Cisco ASR1006 QoS on pppoe session: Police percent not supported - no bandwidth for percent calculation

Question

I want to perform QoS on specific (or all the) L2TP sessions that establish on ASR1006 router (LNS).

What I have managed already is to set a police at a specific rate for a class that matches access-list 100 with the following code and it is working ok (tried one user and it limits bandwidth to 800 kbps):

class-map match-all class1
 match access-group 100
!
policy-map child
 class class1
  police 800000 100000 100000 conform-action transmit exceed-action set-qos-transmit 1 violate-action drop
policy-map parent
 class class-default
  service-policy child

Now what I want is to set the police cir as a percentage because I want to apply the policy-map on various pppoe sessions with different speed. But when for example I change the police with "police cir percent 50 pir percent 60" I get the following error: police percent not supported - no bandwidth for percent calculation

One user in cisco community suggested the explicit defining with the use of a RADIUS attribute (Cisco-AVPair += "ip:interface-config=bandwidth qos-reference [value]) but I want the value to be discovered automatically every time a session establishes because I am speaking about many L2TP sessions with different connection rates.

Please your help.

Answer 1

What works for us (ASR 1001X) is the following concept (paraphrased config, syntax might be slightly different).

The idea is to have a shaper in the parent class, so the child classes have a reference of what 100% should be in the given context.

On the ASR, we have a handful of parent policies, one each for the bandwidth classes we sell (e.g. 10,20,50,100)

policy-map PMAP_PARENT-50M
 class class-default
  shape average 50M
  service-policy PMAP_CHILD-4CLASS

policy-map PMAP_CHILD-4CLASS
 class CMAP_CLASS1
  priority percent...
 class CMAP_CLASS2
  bandwidth percent... 
 ...
 class class-default
  bandwitdh percent ...

And then the radius server returns an AV pair, matching what the user subscribed for:

Cisco-AVPair = "ip:sub-qos-policy-out=PMAP_PARENT-50M"

To verify, we usually just do

show policy-map interface viX.xx