Subject: Re: multiple Tx queues
To: Erik E. Fair <fair@netbsd.org>
From: Nick Hudson <skrll@netbsd.org>
List: tech-net
Date: 01/08/2004 08:47:49
[fx: tries not to get on his soap box]
On Wednesday 07 January 2004 10:16 pm, Erik E. Fair wrote:
> At 8:32 -0800 1/7/04, Jason Thorpe wrote:
[...]
> >Could utilize packet tags to map IP TOS, maybe?
[...]
> I thought the IETF explicitly deprecated the TOS bits a while ago?
> There was a proposal to reuse at least one of them for a "congestion
> experienced" bit...
Its now called DSCP see rfc2474 and rfc3260
The congestion stuff appears in rfc3168
> I do remember that the main reason the TOS bits were thought to be
> silly to implement was that if you really want to support N paths
> with different TOS parameters to the same destination, you end up
> (worst case) multiplying the size of the routing table by N for each
> destination net that has different TOS parameters. Given the pressure
> to keep routing table sizes down to something manageable, this was
> thought not to be wise.
I don't see this as necessary. In fact in most cases traffic should/will
follow the same path A->B. Its all about how its treated at each queueing
point.
Nick