ATM in TCP/IP environment: Adaptations and Effectiveness IP-over-ATM (EXPERT).ppt Folie 2/28 Content...

ATM in TCP/IP ATM in TCP/IP environmentenvironment: : AdaptationsAdaptationsand and EffectivenessEffectivenessDipl.-Ing. Kai-Oliver Detken, BIBAATM Traffic Symposium, Mykonos, Greece, September the 17th, 1997

Bremen Institute of Industrial Technology and Applied Work Science

17.09.97 IP-over-ATM (EXPERT).ppt Folie 2/28

ContentContent• Introduction of the European ACTS project EIES

(European Information Exchange Service)• IP-over-ATM difficulty• IP-over-ATM possibilities: Classical IP, LAN

Emulation (LANE), and MPOA• IP effectiveness: protocol overhead, TCP throughput

obstacles, sender and receiver buffers, RTT and MTU deadlocks, UDP and Client performance

• Performance Improvements and further developments


TheThe ACTS ACTS projectproject EIES EIES

• Definition, implementation, and experimentation of advanced telecommunication services

• Support routine and non-routine communicationbetween different maritime players

• Define and transpose the user requirements for theservice development of EIES

• Build-up a pre-commercial global EIES service• Establish an ATM link between the different

harbour sites (Bordeaux, Bremen, Brest, Santander) to use the prototypes in real life


EIES EIES servicesservices• Computer Supported Cooperative Work (CSCW)• Distribution of multimedia information about

different databases (BluePages and Port EntryGuide)

• Integration of Electronic Data Interchange (EDI) and Electronic Mail (Email)

• Mobile communication (DSRR, DECT, and Inmarsat) for the mobile access to the services.

• Fixed networks: ATM, ISDN, and Internet (IP)


EIES EIES platformplatform

LAN 2

Remote Client

LAN 1

ATM

IP Router

Mobile Access

LAN Client

Internet Server

Internet

Communications Server Communications Server

Mobile Access

LAN Client

Internet Server

Remote Client

IP Router


• Internet Protocol works connectionless (hop-by-hop-transmission)

• No acknowledgements, error- and duplicatedetection with IP

• Data packets are variable: 20 byte - 65 kbyte; destination address identified the other client

• Lost data packets have to repeat requested byhigher layer protocols (TCP)

• Multicast/broadcast functions• Type-of-Service (TOS)

IP IP featuresfeatures


ATM ATM featuresfeatures

• Connection-oriented technologie: virtualconnections will establish for the cell transport(PVC/SVC)

• ATM has its own address structur and routingfunktions

• 53 byte cells with fixed size contain payload and control data

• Point-to-point connections• Quality-of-Service (QoS)


IPIP--overover--ATM ATM AdaptationsAdaptations• Classical-IP

- IETF: RFC-1577- ATM clients use IP

• LAN-Emulation (LANE)- ATM-Forum- Traditional networks use ATM

• Multiprotocol over ATM (MPOA)- ATM-Forum and IETF protocols- Routing mechanisms will be implemented


ClassicalClassical--IPIP (RFC(RFC--1577)1577)• RFC-1577: Classical-IP and ARP over ATM• Logical Link Control Encapsulation: Multiple protocols can

be transported over a single connection (RFC-1483)• VC-Based Multiplexing: Single protocol is transported over

an ATM connection (RFC-1483)• D-MTU: 9180 Byte• PVC/SVC connections• Transport over the AAL-5 layer• Point-to-point connections• Address resolution by central ATMARP server


ClassicalClassical--IPIP architecturearchitecture

ATM

Ethernet

Client 1

Client 2

Server 1ATMARP- ATMARP-

Server 2

Client 1

LIS 1 LIS 2

Router

Control Connection

Data Connection


EncapsulationEncapsulation (RFC(RFC--1483)1483)

header IP payload

LLC0xAAAA03

OUI0x000000

PID0x0800 IP packet

IP packet with LLC-SNAP header PAD

0-47 byte

LengthDetection CRC-32

headerATM

headerATM ATM payloadATM payload

CPI +CPCS-UU

8 byte

48 byte5 byte

3 byte

20 byte 0-9160 byte

20-9180 byte3 byte 2 byte

IP packet

LLC/SNAP packet

IP

28-9188 byte

AAL-5 packet

ATM cells

1-192 cells

48 byte5 byte

SAR-PDU payloadPT SAR sublayer

header

0 SAR-PDU payloadPT

header

0


RFCRFC--1577 1577 conclusionsconclusions

• Advantages:- high data throughput by high MTU (9180 byte)- simple and stabile standard

