmit signals in both directions simultaneously?

How to enable multiple users to communicate simultaneously?


Radio Link Model

Wireless physical layer

provides virtual link of unreliable bits

service described in terms of

Gross bit rate R, r (bit/s)

Bit error ratio BER, e

Tx Rcv

In absence of link adaptation

R constant

BER absorbs channel variability

Using link adaptation techniques

BER usually kept bounded

R changes

0 1 2 M-1

0

1

1

2

2

3

2

1r0 e0 r1 e1 r2 e2 rM-1 eM-1

Adaptive Transmitter

Physical layer


Duplex Transmission

Duplex transference of data in both directionsUplink and Downlink channels required

Two methods for implementing duplexing Two methods for implementing duplexing

Frequency-Division Duplexing (FDD)

wireless link split into frequency bands

bands assigned to uplink or downlink directions

peers communicate in both directions using different bands

Time-Division Duplexing (TDD)

timeslots assigned to the transmitter of each direction

peers use the same frequency band but at different times


Duplex Transmission


To Think About

How to place several sender-receiver pairs communicating in the

same physical space?same physical space?


Multi-Access Schemes

Multi-access schemes

Identify radio resources

Assign resources to multiple users/terminals

Multi-access schemes Multi-access schemes

Frequency-Division Multiple Access (FDMA)

resources divided in portions of spectrum (channels)

Time-Division Multiple Access (TDMA)

resources divided in time slots

Code-Division Multiple Access (CDMA)

resources divided in codes

Space-Division Multiple Access (SDMA)

resources divided in areas


FDMA

Signal space divided along the frequency axis

into non-overlapping channels

Each user assigned a different frequency channel

The channels often have guard bands

Transmission is continuous over time

channel k

channel 2

time

c

o

d

e

channel 1


TDMA

Signal space divided along the time axis

into non-overlapping channels

Each user assigned a different cyclically-repeating timeslot

Transmission not continuous for any user

Major problem

synchronization among the users in the uplink channels

users transmit over channels having different delays

uplink transmitters must synchronize

timec

o

d

e


CDMA

Each user assigned a code to spread his information signal

Multi-user spread spectrum (Direct Sequence, Frequency Hopping)

The resulting spread signal occupy the same bandwidth

transmitted at the same time

c

o

d

e

Different bitrates to users

control length of codes

Power control required in uplink

to compensate near-far effect

If not, interference from close user swamps signal from far user

time

channel 1

channel 2

channel k


SDMA

SDMA uses direction (angle) to assign channels to users

Implemented using sectorized antenna arrays

the 360 angular range divided in N sectors

TDMA or FDMA then required to channelize users

Cellular division of the space

is also SDMA

BS

MT-1

MT-2

MT-k


Combined Multi-access Techniques

Current technologies combinations of multi-access techniques

GSM: FDMA and then TDMA to assign slots to users

The cell concept combined multi-access technique

SDMA + FDMA

Cellular planning Cellular planning

f1

f3

f3

f2

f2

f1

f3

f1

f3

f3

f2

f2

f1

f3

f1

f3

f3

f2

a) Group of 3 cells

f4

f2

f6

f3

f5

f2

f1

f6

f3

f5

f7

f2

f3

f4

f5

f7

f2

f1

b) Group of 7 cells c) Group of 3 cells, each having 3 sectors

f2

f3f1

f2

f3f1

f2

f3f1

f5

f6f4

f5

f6f4

f8

f9f7

f8

f9f7

f8

f9f7


Wireless Medium Access Control Issues

Medium Access Control (MAC)

Assign radio resources to terminals along the time

3 type of resource allocation methods

dedicated assignment dedicated assignment

resources assigned in a predetermined, fixed, mode

random access

terminals contend for the channel

demand-based

terminals ask for reservations

using dedicated/random access channels


Hidden, Exposed and Capture Nodes

Signal strength decays with the path length

Carrier sensing depends on the position of the receiver

MAC protocols using carrier sensing 3 type of nodes

hidden nodes

C is hidden to A

exposed nodes

C is exposed to B

capture nodes

D captures A

A CB

D


Hidden, Exposed and Capture Nodes

Hidden node C is hidden to A A transmits to B; C cannot hear A

If C hears the channel it thinks channel is idle; C starts transmitting interferes with data reception at B

