Tuesday, September 23, 2008

Scaling Internet Routers Using Optics (Stanford '03)

The paper goes very in-depth in designing a 100Tb/s router. It argues for a multi-stage over single-stage design, even though signle-stage is simple. The paper specifically proposes adding a load-balancing stage that randomize the input packets before entering the VOQs. It proposes Full Ordered Frames First (FOFF) to correct mis-sequencing of packets.

The concept of partitioning a switch into multiple stages is very novel. It's similar to pipelining in a circuit. Specializing individual stages of work increase throughout. However, partitioning a switch is at a more macro level. I wonder if there is any formal study in the design of the partitioning? What are the different ways to do the partitioning? What are some of the factors that drive the division?

The paper also suggests decentalized schedulers. This increases scalability and fault tolerance. But it's not clear how this is done. The discussion about the use of optics and MEMS is also too brief for me. I would be interested in reading some follow-up papers on these topics.

I agree that the paper lacks results and evaluation. It focuses a lot on certain design details, which make it hard to understand. This is the first paper i read from this class that i feel lost, which happens very often for my other classes=). On the up side, i did get a chance to google many things i didn't know about router design.

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