• Disadvantages:- only IP unicast is supported- high manual configuration effort- no multicast/broadcast support- no redundant ATMARP server- direct connections to other LIS subnets is not possible- no QoS


LAN Emulation (LANE)LAN Emulation (LANE)• Migration of traditional LANs to ATM: Ethernet

switch (layer 2) und router (layer 3) coupling• Universal implementation (MAC layer is emulated):

arbitrary LAN protocols• Using of the application layer without ATM

configuration• Support of PVC/SVC connections• IP multicasting• D-MTU: 1500 byte


LANE LANE architecturearchitectureLAN Emulation Service

LEC

LAN Emulation Configuration

LAN Emulation Server (LES)

Broadcast and Unknown Server

Direct Data Exchange

Control Connection

Configuration Control

SendSendUnicast Multicast

ConnectionConfiguration Control

Connection

Control Connection

LEC

Server (LECS)

Distributed Control Connection Multicast Control Connection

Distributed Data Connection Multicast Data Connection

(BUS)


header IP payload

LLCAA AA 03

OUI00 00 00

PID0800 IP packet

IP packet with LLC/SNAP- and additional LAN encapsulation

0-47 byte

LenghtDetectionCRC-32

headerATM-

headerATM-ATM payload

CPI +CPCS-UU

48 byte5 byte

3 byte

20 Byte 0-1472 byte

20-1492 byte3 byte 2 byte

IP packet

LLC/SNAP packet

IP

44-1516 byte

AAL-Typ5 packe

ATM cell

2-32 cells

48 byte5 byte

PAD

IP packet with LLC/SNAP encapsulation

28-1500 byte

LE-header

DestinationAddress

LANE packet

2 byte 6 byte

SourceAddress

6 byte 8 byte

SAR-PDU payloadPT SAR Sublayer

header

0PT

header

0 SAR-PDU payload

ATM payload

Type/Length

2 byte

LANE LANE encapsulationencapsulation


• Advantages:- integration of traditional networks- transparency for arbitrary network protocols- multicast/broadcast support- automatic configuration

• Disadvantages:- high functionality (layer 2 emulation)- MTU and older network boards limitated throughput- bad scalability- no redundant BUS (overload)- no QoS

LANE LANE conclusionsconclusions


MPOA MPOA capacitycapacity• Support multiple protocols effective over ATM networks• Distribute the routing functions between route servers• Separate routing from switching functions• Leverage performance and QoS capabilities of ATM network• Direct connections between ELANs rather than passing through

traditional routers• Direct Virtual Channel Connections (VCC) between data

forwarding devices• Interworking with unified routers• Enables subnet members to be distributed across the network• Efficient scalability of the ATM network


MPOA MPOA architecturearchitecture

IASGCoordinationFunctional

DefaultForwarderFunctional

Group

Edge Device

Workstation

ATM network

ATM-Host

ATM-Host

Token Ring

Kontrollverbindung

Control Connection

Data Connection

Shortcut

Group

Data Connection

Control Connection

Data Connection

Control Connection


• Multicast Address Resolution Server (MARS)- support of multicasting by additional MARS server

• Next-Hop Resolution Protocol (NHRP)- direct connection between subnets possible

• Resource Reservation Protocol (RSVP)- QoS parameter at connectionsless packets- similar to the UNI signaling

• Private Network-to-Network-Interface (P-NNI)- control data exchange between ATM systems- transparency pass on the virtual connection

ExtensionsExtensions forforMPOA MPOA attemptsattempts


• Advantages:- QoS is supported for the first time- router bottlenecks are eliminated- management of large networks- build up of VLANs

• Disadvantages:- MPOA is not a full defined spezification (1998)- IETF protocols must further developed- scalability is an extremely complex issue- MPOA does not provide a stable network yet

MPOA MPOA conclusionsconclusions


IPoverATMIPoverATM--OverheadOverhead• STM-1-Frame (OC-3): 155,52 Mbps• ATM Layer: 149,76 Mbps• Adaptation Layer AAL-5: 135,632 Mbps• LLC/SNAP encapsulation:

- MTU: 576 byte 126,937 Mbps- MTU: 9180 byte 135,22 Mbps- MTU: 65527 byte 135,563 Mbps

