Re: [tcpm] TCP tuning

[John Heffner <johnwheffner at gmail.com>]

On Wed, Feb 3, 2010 at 3:44 PM, Jerry Chu <hkchu at google.com> wrote:
> Hi John,
>
> On Wed, Feb 3, 2010 at 12:32 PM, John Heffner <johnwheffner at gmail.com> wrote:
>> A couple thoughts:
>> - A large initial window should probably only be used by mutual
>> agreement.  Maybe via a TCP option during the handshake?
>
> This may not be needed. A receiver can effectively constrain the
> sender's window by advertising a smaller initial receive window.
>
> Obviously this works for only the initial window, not the restart window.
> (Oh, on a second thought this can be made to work for the restart
> window too.)

A good point, though most receivers (Linux 2.4 and later being the
exception) advertise all available window space, not expecting a large
initial burst from the sender.  I think you need a negotiation for
opt-in rather than opt-out.

  -John