[j-nsp] Rewriting customer DSCP with MPLS EXP

[Cydon Satyr]

I stumbled upon something I can't get my head around.

I've been doing some CoS testing; it's a simple L3VPN network, and at the
egress PE router,
I want to rewrite customer dscp with whatever exp value I classified from
core interface.

The topology is actually two M320 connected back to back with 4 logical
system.



[C1]---ge-2/0/0-----[PE1]---------------[P1]-----------------[P2]-------------[PE2]----ge-2/0/0----[C2]



PE1 and P2 are first router M320, and P1 and PE2 are second M320 router.
C-routers are separate routers.

Core links are all ge-2/1/0 with .1q tags.


This is config on both routers (logical system's QoS are also in master
instance):

[edit class-of-service interfaces]
ge-2/0/0 {
    unit * {
        forwarding-class REALTIME;
        rewrite-rules {
            dscp RW-dscp;
        }
    }
}
ge-2/1/0 {
    unit * {
        scheduler-map SCM;
        classifiers {
            dscp BA-dscp;
            exp BA-exp;
        }
        rewrite-rules {
            dscp RW-dscp;
            exp RW-exp;
        }
    }
}

my exp classifier:

forwarding-class BE {
    loss-priority low code-points 000;
    loss-priority high code-points 001;
}
forwarding-class REALTIME {
    loss-priority high code-points 101;
}
forwarding-class VIDEO {
    loss-priority low code-points 010;
    loss-priority high code-points 100;
}
forwarding-class CRITICAL {
    loss-priority low code-points 111;
    loss-priority high code-points [ 110 011 ];
}


The customer traffic gets classified in REALTIME with PLP low. The exp
rewrite rule marks outgoing packet with
101.

The issue is this, on all routers I see traffic classified and marked with
101. On the egress PE router, however,
I see traffic classified as VIDEO (which require exp marking of 010 or
100). At the same time the customer receives
traffic marked with 100. It is if for some reason the last router
classified traffic with VIDEO and marked outgoing
dscp with VIDEO.

I can't seem to understand why this is happening. The thing I see is
default exp classification is this:


run show class-of-service classifier type exp name exp-default
Classifier: exp-default, Code point type: exp, Index: 10
  Code point         Forwarding class                    Loss priority
  000                BE                                  low
  001                BE                                  high
  010                REALTIME                            low
  011                REALTIME                            high
  100                VIDEO                               low
  101                VIDEO                               high
  110                CRITICAL                            low
  111                CRITICAL                            high


In default exp classifier, marking of 101 goes to VIDEO, not REALTIME.
But as you can see I have the correct configuration on all interfaces...or
do I?

Why are all routers classifying traffic correctly as REALTIME and marking
101, when the egress PE is
classifying as VIDEO ? The same thing happens in other direction.


I spend couple of days on this and can't seem to figure it out.


Thanks!