qos for gateways

[reidg]

can someone explain to me how/where/if the incoming calls to a gateway have dscp/precedence applied.

I see within Clusterwide Parameters under services, on CCM that there are settings there, but are these automatically applied to calls coming in via a gateway, or is this something I need to do on each individual gateway.

thanks

[dgahm]

Grant,

The router will mark the packets according to the IOS defaults. You should not have to do anything unless you wish to use something different. For MGCP show mgcp will display the values being used:

MGCP media (RTP) dscp: ef, MGCP signaling dscp: cs3

For H323 you have to look at individual dial peers:show dial-peer voice XXX

ip media DSCP = ef, ip signaling DSCP = af31

Please rate helpful posts.

Dave

[thisisshanky · Accepted solution]

David,

Not sure if latest IOSes have changed the defaults from af31 to cs3. If not, you will need the following.

*** for mgcp gateways***

mgcp ip qos dscp signalling cs3

*** for h323 gateways****

dial-peer voice 3 voip

ip qos dscp signalling cs3.

[dgahm]

Sankar,

My approach to the signalling change has been to set my class maps to match on either CS3 or AF31. Probably a six of one, half a dozen of the other proposition.

Dave

[thisisshanky]

Dave,

You are right. As long as your switches and routers are programmed to accept cs3 or af31 it shouldnt matter. Another approach would be to keep it all consistent across the board.

[reidg]

Dave / Sankar, thanks both for the replies; answers my question. I do have a follow on however, do you bother applying any qos control methods to the fastethernet interface of the router, or because 99% of the traffic will be either signalling or media, don't bother. Also is there any counters in place to indicate the quantity of packets marked.

thanks

Grant

[thisisshanky]

Typically you dont need to, unless you want to remark the packet tags to something else (say cs3 to af31) as most MPLS or other types of wan circuit providers use different tags for qos in their cloud. If using a packet remarking policy map on the fastE, you will be able to see the counters using show policy-map interface fa0/0 command.

HTH

Sankar

PS: please remember to rate posts!