Re: [leo@yuriev.ru: [PATCH] ethernet-bridge: update skb->priority in case forwarded frame has VLAN-header]

[jamal <hadi@xxxxxxxxxx>]

On Mon, 2005-03-07 at 18:53, Patrick McHardy wrote:
> jamal wrote:
> >>
> >>The priority should still start at 0. You don't want to create a 16-band
> >>queue just to have 8 bands unused.
> > 
> > 
> > say what?;-> Nothing has to start at 0. 16 priorities does not equate to
> > 16 queues. 
> 
> Right. But the default pfifo_fast/prio mapping maps the upper 8 values
> to queue 1, which seems to make this effort kind of useless. 
> I don't know if the default-mapping of the lower 8 values is useable 
> in this context, 

Indeed that looks bad. But wouldnt have helped if we started at 0
either. You need monotonically increasing values to make proper
sense. So i suppose to do proper qos with L2, one must install the prio
qdisc and rewrite the priomap.

The mapping used in pfifo_fast is derived from RFC1349 4 bit TOS which
is really considered toast these days. We need to revamp things - but
this would require some surgery in the route code as well (so maybe safe
to leave as is).

> I need to inform myself more on this subject (thanks for the
> IEEE vs. IETF pointers).
> 

Has bitten me a few times when trying to do Qos between switches and
routers.

cheers,
jamal