Subject: Re: NFS problem.
To: Michael van Elst <mlelstv@serpens.de>
From: Steven M. Bellovin <smb@cs.columbia.edu>
List: current-users
Date: 12/10/2005 09:07:54
In message <dne4vq$qbc$1@serpens.de>, Michael van Elst writes:
>tron@zhadum.org.uk (Matthias Scheler) writes:
>
>>Yes, but it hasn't changed and never will. Large UDP packets are sent
>>as IP fragments. If you lose one of the IP fragments the whole UDP
>>packet is lost because there is no selective retransmit. When a machine
>>e.g. loses 5% of incoming packets at least one of the IP fragments
>>of a 32KB UDP packet will always get lost. Retries will not help because
>>another single lost packet will prevent the reception of the UDP packet.
>
>On the other hand, TCP isn't exactly fast with 5% packet loss either.
>
Right, but TCP adapts its sending rate to the level that avoids packet 
loss.

		--Steven M. Bellovin, http://www.cs.columbia.edu/~smb