In the range of receiver; out of the range of the sender

Exposed node C is exposed to B B transmits to A; C hears B; C does not transmit; but C transmission would not interfere with A reception

In the range of the sender; out of the range of the receiver

Capture D captures A receiver can receive from two senders receiver can receive from two senders

A and D transmit simultaneously to B; but signal from D much higher than that from A

A CB

D


Alhoa, S-Alhoa, CSMA

Alhoa Efficiency of 18 %if station has a packet to transmit

u transmits the packet

u waits confirmation from receiver (ACK)

u if confirmation does not arrive in round trip time, the station

computes random backofftime retransmits packet

Slotted Alhoa Efficiency of 37 %stations transmit just at the beginning of each time slot

Carrier Sense Multiple Access (CSMA) Efficiency of 54 % station listens the carrier before it sends the packet

If medium busy station defers its transmission

ACK required for Alhoa, S-Alhoa and CSMA


CSMA/CD Not Used in Wireless

CDMA/Collision Detection Efficiency < 80% station monitors de medium (carrier sense)

u medium free transmits the packet

u medium busy waits until medium is free transmits packet

u if, during a round trip time, detects a collision

station aborts transmission and stresses collision station aborts transmission and stresses collision

(no ACK packet)

Problems of CDMA/CD in wireless networksCarrier sensing

carrier sensing difficult for hidden terminal

Collision detection

near-end interference makes simultaneous transmission and reception difficult


To think about?

How to minimize collision in a wireless medium?


CSMA with Collision Avoidance (CSMA/CA)

S2

DIFS

S1DATA

DIFS S2-bo

DATA

S3

DIFS S3-bo

S3-bo-e S3-bo-r

DIFSS3-bo-r

DATA

- Packet arrivalDATA

- Transmission of DATA DIFS - Time interval DIFS S2-bo - Backoff time, station 2

- Elapsed backoff time, station 3S3-bo-e S3-bo-r

- Remaining backoff time, station 3


CSMA with Collision Avoidance (CSMA/CA)

Station with a packet to transmit monitors the channel activity until an idle period equal to a Distributed Inter-Frame Space (DIFS) has been observed

If the medium is sensed busy a random backoff interval is selected. The backoff time counter is decremented as long as the selected. The backoff time counter is decremented as long as the channel is sensed idle, stopped when a transmission is detected on the channel, and reactivated when the channel is sensed idle again for more than a DIFS. The station transmits when the backoff time reaches 0

To avoid channel capture, a station must wait a random backoff time between two consecutive packet transmissions, even if the medium is sensed idle in the DIFS time


CSMA/CA ACK Required

DIFS

S1

SIFS

DATA

ACK

SIFS

ACK

AP

S2

ACK

DIFS S2-Backoff

DATA

ACK


- Transmission of DATA DIFS - Time interval DIFS


CSMA/CA ACK Required

CSMA/CA does not rely on the capability of the stations to detect a collision by hearing their own transmission

A positive acknowledgement is transmitted by the destination station to signal the successful packet transmission

In order to allow an immediate response, the acknowledgement is transmitted In order to allow an immediate response, the acknowledgement is transmitted following the received packet, after a Short Inter-Frame Space (SIFS)

If the transmitting station does not receive the acknowledge within a specified ACK timeout, or it detects the transmission of a different packet on the channel, it reschedules the packet transmission according to the previous backoff rules.

Efficiency of CSMA/CA depends strongly of the number of competing stations. An efficiency of 60% is commonly found


To Think About

How to enable hidden terminals to sense the carrier?

