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Adding QoS for video phone to existing policy

wilson_1234_2
Level 3
Level 3

I have an existing qos policy for our branches and main site. We are implementing video phones in our branches and I have a few questions on how to best implement the qos

The branch config is as follows, currently the voice and data is in the same class of voice:

class-map match-all DATA-Priority

match access-group 111

class-map match-all VOICE

match access-group 110

!

!

policy-map P-QoS

class VOICE

priority percent 21

set dscp ef

class DATA

bandwidth percent 5

set dscp af31

class class-default

set dscp default

fair-queue

random-detect

The phones for our company are matched on access-list 110.

Access-list 111 is actually an application that the remote branches use that connects to a host in the main site.

Going by the Cisco 8 class design model,

dscp af31 is actually classed for voice control traffic.

My questions are these:

Would it be beneficial to change the policy so that the data priority queue dscp af31 is used for voice signaling?

There does not seem to be any poor qulity calling at the moment, but we are not using the video phones yet.

The 8 class model is a little more detailed than I need, I am thinking I could do something like the following:

class-map match-all Voice

match ip dscp ef

class-map match-all Interactive Video

match ip dscp af41 af42

class-map match-any Call Signaling

match ip dscp cs3

match ip dscp af31

class-map match-all Critical Data

match ip dscp af21 af22

class-map match-all Bulk Data

!

policy-map WAN-EDGE

class Voice

priority percent 18

class Interactive Video

priority percent 15

class Call Signaling

bandwidth percent 5

class Critical Data

bandwidth percent 27

random-detect dscp-based

class Bulk Data

bandwidth percent 4

Could someone provide some input?

Also, how do the classes in the cisco model match the traffic if they are not usong access-lists?

20 Replies 20

You may want to try understanding what the provider is doing.

They have a policy that more or less equates to this:

class-map match-any CLASS-EF

match dscp ef

policy-map GOLD-POLICY

class CLASS-EF

priority 1544

class class-default

All they are matching is EF. Here, any packet can be marked EF, and they'll (theoretically anyway) prioritize it.

If you wanted your web traffic to not be dropped, you could do this:

class-map match-any web-traffic

match protocol http

policy-map do-not-drop-web-traffic

class web-traffic

set dscp ef

You should note that most video traffic is going to be marked AF41 or CS4 by default.

If you have a 1.544 Mb link, and they're giving you 1.544 Mb of Gold CAR, then you would want to mark everything as DSCP EF so none of your traffic gets marked. Basically - you would want to maximize it by using as much of the available CAR as possible without going over.

hth,

nick

Sorry nic, I thought I did understand what they were doing.

I didn't understand how to manipulate our policy to best utilize how they had theirs set up.

Maybe you mentioned this earlier, but I didn't "see" what you were saying until just now, which is why I ask all these questions.

Even though it may be frustrating for you, it really does help alot, and is greatly appreciated.

So, I can call voice video and voice signaling all as ef, match by access list and it all should get prioritized.

Thanks for all of your time and assistance in this.

That sounds about right.

It's no problem - glad to help.

-nick

Per your post above:

"You should note that the policy map is order-specific. If you have a class matching dscp af31 above another class matching dscp af31, the class lower in the policy map would not ever match on that."

Won't this prevent me from doing what I had suggested?:

class-map match-all DATA-Priority

match access-group 111

class-map match-all VOICE

match access-group 110

class-map match-all VIDEO

match access-group 109

!

!

policy-map PEFCU-QoS

class VOICE

priority percent 13

set dscp ef

class VIDEO

priority percent 29

set dscp ef

class DATA-Priority

bandwidth 128

set dscp ef

class class-default

set dscp default

fair-queue

random-detect

That all depends on what is in your access lists.

Ok,

I hope this has not been a bad experience for you and you will no steer clear from another other question I may have in the future.

so that comment is only if the match is made by default TOS marking and not when you define the marking and match access-lists?

Is that correct?

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