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New Member

QoS for Voice traffic

Hi,

Can I know the purpose using the following configuration? Will it help to prioritze voice traffic?

class−map match−all Call−Control

match access−group 101

!

class−map match−all RTP

match ip rtp 16384 16383

!

access−list 101 permit tcp host 10.120.16.112 any eq 1720

!

!

!

policy−map OutboundPolicy

class RTP

set CoS 5

!

!

class Call−Control

set CoS 3

set ip precedence 3

!

!

!

class class−default

set CoS 0

!

!

3 REPLIES

Re: QoS for Voice traffic

hi

From the configs posted here you are just classifying the traffic based on the RTP port numbers which is placed under RTP class map and also the control traffic under call-control class map.

Under the policy map you are again marking those classified traffic with COS 5 and COS3,IP Prec 3.

Rest all your traffic is being put under default class and marked with COS 0,i feel this is not the config taken out from the edge may be from one of your LAN switches..

regds

Purple

Re: QoS for Voice traffic

Hi,

The policy map you have posted is part of setup that can be used to prioritise voice traffic.

While the policy is called Outboundpolicy, it would be more useful at the ingress point of a switch. However, it can be used on the egress interface of a switch. The policy does the following:

- recognises RTP (voice payload) traffic and marks it with a CoS of 5. It does not mark the IP precedence value of the packet, however. The following statement could be added to do so: set ip precedence 5

- recognises voice signaling traffic and marks it with a Cos of 3 and an ip precedence of 3. In fact, it's only matching on H.323 which uses tcp port 1720

- everything else is marked with a CoS of 0. Once again, IP precedence should also be marked to 0 here.

Hope that helps - pls rate the post if it does.

Paresh

New Member

Re: QoS for Voice traffic

And just to add to the previous comments, the policy will mark your traffic at the edge of your network and will be applied as an input policy map to your interfrace. Going out towards your core, you need to prioritise the traffic using another policy map which will be applied in the oubound direction, using the priority command for your voice traffic.

Have a look at the following:

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fqos_c/fqcprt8/qcfmcli2.htm

http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/qos_r/qos_o1g.htm#wp1076758

Rgds

E.

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