Train wreck (was "Does TCP Need an Overhaul?")

Mon Apr 7 16:18:21 UTC 2008

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On Apr 7, 2008, at 8:36 AM, Lucy Lynch wrote:
> Anyone out there attend this event?
>
> The Future of TCP: Train-wreck or Evolution?
> http://yuba.stanford.edu/trainwreck/agenda.html
>
> how did the demos go?

The researchers demonstrated four things that made sense to me:

(1) TCP is not the right transport for carrying video data if what  
you want is real-time delivery. Carrying stored video (YouTube-style)  
is fine, but if you're trying to watch TV, you really should be using  
some other transport such as RTP or DCCP. Same comment holds for  
sensor traffic, but the astronomers who carry radiotelescope data  
halfway around the world weren't present.

(2) TCP is probably not the right protocol for carrying transaction  
traffic within a data center. One speculates that SCTP (which has a  
concept of a stream of TCP-like "transactions" that can be handled  
out of order and allows for congestion management both within and  
among transactions) might be a better protocol, and in any event that  
when thousands of transactions back up in a gigabit Ethernet chip's  
queue on a host that the host should start noticing that they are  
experiencing congestion.

(3) 802.11 networks experience not only the traditional congestion  
experienced in wired networks, but channel access congestion (true of  
shared media in general) and radio interference. In such networks, it  
may be useful to think about congestion as happening "in a region" as  
opposed to "at a bottleneck".

(4) When it is pointed out that instead of complaining about TCP in  
cases where it is the wrong protocol it may be more useful to use the  
transport designed for the purpose, researchers who presumably are  
expert on matters in the transport layer respond in complete surprise.
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