details in design ip/dtm

AIMS WorkshopHeidelberg, 9-11 March 1998

© 1998 Net Insight AB

Details in design IP/DTM

Mattias Holmlund

Net Insight AB

[email protected]



Outline

• DTM

• IP over DTM

• Scalability

• DTM LAN Emulation



DTM

Dynamic synchronous Transfer Mode



DTM

• Dynamic synchronous Transfer Mode

• Time Division Multiplexing

• 125 s frames

• 64 bit slots

• Connection Oriented

• Unidirectional channels, n*512 kbps



DTM Multiplexing Format

• 1 Gbps -> 1900 slots/frame

• 2.5 Gbps -> 4800 slots/frame

• Control slots / Data slots

C o ntro l slo ts D ata s lo ts

6 4 -b it s lo ts

1 2 5 s fram es



Switch Node Interconnection

A S1

S2 B



DTM Services

+ High bandwidth

+ Renegotiable CBR

+ Multicast

+ Low latency and jitter

+ Billing

- Connection set-up time



IP over DTM



IP over DTM

• Take IP characteristics into account

• Use DTM to the maximum

• Scale with DTM



IP Characteristics

1

10

100

1,000

10,000

100,000

1 10 100 1,000 10,000 100,000

Flows

Pac

kets

per

flo

w

dnshttp

ip

ftpdata

gre

http-proxy

Quake

ICMP TIMXCEED

Traffic trace from Fix-West, June 1997



Logical IPOD Structure

A

BH

C D

GF

E

DTM



Shortcut Establishment

DTM NetworkA

B

C D

E

F

G

H1

44

4

3

2

5

X ...



When to establish shortcuts?

• QoS flows

• High bandwidth flows

• (Multicast flows)



MPOA vs. IPOD

• Similar in principle

• Both use NHRP

• NHRP Caching

• Differences ATM / DTM

• MPOA based on LAN Emulation



Scalability



Scalability of DTM

Simplicity!

• No priority queuing

• No data processing

• No buffer overflows



Scalability of IPOD

• Relieve routers from

- QoS flows- High bandwidth flows

• Add routing resources when needed



DLE

DTM LAN Emulation



DTM LAN Emulation (DLE)

D L E S e rv e r

E th e rn e t

E th e rn e t

D L E C lie n t

D L E C lie n t

D L E C lie n t

DTM



IPOD and DLE

E th e rn e tE th e rn e t

E th e rn e tE th e rn e t

R 2 R 1R 3

L A N 1L A N 2

C

D

A

F 2

F 1



ConclusionsDTM

• Renegotiated CBR

• Cost efficient, Scalable

IP network with support for

• High bandwidth

• QoS



More Information

http://www.netinsight.se

Mattias Holmlund

[email protected]

details in design ip/dtm

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