Re: Why is my gigabit ethernet so slow?

["Aaron J. Grier" <agrier%poofygoof.com@localhost>]

On Wed, Jan 27, 2010 at 09:03:14PM -0500, Steven Bellovin wrote:
> Sack is mostly of benefit on LFNs (Long, Fat, Networks).  On a LAN or
> pair of LANs, it won't matter much, I suspect.  SACK is "selective
> acknowledgment" -- it can resend just the missing segments, rather
> than everything from the missing segment on forwards.  But that's only
> of interest if there are packet drops, and with few routers, little
> congestion, and steady-state sending, those more or less should not
> happen very often.

I wonder if it would make sense for the kernel to keep a list of
networks to disable SACK on, or look at TTL values to determine that.

-- 
  Aaron J. Grier | "Not your ordinary poofy goof." | 
agrier%poofygoof.com@localhost