[e2e] Are Packet Trains / Packet Bursts a Problem in TCP?

Detlef Bosau detlef.bosau at web.de
Wed Sep 27 08:33:35 PDT 2006

Is this really a NIC problem or end point problem?

When I read Fred´s post yesterday, I got the impression that it´s more a 
problem that flows tend not to interleave on the path. And that´s my 
observation from quite a few NS2 simulations as well (although I didn´t 
do any simulations during the last month, the more simulations I did, 
the less sense I saw in doing so for quite a couple of reasons). Fred 
mentioned that flows  do not behave "TDM like". And if this is the / one 
issue, I´m curious whether this could be changed. I spontaniously 
thought in the direction of "Rate Allocating Servers" (introduced by 
Keshav IIRC), but even if we totally ignore the question how a correct 
rate is to be set for the moment, will this scale up to thousands, 
perhaps millions of flows?

Katsushi Kobayashi wrote:
> I presented a sample NIC implementation for fine
> grained packet pacing:
> http://www.hpcc.jp/pfldnet2006/paper/s3_01.pdf
> In my experience fine grained pacing is easy and small
> foot-print size compared with complete TCP offload.
> Also, I believe NIC vendor is already aware packet pacing
> effect as:
> http://data-reservoir.adm.s.u-tokyo.ac.jp/lsr-20041225/
> I2 will not approve the result using a special hardware.
> So, I believe Chelsio implemented packet pacing feature in
> released product.
> -- 
> Katsushi Kobayashi

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