Subject: [tcpm] Initial Window units.

From: "Anantha Ramaiah (ananth)" <[email-masked]>
Date: Fri, 30 Mar 2012 04:02:37 -0700

Hi,

    I had brought this question to Jerry offline.  TCP communicates
receive window in bytes (sliding window is based on bytes) So, it would
be useful to have the initial window as bytes. Oh, yeah the "bytes
versus packet" argument again J Is that an issue? Maybe not but with
larger IW's it probably would..

    Consider the case of IW=10, and the stack doesn't do PMTU, then we
end up putting more segments on the network, in case of fragmentation in
the path). Even with PMTU,  PMTU convergence takes time and it can
complicate things.  Would it be useful to list this relationship and
recommend a lesser IW if the MSS > 1500?  In such cases the # of bytes
would be useful metric.  Another point in favor of this thought would be
that Jerry mentioned that anything above than IW=10 wasn't that useful
for many web objects.. so having  IW in bytes versus packets seems
useful.  Basically I am nervous about the high watermark (cap) of IW in
packets, would think it is safer if bytes were used instead.

-Anantha