NCS 55A2 XR 6.6 QoS

[Seth Beauchamp]

I am trying to do a simple shaper with a basic scheduler to prioritize EF traffic across a link. With the policy that I have tried, I get an error upon commit "!!% 'DNX_QOSEA' detected the 'warning' condition 'Invalid egress policy, Cannot have both queuing & marking in the same policy'"

The policy is:

interface TenGigE0/0/0/0.102
 service-policy output WAN_SHAPE_1Gbps

policy-map WAN_SHAPE_1Gbps
 class class-default
  service-policy WAN_TRAFFIC
  shape average 990 mbps 
 ! 
 end-policy-map


policy-map WAN_TRAFFIC
 class PRIORITY
  priority level 1 
  police rate percent 95 
  ! 
  ! 
 class class-default
 ! 
 end-policy-map

class-map match-any PRIORITY
 match qos-group 1 
 end-class-map

I also have an inbound policy on another interface which matches dscp EF and sets QoS group 1.

So the question is.. why does the error suggest this policy has both queuing and marking? 

Also should I be setting/matching traffic-class instead of Qos-Group? Whats the difference between the two?

[smilstea]

Hi Seth,

A few things, qos-group matching on egress counts as a marking action and queuing and marking are not supported at the same time. On NCS5500 we have to apply different service-policy statements on the interface for queuing and for remarking actions. This means separate policy-maps  have to be created for marking and queuing respectively.

NCS5500 implements a different concept for marking. It is based on traffic-class and qos-group. On egress we match on these two parameters to remark traffic and to select queues.Traffic-class determines priority through the fabric.

While “match traffic-class” has to be used for queuing features “match qos-group” can only be used for marking.

Another issue is that policing is only supported on ingress and shaping only supported on egress.

Thanks,

Sam

[Seth Beauchamp]

Thanks for the response. If I may ask a follow up...

What would be the simplest way to ensure EF traffic gets prioritized with a low latency queue on these devices? Essentially, I have the NCS 55A2 positioned as a P router and want to ensure EF traffic (or mpls exp 5) gets LLQ treatment outbound.

on the ingress ports, do I need a marking policy that sets sets traffic class using a class-map matching dscp ef and mpls exp 5? Then a policy on egress matching the traffic-class? Does the dscp EF and mpls exp 5 markings stay preserved after leaving NCS 55A2 with this method?

This for example?

class-map match-any ef
 match traffic-class 1 
 end-class-map
! 
class-map match-any tc1
 match dscp ef 
 match mpls experimental topmost 5 
 end-class-map
! 

policy-map egress
 class class-default
  service-policy priority
  shape average 990 mbps 
 ! 
 end-policy-map
! 
policy-map priority
 class ef
  priority level 1 
 ! 
 class class-default
 ! 
 end-policy-map
! 
policy-map ingress
 class tc1
  set traffic-class 1
 ! 
 class class-default
 ! 
 end-policy-map
! 

interface te0/0/0/0
 service-policy output egress

interface te0/0/0/1
 service-policy input ingress

[smilstea]

The markings should stay preserved, for the sake of queuing we need to use traffic-class on ingress and egress. I seem to recall something about needing to use both qos-group and traffic-class on ingress but I can't find those details at the moment.

Sam