lkml.org 
[lkml]   [1996]   [Mar]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: IP: optimize as a router not host
Date
> Umm, yes of course. But selective reject still has advantages. For
> instance, the receiver can tell the sender which range(s) of bytes it's
> missing, whereas with fast retransmit the sender has to remember the packet
> boundaries.

The sender already knows these as it has the packets handy for
retransmission. The BSD one simply spots 3 repeated ack values in a row
and uses that.

> If more than one packet in that sequence is missing, fast retransmit fails
> -- you don't know which packet got lost, you have to wait for the ack, i.e.
> at least one round trip delay for each hole. Selective reject would give
> you one round trip time total.

Quite probably.

> The rule of thumb seems to be that with more than about 10..25% packet
> loss, TCP just doesn't work very well (or not at all, if you want to send
> big files). IMHO, selective reject would increase that number somewhat.

Ask a mathematician. Certainly at 40% loss tcp becomes a bit of a joke.

Alan



\
 
 \ /
  Last update: 2005-03-22 13:36    [W:0.067 / U:1.248 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site