923Mbits/s across the ocean

Sun Mar 9 16:29:16 UTC 2003

Also as the OS's are shipped they come with small default maximum window sizes (I think Linux is typically 64KB and Solaris is 8K), and so one has to get the sysadmin with root privs to change this. 

-----Original Message-----
From: Iljitsch van Beijnum [mailto:iljitsch at muada.com] 
Sent: Sunday, March 09, 2003 5:25 AM
To: Joe St Sauver
Cc: nanog at nanog.org
Subject: Re: 923Mbits/s across the ocean

On Sat, 8 Mar 2003, Joe St Sauver wrote:

> you will see that for bulk TCP flows, the median throughput is still 
> only 2.3Mbps. 95th%-ile is only ~9Mbps. That's really not all that 
> great, throughput wise, IMHO.

Strange. Why is that? RFC 1323 is widely implemented, although not widely enabled (and for good reason: the timestamp option kills header compression so it's bad for lower-bandwidth connections). My guess is that the OS can't afford to throw around MB+ size buffers for every TCP session so the default buffers (which limit the windows that can be
used) are relatively small and application programmers don't override the default.