Hidden node C is hidden to A

A CB

D


RTS-CTS Mechanism

DIFS

S1

SIFS

DATARTS

SIFS

SIFS

AP

S2

DIFS S2-bo

DATA


- Transmission of DATA DIFS - Time interval DIFS

CTS ACK


RTS-CTS Mechanism

For some scenarios where long packets are used or the probability of hidden terminals is not irrelevant, the efficiency of CSMA/CA can be further improved with a Request To Send (RTS) - Clear to Send (CTS) mechanism

The basic concept is that a sender station sends a short RTS message to the receiver station. When the receiver gets a RTS from the sender, it polls the sender by sending a short CTS message. The sender then sends its packet to the receiver. After correctly receiving the packet, the receiver sends a positive acknowledgement (ACK) to the senderreceiving the packet, the receiver sends a positive acknowledgement (ACK) to the sender

This mechanism is particularly useful to transmit large packets. The listening of the RTS or the CTS messages enable the stations in range respectively of the sender or receiver that a big packet is about to be transmitted. Usually both the RTS and the CTS contain information about the number of slots required to transmit the 4 packets. Using this information the other stations refrain themselves to transmit packets, thus avoiding collisions and increasing the system efficiency.

SIFS are used before the transmission of CTS, Data, and ACK

In optimum conditions the RTS-CTS mechanism may add an efficiency gain of about 15%


Guaranteed Access Control

Polling

AP manages stations access to the medium

Channel tested first using a control handshake


Fundamental NetworkingFundamental Networking






Transmission


Networking


Research issues



What networking concepts shall I have present from previous courses?

What are the differences between L2 and L3 networks?

What is a tunnel? What is a virtual network? Why are they relevant? What is a tunnel? What is a virtual network? Why are they relevant?

What are the differences between IPv4 and IPv6?


Switching: Circuits, Virtual Circuits, Datagram


Circuit Switching

Technologies: ISDN: Basic Rate Access, E1 time slots for 64 kbit/s channels

Path defined during call establishment, based on the called number

Switching

Exchange of time slots

In time and in space

Inputs required to be synchronised


Virtual Circuit Switching

Technologies: ATM, MPLS

Path

defined during the virtual circuit establishment

Defined as a set of nodes, ports, labels

Switching

Cells, packets

Exchange of labels Exchange of labels

Tabela de translao de

portas / canais virtuais

1

M

a

t

1

N

2

t

Entrada

M

abc

yzc

1N2

21N

kh

m

nng

Sada

1

Porta CV Porta CV

comutao

espacial

comutao

de etiqueta

b c c

y c z y

controlo de

comutao

g h

n

k kn

m

g

cabealho

dados

a, b, c, ... indicador de canal virtual

b a


Packet Switching

Technologies: Ethernet, IP

Path defined by packet destination address


To Think About

Suppose terminal a moves from port 2 to port 1

What needs to be done so that terminal a can continue receiving packets?


L2 Networking Frame Formats

Ethernet

7x 10101010 10101011

Protocolo=IP

PPPBit stuffing 5 1s seguidos emissor introduz 0


L2 Networking - Bridge

Interconnects

2 LAN technologies

2 segments of the same technology

Bridge builds forwarding tables automatically Address learning

Source Address of received frame is associated to a bridge input port station reachable trough that port station reachable trough that port

Frame forwarding

When a frame is received, its Destination Address is analysed If address is associated to a port frame forwarded to that port

If not frame transmitted through all the ports but the input port


L2 Networking - Single Tree Required

Ethernet frame

No hop-count

Could loop forever in a L2 mis-configured network

Same for broadcast packet

Layer 2 network

Tree topology

Single path between every pair of stations

Spanning Tree (ST) Protocol

Running in bridges

Helps building the spanning tree

Blocks ports


Ethernet Switch

The computer attached to a port gets the illusion to have

its own LAN segment

its LAN segment bridged to all the other segments


Virtual LANs

One bridge/switch simulates multiple LANs / broadcast domains

One LAN may be extended to other bridges

w xw

y

VLAN 100

VLAN 200

B1

x

z

VLAN 100

VLAN 200

B2

[da=broadcast; sa=x; data]

[da=broadcast; sa=x; vlanid=100; data]

[da=broadcast; sa=x; data]


L3 Networking Packet Formats

Version HLen TOS Length

Ident Flags Offset

TTL Protocol Checksum

SourceAddr

0 4 8 16 19 31

Version Traffic Class Flow Label

Payload Lengtht Next Header Hop Limit

SourceAddr (4 words)