• Internet Protocol (IP): 125,2/135,1/135,6 Mbps• Transport Layer: 120,9/134,8/135,5 Mbps• Application Layer via TCP: 116,5/134,5/135,5 Mbps• Application Layer via UDP: 119,1/134,7/135,5 Mbps


• Socket buffer size at sender/receiver• Network: Maximum Transport Unit (MTU)• Protocol: Maximum Segment Size (MSS)• Sender: using of the Nagle’s algorithm• Round-Trip-Time (RTT)• Receiver: delayed acknowledegements• Sender: Silly Window Syndrom (SWS)• Copy strategy at the socket interface• Network congestion and lost packet notice

TCPTCP--ThroughputThroughput ObstaclesObstacles


Sender and Receiver Sender and Receiver bufferbuffer

S/E 16kbyte

20kbyte

24kbyte

28kbyte

32kbyte

36kbyte

40kbyte

44kbyte

48kbyte

52kbyte

16 kbyte 15,05 13,60 0,322 0,319 0,319 0,467 0,469 0,466 0,469 0,46920 kbyte 15,99 14,60 15,07 14,87 15,40 14,24 1,095 1,095 0,548 0,54924 kbyte 17,71 16,79 16,74 16,32 17,40 17,31 17,42 17,12 0,760 0,74028 kbyte 16,57 17,69 17,93 18,13 18,36 19,20 19,74 19,78 18,38 18,2032 kbyte 14,63 18,96 18,42 19,23 19,14 19,74 19,96 20,31 19,69 19,1736 kbyte 14,33 19,22 18,12 19,82 19,77 19,92 20,56 20,49 20,13 20,2040 kbyte 15,16 19,34 18,85 19,73 20,11 20,41 20,81 20,74 20,69 20,5744 kbyte 14,80 19,40 18,27 20,39 20,16 20,74 20,99 20,87 20,89 20,7048 kbyte 14,62 19,46 18,34 20,48 20,26 20,41 20,85 20,83 20,93 20,8352 kbyte 13,92 19,41 18,26 20,50 20,06 20,21 20,88 20,91 21,21 21,06


RTT and MTU RTT and MTU deadlocksdeadlocks

0

10

20

30

40

50

60

0 5 10 15 20 25 30

RTT [10̂ -3 s]Th

roug

hput

[Mbp

s]

MTU 576 byteMTU 1500 byteMTU 9180 byteTCP-Window-Limit

• MTU of 9180 byte has the best performance ifthe RTT is low

• MTU of 1500 byte has the best performance ifthe RTT is high

• If the MTU is smaller as the used packet size: fragmentation and reassembling isnecessary!


UDP UDP performanceperformance

0

1000

2000

3000

4000

0 10 20

Processor numbers10

-Mbp

s-Et

hern

et [k

byte

]

UDP/IPTCP/IP

• Connectionless structure• UDP has no

acknowledgements, no end-to-end control and no duplicate detection

• Less locking effects forprotect shared protocolstate and data

• Locking Effects limits thedata throughput.


Client Client performanceperformance

1 2 3 4 5 60

50100150200250300350400450

Late

ncy

Tim

e [µ

s]

1 2 3 4 5 6

Sender (1-3) and Receiver site (4-6)

Single-Copy +Checksum

LANs (1,4Ethernet / 2,5FDDI / 3,6 ATM)

• Operation system (inter-processcommunication)

• Data processing• CPU performance• Memory speed• I/O bus bandwidth• ATM adapter

implementation


Client TuningClient Tuning

Classical-IP: Throughput of 134,01 Mbps (Sun20-Ultra)LAN-Emulation, test 1: Throughput of 76,30 Mbps (Sun20-Ultra)LAN-Emulation, test 2: Throughput of 117,63 Mbps (Ultra-Ultra)

• Using of the D-MTU value• Path-MTU: max. possible packet size should be switch on

(none fragmentation)• MSS value: 1436 byte for high speed networks• Sender and receiver buffer at least 2 times bigger than MTU

value• Window Scale Option (RFC-1323) higher Window-Size


......furtherfurther developmentsdevelopments

• Classical-IP, Version 2- distributed ATMARP server

• LANE, Version 2- L-UNI: QoS, multicast, ELAN multiplexing- L-NNI: distributed LES/BUS

• IP-Switching (Ipsilon)- none standard- other proposal Tag-Switching from CISCO

ATM in TCP/IP environment: Adaptations and Effectiveness IP-over-ATM (EXPERT).ppt Folie 2/28 Content...

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