bandwidth limitation on outgoing strict-priority queue on NCS540, IOS-XR 7.0.2

[MalteHahlbeck]

How do I configure bandwidth limitation on outgoing strict-priority queue on NCS540, IOS-XR 7.0.2?

Excerpt of my qos-configuration:

class-map match-any CLASS_VOICE
 match traffic-class 5 
end-class-map

policy-map EGRESS_QoS
 class CLASS_VOICE
  priority level 1 
  police rate percent 10
! 
 class CLASS_VOICE-SIG
  bandwidth remaining percent 3 
! 
 class CLASS_VIDEO
  bandwidth remaining percent 20 
!
 class CLASS_DATA
  bandwidth remaining percent 50 
! 
 class CLASS_LOW
  bandwidth remaining percent 10 
! 
 class CLASS_NETWORK
  bandwidth remaining percent 5 
! 
 class class-default
  bandwidth remaining percent 10 
! 
end-policy-map
! 
policy-map EGRESS_ SHAPING_PE
 class class-default
  service-policy EGRESS_QoS
  shape average percent 100 
 ! 
end-policy-map

Applying to the interface and commit change:

service-policy output EGRESS_SHAPING_PE
!!% 'DPA_QOSEA' detected the 'warning' condition 'Unsupported action type for egress'

 So, egress policing is not allowed.

 In IOS-XE 16.x.x (ASR907) I can apply the following (working) policy-map with outgoing shaping as above:

policy-map EGRESS_QoS
 class CLASS_VOICE
  priority percent 10
 class CLASS_VOICE-SIG
  bandwidth remaining percent 3 
 class CLASS_VIDEO
  bandwidth remaining percent 20 
 class CLASS_DATA
  bandwidth remaining percent 50 
 class CLASS_LOW
  bandwidth remaining percent 10 
 class CLASS_NETWORK
  bandwidth remaining percent 5 
 class class-default
  bandwidth remaining percent 10

How can I archive a percentive bandwidth limitation on the priority queue? We need this feature to avoid starvation of non-priority-classes in case of congestion.

Regards,

Malte

[smilstea]

https://www.cisco.com/c/en/us/td/docs/iosxr/ncs5500/qos/b-ncs5500-qos-cli-reference/b-ncs5500-qos-cli-reference_chapter_01.html

Policing is in ingress only feature and shaping an egress only feature.

Sam

[MalteHahlbeck]

Yes, that's true. But look at my example regarding IOS-XE. In IOS-XR there is no implicit policier at LLQ-level (as it is in IOS-XE). My question was: how can I archive this?

[smilstea]

You can apply a shaper in the parent and child classes, that would be the most accurate and restrictive measure.

This is what I have seen other customers do with their priority queues. And then bandwidth statements for the queues without priority statements.

Sam

[MalteHahlbeck]

OK, thank you.

I will give it a try in our hard-ware lab. It seems to be a solution, what I have read so far. I will update this thread.

Regards,
Malte

[johnlloyd_13]

hi,

i ran into the same problem in our NCS540 (IOS-XR).

i'm also trying to achieve the same QoS MQC with IOX-XE ASR especially for voice and apply 'priority percent'.

are we limited with 'shaping' in applying 'service-policy output'? will you be kind to share the config you end up using?

RP/0/RP0/CPU0:NCS540#sh run policy-map
Mon Mar 29 08:25:42.053 UTC
policy-map MPLS-OUT-v2
class MPLS-VOICE-v2
bandwidth percent 35
!
class MPLS-CLASS-7-v2
bandwidth remaining percent 5
!
class MPLS-CLASS-6-v2
bandwidth remaining percent 5
!
class MPLS-CLASS-4-v2
bandwidth remaining percent 40
!
class MPLS-CLASS-3-v2
bandwidth remaining percent 20
!
class MPLS-CLASS-2-v2
bandwidth remaining percent 10
!
class MPLS-CLASS-1-v2
bandwidth remaining percent 5
!
class class-default
!
end-policy-map

EDIT - i just tried using 'priority' and 'shape average percent' but still getting a failed config error. can someone please advise how to achieve a similar MQC in IOS-XE as mentioned above by OP.

policy-map MPLS-OUT-v2
class MPLS-VOICE-v2
priority level 1
shape average percent 35