[Bloat] TCP TFO client behaviour

[Eggert, Lars]

I suggest you discuss this on tcpm at ietf.org, where TFO is being developed.

Lars

On Dec 11, 2012, at 17:48, Ketan Kulkarni <ketkulka at gmail.com> wrote:

> Hi,
> I am testing tcp tfo behavior with httping client and polipo server.
> 
> One observation from my TFO testing  -If for a connection server sends a
> cookie to client, client always does TFO for subsequent connections. This
> is ok.
> 
> If for some reason, server stops supporting TFO (either because server got
> restarted without TFO support (in my case) or because path changed and the
> nw node is dropping packet with unknown syn option or stripping the
> option), client does not clear up its cookie cache. It always sends data in
> syn and server never acks the syn-data and client retransmits.
> 
> As per kernel code -if syn-data is not acked it is retransmitted
> immediately - with the assumption first syn was dropped (but the assumption
> server stopped supporting TFO might not have been considered)
> 
> My opinion is to flush the cookie for this server and re-attempt the cookie
> "negotiation" on subsequent connection.
> 
> Your thoughts?
> 
> Thanks,
> Ketan
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