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DSCP Markins

Hi,

I have been asked to configure a couple of routers for an MPLS link, part of the bandwidth will be allocated for voice traffic.

The interface is a multilink at either end and therefore the telco's guidelines are to user 'priority percent' for Premium, Enhanced and Standard traffic.

Assuming that the split between these types is 50% 25% 25%, do I take it that the router will use the bandwidth statement configured under the actual interface (Serial / Multilink etc) to then calculate what traffic type receives what bandwidth.

Additionally, I assume that the DSCP figures refer to the actual bandwidth for the traffic class. So assuming I have a 2Mb circuit and voice has 1Mb, I need to base my DSCP min and max thresholds based on the 1Mb that voice has.

Hope that makes sense.

TIA for any help.

Regards

Darren

Reply to
Darren Green
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I'm in the same boat, but I have a few sites under my belt so far. In regards to your question the bandwidth statement in the int config mode only applies to the routing protocol your using and if you aren't using a routing protocol then you don't need to use that command.

Considering the three service levels you're being provided with I can only assume that the Premium class will be nothing but voip packets. Most voip systems flag their voip packets as EF. Assuming that you can easily create a class map to identify traffic for the Premium class by the DSCP value EF. However, you will want to ensure that only particular hosts are allowed to use the premium class. To fulfill that requirement you can create an access list permitting the voip systems.

As for the other two service levels I can only guess that the middle tier is likely for your critical client-server applications and the bottom tier for internet traffic like email, ftp, etc. As for identifying that traffic you will probably use access lists or DSCP values of the Assured Forwarding variety (AF).

Here is a link to Cisco QoS documentation.

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Reply to
jdsal

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Thanks for the reply and for clearing up confusion with the bandwidth command.

You were correct, the voice is Premium and I set it to EF and used a Class Map / Access list to identity the VoIP traffic. The other traffic is for various AF levels directed toward Critical & Non-Critical Apps.

The config will use 2 x VoIP boxes connected to their LAN, so my access-list is set to capture voice between these 2 x gateways. From their it routes to their PBX's at either side.

I'll read through the Cisco QoS article today.

Kind regards

Darren

Reply to
Darren Green

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