Nested QoS

paris2london · ‎07-21-2008

I have the following config

class-map match-any L_QOS

match access-group name L_BTS

class-map match-any E_QOS

match access-group name E_BTS

class-map match-any voip-sat

match ip dscp ef

policy-map sat-qos-child

class voip-sat

priority percent 33

class class-default

fair-queue

policy-map sat-qos-parent

class E_QOS

shape average 96000

service-policy sat-qos-child

class L_QOS

shape average 128000

service-policy sat-qos-child

I have applied the sat-qos-parent to the s2/1 interface.

interface Serial2/1

ip address 192.168.xxx.xxx 255.255.255.252

service-policy output sat-qos-parent

When I check the policy-map on the interface, I dont get any matches for the voip-sat class, however I do get the traffic shaping as specified.

Any ideas as to why?

sh policy-map int s2/1

......

Service-policy : sat-qos-child

Class-map: voip-sat (match-any)

0 packets, 0 bytes

5 minute offered rate 0 bps, drop rate 0 bps

Match: ip dscp ef

0 packets, 0 bytes

5 minute rate 0 bps

Queueing

Strict Priority

Output Queue: Conversation 24

Bandwidth 33 (%)

Bandwidth 31 (kbps) Burst 775 (Bytes)

(pkts matched/bytes matched) 0/0

(total drops/bytes drops) 0/0

Class-map: class-default (match-any)

32820 packets, 26876527 bytes

5 minute offered rate 95000 bps, drop rate 0 bps

Match: any

Queueing

Flow Based Fair Queueing

Maximum Number of Hashed Queues 16

(total queued/total drops/no-buffer drops) 11/0/0

Class-map: class-default (match-any)

15220 packets, 1012103 bytes

5 minute offered rate 0 bps, drop rate 0 bps

Match: any

.....

lee.reade · ‎07-21-2008

Hi,

When doing shaping with nested qos, the child policy only gets used when there is congestion on the interface, as specified by the parent policy map, shape commands.

You must use the class-default class on the parent policy, and speciy your shaping contraints on this, then match the child policy map.

IE.

policy-map ptop

class class-default

shape average 128000

service-policy sat-qos-child

class-map match-any voip-sat

match ip dscp ef

policy-map sat-qos-child

class voip-sat

priority percent 33

class class-default

fair-queue

interface Serial2/1

ip address 192.168.xxx.xxx 255.255.255.252

service-policy output ptop

HTH

LR

paris2london · ‎07-22-2008

Hi LR

Thanks for that.

How do I distinguish between different sites?

For instance in my config L_QOS and E_QOS. These class-maps reference different access-lists.

Thanks

lee.reade · ‎07-22-2008

Hi,

You just create the individual class-map and match it in the child policy map.

The idea is that the child policy map does not get called upon, until there is congestion on the inteface, when there is congestion, then the packets are treated as per the child policy, ie you can give voip traffic from one site 32k, voip from other site 32k, and then class default for everything else..

HTH

LR

lee.reade · ‎07-22-2008

Hi,

You just create the individual class-map and match it in the child policy map.

The idea is that the child policy map does not get called upon, until there is congestion on the inteface, when there is congestion, then the packets are treated as per the child policy, ie you can give voip traffic from one site 32k, voip from other site 32k, and then class default for everything else..

HTH

LR

paris2london · ‎07-22-2008

Hi LR,

Thanks for your quick response.

Could you please give me an example...

lee.reade · ‎07-22-2008

Hi,

IE.

policy-map ptop

class class-default

shape average 128000

service-policy sat-qos-child

class-map match-any voip-site1

match access-group 101

class-map match-any voip-site2

match access-group 102

policy-map sat-qos-child

class voip-site1

priority percent 33

class voip-site1

priority percent 33

class class-default

fair-queue

interface Serial2/1

ip address 192.168.xxx.xxx 255.255.255.252

service-policy output ptop

HTH

LR

paris2london · ‎07-22-2008

Would something like this do the trick?

class-map match-all voip-qos-e

match access-group name E_BTS

match ip dscp ef

class-map match-all voip-qos-l

match access-group name L_BTS

match ip dscp ef

policy-map sat-qos-child

class voip-qos-e

priority percent 33

class voip-qos-l

priority percent 33

class class-default

fair-queue

policy-map ptop

class class-default

shape average 128000

service-policy sat-qos-child

I'm assuming that all sites will get the same 128000 shaping.

lee.reade · ‎07-22-2008

Hi,

Yep looks good!

Yes correct, the shaping applies to all sites, but only when you have congestion, ie are sending more than 128000, when that happens traffic is de-queued as per the config in the child policy, LLQ for voip and BE for class default.

HTH

LR

paris2london · ‎07-22-2008

Just to make sure the policy will shape each site to 128000, not the overall bandwidth?

lee.reade · ‎07-22-2008

hi,

the shape average will shape all traffic to 128000, so both sites will be subject to this.

What is your bandwidth on the pipe to where you are sending this voip traffic?

HTH

LR

paris2london · ‎07-22-2008

I have 1Mps aggregate connection and 128k to each site.