[c-nsp] QoS Order of Operation in an MPLS environment

[Oliver Boehmer (oboehmer)]

Yasser,

>   I would like to know what is the order of operation for QoS inside a
> PE-router.
> 
> For the incoming packets from CE to PE router, inside the PE, will the
> packet tagged with the MPLS EXP once entered the VRF, or I will match
> and set ip prec values and PE will automatically translate it to the
> MPLS world inside the Provider core network.

On the VRF interface, you will match on the IP packet (i.e. no label).
By default, when we push labels to send this packet over the MPLS cloud,
the first three bits of the DSCP value is copied into all label's EXP
bits. If you want to change the MPLS EXP bits, you would do so within
the ingress policy-map.

> Any links elaborating this are highly appreciated.

take a look at http://www.cisco.com/warp/public/105/diffserv_tunnel.html
which gives an overview of the various QoS modes (uniform, pipe,
short-pipe) in an MPLS network.

	oli