[c-nsp] Preserving CoS with xconnect on ME3600X

[Lobo]

Hi everyone.  I was hoping I could get some help with an EoMPLS config 
I'm working on between an ME3600X and an ME6524 and being able to 
preserve the CoS field values.

The xconnect pseudowire it actually up and able to pass traffic so 
that's not a problem.  The issue is that any CoS values I assign to the 
data packets seem to get overwritten on the ME3600X in the service 
instance config.  This is a rough topology of what I'm using:

Traffic generator --- 3750 --- ME3600X ---pseudowire over mpls cloud--- 
ME6524 --- 3750G --- Traffic generator

What I see happening (going from left to right) is that the 3 different 
CoS values (5,3,0) all get overwritten to zero as soon as the traffic 
goes over the xconnect.  LDP labels are also sent as exp zero.

In the opposite direction where the xconnect starts on the ME6524, the 
CoS values are copied over to the exp values all the way to the ME3600X 
until it passes through the service instance config.  Once I inspect the 
traffic on the 3750 switch, I see all my traffic arriving with CoS 0.  
Note that DSCP is preserved in both directions.

I'm curious if there is some global command for the ME3600X or some 
additional config that I need to do on the service instance in order to 
somehow copy the CoS value to EXP bit.  Or do I have to do more 
inspection and writing of values via MQC?

Here is the config I have for the xconnect on the two platforms.

ME3600X

interface GigabitEthernet0/8
  switchport trunk allowed vlan none
  switchport mode trunk
  load-interval 30
  speed 100
  duplex full
  service instance 3801 ethernet
   encapsulation dot1q 3801
   rewrite ingress tag pop 1 symmetric
   xconnect 172.28.110.2 666 encapsulation mpls
  !

ME6524:

interface GigabitEthernet1/1.3801
  encapsulation dot1Q 3801
  xconnect 172.28.110.2 666 encapsulation mpls
!

Thanks!

Jose

P.S. I've done xconnects with two 6524s as the PEs and they always 
preserve the correct CoS values and apply the appropriate exp bit values.