Need the most basic outbound QoS policy on NCS5500

[7tsommer]

Hi,

I'm growing increasingly frustrated trying to implement the simplest possible outbound QoS policy on an NCS5500 running 24.1.1. 

All I need is to be able to set CoS outbound on a bundle subinterface. All outbound traffic on that subinterface needs to have its CoS set to 1. Here is a config that represents the extent of what I'm trying to do:

interface Bundle-Ether201
 description OLT1-399-LAB LAG
 mtu 9216
 lacp period short
 lldp
  transmit disable
 !
 flow datalinkframesection monitor SFLOW_MONITOR sampler FLOW_SAMPLER-1-4000 ingress
!
interface Bundle-Ether201.699930 l2transport
 description AE Biz Customer vlan 930 (s-tag 699)
 encapsulation dot1q 930
 rewrite ingress tag push dot1q 699 symmetric
 mtu 9212
 service-policy output MARK_COS1
!
policy-map MARK_COS1
 class class-default
  set cos 1
 ! 
 end-policy-map

However, when the above is applied, I see no CoS (PRI) markings in Wireshark on traffic coming out of that interface on that vlan 930. Everything still has PRI=0.

While the above config is as basic as it gets, I have tried an exhausting number of things, like matching on anything I could think of (there's no QoS anywhere else on this box, so there are no qos-groups or traffic-classes set on any other interfaces) and including some kind of queuing policy (both with default-class and on a variety of other class matches). Nothing I did would show anything but PRI=0 on frames coming out of that interface on that vlan. 

Can anyone help me figure out how to simply set CoS outbound on a subinterface? That's all I need!

[7tsommer · Accepted solution]

I believe I found the problem. I saw in the documentation that setting CoS on subinterfaces that do push/swap rewrites on vlan tags is not supported. I changed up our configs to push the outer tag further downstream and just set the subinterface to expect dual-tagged frames and do no rewrites. This appears to have allowed us to mark CoS on outbound frames.