QOS over a WAN link

[dvanzee]

We are setting up faxing over our PTP link and someone has mentioned that we will need to give priority to this fax traffic, Can anyone tell me how I can accomplish this?

[m.matteson]

check out this post from yesterday.

http://forum.cisco.com/eforum/servlet/NetProf?page=netprof&forum=IP%20Communications%20and%20Video&topic=IP%20Telephony&CommCmd=MB%3Fcmd%3Ddisplay_location%26location%3D.1dda5c40

[mheusinger]

Hello,

what you would need is priority queueing for your fax traffic. One way of accomplishing it would look like this:

ip cef

class-map match-all FAXtraffic

match protocol rtp

policy-map LLQ

class FAXtraffic

priority percent 20

class class-default

fair-queue

random-detect

interface Serial0

ip address ...

bandwidth 1024

service-policy output LLQ

You need to adjust your bandwidth statements and percentage values to suit your requirements. The "priority" command will ensure lowest delay, but be aware that a policer comes with it and you have to make sure to configure enough resources to support your FAX traffic.

The class-map could also be set up with an access-list. Just make sure your fax traffic is properly described.

For a full description of available commands and configuration examples have a look at "Cisco IOS Quality of Service Solutions Configuration Guide"

http://www.cisco.com/en/US/products/ps6350/products_configuration_guide_book09186a0080435d50.html

and especially the parts 1 and 2. In general AutoQoS might be worth reading, because it simplifies the configuration.

Hope this helps! Please rate all posts.

Regards, Martin