[nsp] IP QoS with FR/ATM?

[Tom Scott]

JJ,

I may not understand your question even now. But as a last resort, may I 
refer you to the informal management model in RFC 3290. According to that 
model there is only one level of queueing: at the interfaces before or after 
the packets enter the routing fabric (see the RFC for the definition of 
"routing fabric"). But that is only a model for the purposes of developing 
the diffserv protocol. For all I know, a router manufacturer might implement 
the diffserv model with multiple levels of queueing, but it seems to me that 
that would be very inefficient. Maybe our friends from Cisco can tell us 
what they've learned in their hardware internals classes? 

-- TT

JJ wrote:
> 
> Tom,
> 
> That was not what I was asking for.
> 
> I am trying to figure out if I have IP QoS and ATM/FR
> traffic shaping, does IOS first put the packets into
> ip queues and then move them into ATM/FR queues?
> 
> If this is true then there must be two sets of
> buffers/buckets, but I never seen a diagram like this
> from any cisco docs. In the book IP QoS from cisco
> press, the author does not describes this in detail,
> just mentions something like pvc queueing and you can
> user different shemes like cbwfq or priority queueing,
> but never says if there are two level of queues or
> just one?
> 
> thanks
> 
> jj
> 
> --- Tom Scott <telecomtom@vedatel.com> wrote:
> > J,
> >
> > You could be asking about the mechanics of how the
> > cells, frames and packets
> > get "marked". I don't know if Cisco has shared that
> > with us (customers). But
> > I remember finding something about L3-to-L2 QoS
> > mappings in one of the many
> > CCO docs I've browsed, and I even put the chart on a
> > wall, something like
> > this:
> >              L2     L3 IP         L3
> >              CoS    Precedence    DSCP
> > voice RTP    5      5             EF
> > voice RTCP   3      3             AF31
> > video        4      4             AF41
> > data         0-2    0-2           0-AF23
> >
> > Beware of typos.
> >
> > -- TT
> >
> >
> > JJ wrote:
> > >
> > > Trying to emphasis my confusion:
> > > since the atm/fr vcs have cbr, vbr or cir, so they
> > > must have queues per pvc for cells or frames, ip
> > qos
> > > such as CBWFQ has queues for different classes of
> > ip
> > > packets, how do they work together?
> > >
> > > Thanks
> > >
> > > --- JJ <yulingna@yahoo.com> wrote:
> > > > Date: Tue, 8 Oct 2002 20:17:26 -0700 (PDT)
> > > > From: JJ <yulingna@yahoo.com>
> > > > Subject: IP QoS with FR/ATM?
> > > > To: cisco-nsp@puck.nether.net
> > > >
> > > > I am trying to understand how ip qos works with
> > FR
> > > > and
> > > > ATM.
> > > >
> > > > I read that both FR and ATM do per vc queueing,
> > is
> > > > this true?
> > > >
> > > > If I configure CBWFQ udner one fr or atm pvc,
> > does
> > > > the
> > > > router have two sets of queues? one set for
> > > > different
> > > > classes of ip packets, after the ip packet got
> > > > dequeued from the ip layer, they will be queued
> > > > again
> > > > under that pvc? is it same for fr and atm?
> > > >
> > > > I can not find anything from cco, all of the qos
> > > > docs
> > > > either explain ip qos or atm/fr qos.
> > > >
> > > > thanks for any help.
> > > >
> > > > JJ