need QoS example config

[eortizrovira]

I have router 2951 ISR, and I need to create a QoS policy for the VOIP phones, the router will be using 2 T1 on a multilink and it will share all the company internet/intranet traffic with the voip traffic.

Thanks

[Terry Cheema]

See below an example, creating one class for VoIP Audio, you can create more classes and call it from the policy map and assign the bandwidth % accordingly.

Apply the service policy to your Multilink interface and assign the percentages instead of bandwidths. So this was even when one of your link is not available your QoS will be still relevant.

class-map match-all VOICE
match ip dscp ef

policy-map VOICE
class VOICE
priority percent X
class class-default
fair-queue
random-detect dscp-based
 

interface Multilink XX
service-policy output VOICE

Refer to this as well if that helps although an old document: http://www.cisco.com/c/en/us/support/docs/voice/voice-quality/7111-voip-mlppp.html

-Terry

Please rate all helpful posts and mark the thread as answered if you have no other queries.

[Dennis Mink]

Please note that with the example above (thanks Terry), you will need to make sure that you set your "voice related" packets to have ef set before they hit the 2951, or at least verify that this is happening.

otherwise you voice traffic might un-intentionally end up in another traffic class based on an incorrect DSCP value.

[Terry Cheema]

Ok - Since Dennis has raised this, the classification is just an example, classification can be done using ACLs or various other mechanisms, you will need to set up trust or conditional trust on access layer to receive the markings.

But as said in the above post, Please note you will need a lot more classes - this is exemplary audio class. You will need to classify signalling, your critical data etc.

Above is a pointer on how to do this on a Multilink.

-Terry