0 4 8 16 24 31

SourceAddr

DestinationAddr

Options (variable)Pad

(variable)

Data

DestinationAddr (4 words)

Options (variable number)

Data

IPv4 IPv6


L3 Networking Router

3 generation router


L3 Networking Multiple Trees

Every router

finds the shortest path to the other routers and their attached networks

Calculates its Shortest Path Tree (SPT)

Routing protocol

Runs in routers Runs in routers

Helps routers build their SPT

RIP, OSPF, BGP

Destination Cost NextHop

A 1 A

C 1 C

D 2 C

E 2 A

F 2 A

G 3 A

Bs routing view

D

G

A

F

E

B

C


TCP

Point to connection between a client and a server; port-to-port

Reliable, flow control Sender

Data (SequenceNum)

Acknowledgment +AdvertisedWindow

Receiver

Congestion control

AdvertisedWindow


Multimedia Traffic - Taxonomy

Applications

Elastic Real time (variation of the packet end-to-end delay)

Intolerant Tolerant

Nonadaptive Adaptive

Delay adaptiveRate adaptive

(packet loss)

(application reaction to packet loss)

(type of reaction)


RTP+RTCP/UDP

Multimedia traffic

Application-Level Framing

Data Packets (RTP)

sequence number

timestamp (app defines tick) timestamp (app defines tick)

transported as UDP packets

Control Packets (RTCP)

sent periodically

report loss rate (fraction of packets received since last report)

report measured jitter


Traditional TCP/IP Communications Stack

IETF IP address

based

switching

T1

IP

TCP

APP

T1 | T2 T2 | T3

IP

T3 | T4

IP

T5

IP

TCP

APP

host bridge router router host

T4 | T5

bridge

IEEE MAC address

based

switching


Tunnel IP-in-IP

T1

IP

TCP

APP

T1 | T2 T2 | T3

IP

T3 | T4 T5

IP

TCP

APP

H1 bridge R1 R2 Server

T4 | T5

bridge

IP IP

IP

outer IP header inner IP header data

DA= 2nd IP address of R2SA= 2nd IP address of H1

TTLIP identification

IP-in-IP IP checksumflags fragment offset

lengthTOSver. IHL

DA= ServerSA=H1

TTLIP identification

lay. 4 prot. IP checksumflags fragment offset

lengthTOSver. IHL

TCP/UDP/ ... payload


Tunnel PPP over IP (E.g PPTP)

T1

IP

TCP

APP

T1 | T2 T2 | T3

IP

T3 | T4 T5

IP

TCP

APP

H1 bridge R1 R2 Server

T4 | T5

bridge

IP IP

IP

PPP

GREGRE

PPP

GRE virtual point-to-point link

encapsulates a variety of

network layer protocols

routers at remote points

over an IP network

PPP adequate for Authentication

Transporting IP packets


PPP over Ethernet

- In an ADSL router/modem the protocols of Host PC and ADSL modem are combined in a single network element


IPv6IPv6


The Need of a New IP

IPv4 Small addressing space (32 bits)

Non-continuous usage

Some solutions used to overcome these problems

private networks (NAT), classless networks (CDIR)

IETF developed new IP version: IPv6 Same principles of IPv4

Many improvements

Header re-defined

IPv6 may be relevant for mobile communications


IPv6 Improvements

128 bit addresses (16 octets, 8 shorts ). No classes

Better QoS support (flow label)

Native security functions (peer authentication, data encryption)

Autoconfiguration (Plug-n-play)

Routing

Multicast


8 x 16 bit, hexadecimal. Separated by :

