[e2e] Default rwin values

[Mark Allman]

> I am trying to find citable sources for default rwin values on
> different OSes. From what I've found, defaults of 8KB and 16KB are not
> as uncommon as I thought they were. So,
> 
> 1. Can someone tell me current defaults on different OSes? (Maybe a
> citable source even?)
> 
> 2. If default rwin values in use are indeed as low as 8 or 16KB, why is
> that so? Is it sufficient for the most part to have a 16KB rwin? Is
> kernel memory that hard to come by in times when system memory of 1/2
> GB is not unreasonable?

We didn't try to break things out by OS, but there is a distribution of
advertised window values observed in clients that hit our web server in:

    Alberto Medina, Mark Allman, Sally Floyd. Measuring the Evolution of
    Transport Protocols in the Internet. May 2004.
    http://www.icir.org/mallman/papers/tcp-evo-submit.ps

(See figure 6.)

A note: if you compare this with results of a similar analysis around
2000 (found in the following paper) you'll see that advertised windows
are increasing.  It seems to me this likely means that *default*
advertised windows are increasing --- a Good Thing.

    Mark Allman. A Web Server's View of the Transport Layer. ACM
    Computer Communication Review, 30(5), October 2000. 
    http://www.icir.org/mallman/papers/webobs-ccr.ps

allman


--
Mark Allman -- ICIR -- http://www.icir.org/mallman/



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