CS 740: Advance Computer Networks

1

• CS 740 Advance Computer Networks
• Hand-out on Router Design
• 02/07/2007

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ISLIP Scheduling Example
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ISLIP (cont.)
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What Limits Router Capacity?
Approximate power consumption per rack
Power density is the limiting factor today
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Multi-rack Routers Reduce Power Density
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Question

• Instead, can we use an optical fabric at 100Tb/s
  with 100 throughput?
• Conventional answer No
• Need to reconfigure switch too often
• 100 throughput requires complex electronic
  scheduler.

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If Traffic is Uniform
R
In
R
In
R
In
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Two-stage Load-Balancing Switch
R
R
R
R/N
R/N
Out
In
R/N
R/N
R/N
R/N
R/N
R/N
R
R
R
In
R/N
R/N
R/N
R/N
R/N
R/N
R
R
R
R/N
R/N
In
R/N
R/N
Load-balancing stage
Switching stage
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R
R
In
R/N
R/N
1
R/N
R/N
3
R/N
R/N
R/N
R/N
R
R
In
2
R/N
R/N
3
R/N
R/N
R/N
R/N
R/N
R
R
R/N
In
3
R/N
R/N
3
10
Static WDM Switching
Array Waveguide Router (AWGR) Passive
andAlmost ZeroPower
A
B
C
D
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100 Tb/s router Linecard Dataflow
In
l1
l1, l2,.., lN
R
R
WDM
lN
1
3
1
1
1
1
2
3
4
1
1
1
1