47CD : 1234 : 3200 : 0000 : 0000 : 4325 : B792 : 0428

Compressed format: FF01:0:0:0:0:0:0:43 FF01::43

Address Representation

Compatibility with IPv4: 0:0:0:0:0:0:13.1.68.3 or ::13.1.68.3

Loopback address: ::1

Network prefix described by / , same as IPv4

FEDC:BA98:7600::/40 network prefix = 40 bits


Reserved Addresses

Allocation Prefix Fraction of(binary) Address Space

----------------------------------- -------- -------------

Unassigned 0000 0000 1/256Unassigned 0000 0001 1/256Reserved for NSAP Allocation 0000 001 1/128Unassigned 0000 01 1/64Unassigned 0000 1 1/32Unassigned 0001 1/16Unassigned 0001 1/16Global Unicast 001 1/8 Unassigned 010 1/8Unassigned 011 1/8Unassigned 100 1/8Unassigned 101 1/8Unassigned 110 1/8Unassigned 1110 1/16Unassigned 1111 0 1/32Unassigned 1111 10 1/64Unassigned 1111 110 1/128Unassigned 1111 1110 0 1/512Link-Local Unicast Addresses 1111 1110 10 1/1024Site-Local Unicast Addresses 1111 1110 11 1/1024Multicast Addresses 1111 1111 1/256


Adresses

Link-Local, Site-Local, Global Unicast, Anycast

Link-Local

Used for communication between hosts in the same LAN /link

Address built from MAC address

Routers do not foward packets having Link-Local destination addresses

Site-Local

Not used anymore Not used anymore

Global Unicast

Global addresses

Address: network prefix + computer identifier

Structured prefixes

Network aggregation; less entries in the router forwarding tables

Anycast

Group address; packet is received by any (only one) member of the group

Multicast

Group address; packet received by all the members of the group


Address Formats

| n bits | m bits | 128-n-m bits | Global Unicast Address+------------------------+-----------+----------------------------+ (2000::/3)|001 global rout prefix | subnet ID | interface ID |+------------------------+-----------+----------------------------+

| 10 || bits | 54 bits | 64 bits | Link-Local Unicast address+----------+-------------------------+----------------------------+ (fe80::/10)|1111111010| 0 | interface ID | +----------+-------------------------+----------------------------+

| 10 || bits | 54 bits | 64 bits | Site-Local Unicast address+----------+-------------------------+----------------------------+ (fec0::/10) |1111111011| subnet ID | interface ID |+----------+-------------------------+----------------------------+

| n bits | 128-n bits | Anycast address+------------------------------------------------+----------------+

| subnet prefix | 00000000000000 |+------------------------------------------------+----------------+

| 8 | 4 | 4 | 112 bits |+------ -+----+----+---------------------------------------------+

|11111111|flgs|scop| group ID |+--------+----+----+---------------------------------------------+

Multicast addressScope link, site, global, ...

(ff::/8)


Headers IPv4 and IPv6

Version HLen TOS Length

Ident Flags Offset

TTL Protocol Checksum

SourceAddr

0 4 8 16 19 31




0 4 8 16 24 31

SourceAddr

DestinationAddr

Options (variable)Pad

(variable)

Data



Data

IPv4 IPv6


IPv6 Header

Flow label identifies packet flow

QoS, resource reservation

Packets receive same service

Payload length




0 4 8 16 24 31

Payload length

Header not included

Hop limit = TTL (v4)

Next header

Identifies next header/extension

Options included as extension headers



Data


Extension Headers

IPv6 HeaderNext Header = TCP

TCP header + data

Routing HeaderNext Header = TCP

TCP header + dataIPv6 HeaderNext Header = Routing

IPv6 HeaderNext Header = Routing

Routing HeaderNext Header = Fragment

Fragment HeaderNext Header = TCP

Fragment of

TCP header + data

IPv6 Hop-by-hop TCPDestination Routing Fragment Authenticate. ESP


Extension Headers

Hop-by-hop

additional information, inspected by every node traversed by the packet

Other header are inspected only at the destination or at pre-defined nodes

Destination: Information for the destination node Destination: Information for the destination node

Routing: List of nodes to be visited by the packet

Fragmentation: Made by the source; it shall find MPU

Authentication: Authentication (signature) of packet header

ESP: Data encryption


Routing Header -

Pacote sent from S to D, through I1, I2, I3As the packet travels from S to I1:

Source Address = S Hdr Ext Len = 6Destination Address = I1 Segments Left = 3

Address[1] = I2Address[2] = I3Address[3] = D

As the packet travels from I1 to I2:

Source Address = S Hdr Ext Len = 6Destination Address = I2 Segments Left = 2Destination Address = I2 Segments Left = 2


As the packet travels from I2 to I3:

