02-25-2009 04:58 PM - edited 03-17-2019 09:39 PM
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?
03-03-2009 06:22 AM
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
03-03-2009 07:47 AM
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.
03-03-2009 08:37 AM
That sounds about right.
It's no problem - glad to help.
-nick
03-03-2009 08:47 AM
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
03-03-2009 08:54 AM
That all depends on what is in your access lists.
03-03-2009 08:58 AM
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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