Scaling Routers

I'm going to be honest here. I have no idea what this paper said. Not that it was a bad paper. I think this paper should stay in the syllabus. It's just that I would prefer to have read some more background material on router design so that I had the necessary experience to understand this paper.

That being said, this paper looks like it discusses some upcoming problems in scaling routers to deal with ever-increasing internet traffic, which seems like a good thing to do. Everybody wants their downloads to go faster, from movies and music to software updates. However, the paper seems to assume that in the future, we will have individual routers with lots of packets being pumped through them simultaneously. While I think that's possible, it seems like this router is being designed for high speed links across the continent. With large companies strategically placing caches close to clients, this kind of router may not be necessary. Then again, who knows?

The basic ideas behind this paper are doing very simple, yet elegant load balancing, and simplifying the meshing architecture. In order to get large amounts of throughput, they do a very simple round-robin type of load balancing. At the same time, by using optics to increase the speeds of the links connecting linecards, they are able to reduce the necessary number of links in the mesh.

The paper also introduces an algorithm called Full Ordered Frames First (FOFF) which allows it to guarantee that packets from the same connection are not transmitted out of order. Frankly, this seems like a somewhat silly restriction to put on a router. All of the papers we have read so far in this class have told us that the internet does not guarantee in-order delivery. The author claims that out-of-order delivery can cause unnecessary retransmissions in TCP. While these unnecessary retransmissions seem unlikely give the current implementation of TCP, if it is indeed the case that such a router would misbehave, it seems like the best thing to do would be to modify the TCP protocol.