Source Address = S Hdr Ext Len = 6Destination Address = I3 Segments Left = 1


As the packet travels from I3 to D:

Source Address = S Hdr Ext Len = 6Destination Address = D Segments Left = 0

Address[1] = I1Address[2] = I2Address[3] = I3

List of visited nodes


Configuration examples in Linux

tux13:~# /sbin/ifconfig eth0 inet6 add 2000:0:0:1::1/64tux13:~# ifconfig eth0eth0 Link encap:Ethernet HWaddr 00:C0:DF:08:D5:99

inet addr:172.16.1.13 Bcast:172.16.1.255 Mask:255.255.255.0inet6 addr: 2000:0:0:1::1/64 Scope:Globalinet6 addr: fe80::2c0:dfff:fe08:d599/10 Scope:LinkUP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1RX packets:81403 errors:0 dropped:0 overruns:0 frame:0TX packets:2429 errors:0 dropped:0 overruns:0 carrier:0TX packets:2429 errors:0 dropped:0 overruns:0 carrier:0collisions:0 txqueuelen:100RX bytes:4981344 (4.7 MiB) TX bytes:260692 (254.5 KiB)Interrupt:5

tux13:~# /sbin/route -A inet6 add 2000::/3 gw 2000:0:0:1::aatux13:~# route -A inet6Kernel IPv6 routing tableDestination NextHop Flags Metric Ref Use Iface::1/128 :: U 0 0 0 lo2000:0:0:1::1/128 :: U 0 0 0 lo2000:0:0:1::/64 :: UA 256 0 0 eth02000::/3 2000:0:0:1::aa UG 1 0 0 eth0 fe80::2c0:dfff:fe08:d599/128 :: U 0 0 0 lofe80::/10 :: UA 256 0 0 eth0ff00::/8 :: UA 256 0 0 eth0::/0 :: UDA 256 0 0 eth0


Identifier IEEE EUI-64

Method to create a IEEE EUI-64 identifier from an IEEE 48bit MAC identifier. This is to insert two octets, with hexadecimal values of 0xFF and 0xFE, in the middle of the 48 bit MAC (between the company_id and vendor supplied id). For example, the 48 bit IEEE MAC with global scope:

|0 1|1 3|3 4||0 5|6 1|2 7|+----------------+----------------+----------------+

|cccccc0gcccccccc|ccccccccmmmmmmmm|mmmmmmmmmmmmmmmm||cccccc0gcccccccc|ccccccccmmmmmmmm|mmmmmmmmmmmmmmmm|+----------------+----------------+----------------+ 00:C0:DF:08:D5:99

where "c" are the bits of the assigned company_id, "0" is the value of the universal/local bit to indicate global scope, "g" is individual/group bit, and "m" are the bits of the manufacturer-selected extension identifier. The interface identifier would be of the form:

|0 1|1 3|3 4|4 6||0 5|6 1|2 7|8 3|+----------------+----------------+----------------+----------------+

|cccccc1gcccccccc|cccccccc11111111|11111110mmmmmmmm|mmmmmmmmmmmmmmmm|+----------------+----------------+----------------+----------------+

fe80::2c0:dfff:fe08:d599


Protocolo Neighbor Discovery (ND)

IPv6 node uses ND for

Find other nodes in the same link /LAN

Find a node MAC address

ND substitutes ARP

Find router(s) in its network

Mantaining information about neighbour nodes

ND similar to the IPv4 functions

ARP IPv4

ICMP Router Discovery

ICMP Redirect


ND Messages

ICMP messages (over IP); using Link Local addresses

Neighbor Solicitation

Sent by a host to obtain MAC address of a neighbour / to verify its presence

Neighbor Advertisement: Answer to the request Neighbor Advertisement: Answer to the request

Router Advertisement

Information about the network prefix; periodic or under request

Sent by router to IP address Link Local multicast

Router Solicitation: host solicits from router a Router Advertisment message

Redirect: Used by a router to inform na host about the best route to a destination


IPv6 Address Configuration


Packet Transmission


Mobility ManagementMobility Management






Transmission


Networking


Research issues



What are the key management concepts?

