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New Member

QOS over a WAN link

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?

  • WAN Routing and Switching
New Member

Re: QOS over a WAN link


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



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"

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

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