What functionality is associated to Mobility Management?


Handoff

Transference of a call, or session, to a new cell / service-area

Caused by radio link degradation ( terminal movement)

or to re-distribute traffic

T

switch

AP

TAP

1

2

1

2

Terminal

Mobility


Other Terms Used

(Terminal) Mobility types

Macro-mobility: between organizations

Micro-mobility: in the same organization

Handover types Handover types

Vertical handover: between different technologies

Horizontal handover: same technology, same organization


Macro Mobilility (e.g. Mobile IP)

Internet

Home

Corresponding

host

Same route

Organization 1 Organization 2

Mobile

node

Mobile

node


Micro-Mobility (e.g. Mobile IP)

Internet

Home

Corresponding

host

Same route

Organization 1 Organization 2

Mobile

node

Mobile

node


Mobility Management

Mobility management

Enables network to be aware of terminal location

Maintains the route/connection to the terminal when it moves

Mobility management 2 functions Location management

Handoff management


Location Management

Location registration/update Location registration/update

Terminal informs network about its current access point; regularly

Network updates terminal location

New Call/Session/Data delivery

When a new Call/Session/Data arrives to terminals home network

network requested to find the terminal location,

by querying location databases (or by paging the terminal)

location

database


Handoff Management

Maintains terminal connection/routes when terminal moves

Initiation: need for handoff identified

New connection/route generation

Resources found for the handoff connection In Network-Controlled Handoff (NCHO) the network finds the resources

In Mobile-Controlled Handoff (MCHO) terminal finds resources, network approves

Routing operations performed

Data-flow control: delivery of data from old to new paths, maintaining QoS


To Think About

1. How can I manage mobility at IP layer?


Mobility Management

Handled at multiple layers

Data Link: 3GPP, IEEE networks

Network: Mobile IP, HIP

Transport: Mobile TCP Network

Transport

Application

Q

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Application: SIP

Security and QoS

Affect Mobility Management

How to avoid new authentication at every new AP?

How to guarantee that radio resources are available at the new AP?

Physical

Data link

M

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To Think About

How does Skype manage computer mobility?


Research IssuesResearch Issues






Transmission


Networking


Research issues



Classes of Research Topics

Basic connectivity

Network

Applications

Q

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Management planes

Mobility

Security

Multicast

Quality of Service

Network

Wireless Link

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Research Topics Basic Connectivity

Wireless link

Cognitive radio

Intelligent modulation/code

Multi-radio resource management

Network

Wireless Link

Applications

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Multi-radio resource management

Optimal radio usage based on neighbours information

Software defined radio

Multi-hop mac protocols

MAC for multi-channel protocols

Combination of access techniques (increase used of SDMA)


Research Topics Basic Connectivity

Networking

Auto-configuration

Multi-homing

Mesh networks

Congestion avoidance

Network

Wireless Link

Applications

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Congestion avoidance

Bio-inspired routing paradigms

Un-planned wireless networks

Networks growing organically

Very large networks

Adequate support of demanding applications: peer-to-peer and m n

Networks driven by applications (sensor like networks)

Networks more aware of radio conditions (cognitive like networks)

Wireless Link

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Research Topics Management Planes

Moving networks

Multi-layer mobility management

Fast authentication techniques

Multilayer security techniques

Network

Wireless Link

Applications

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Multi-layer multicast management

M N communications, P2P over wireless networks

Mobility and security

Mobility and QoS

Secure multicast

Multicast with QoS

Wireless Link

M

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Papers to Review

Ajay Chandra, V. Gummalla, and John O. Limb, Wireless

Medium Access Control Protocols, IEEE Communications

Surveys , Second Quarter 2000

Fotis Foukalas, Vangelis Gazis, and Nancy Alonistioti, Cross-

Layer Design Proposals for Wireless Mobile Networks: a Survey Layer Design Proposals for Wireless Mobile Networks: a Survey

and Taxonomy, IEEE Communications Surveys & Tutorials, 1st

Quarter 2008

Provide a 2-page summary

of one of the above papers

in 2 weeks,

by email to [email protected]

Wnp Mpr Fundaments

Documents

Transcript of Wnp Mpr Fundaments