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Community Member


Hi all,

I am new in QoS and trying to apply it in two of my voice links. I have

a voice circuit (1xE1) between our office and HQ in USA and another

voice circuit (3xE1) with another branch. I have only voice and

signaling traffic on the USA circuit and the encapsulation is HDLC. For

the brach office the 3xE1 links are bonded by MLPPP and I have voice,

signaling and data. I am using a thrid party device to compress the

voice (G.729A) and signaling (SIGTRAN) and that device can put ToS bit

in voice and signal packet. Now here is what I want to do..

1. For USA circuit I want to give higher priority to signaling by

putting ToS bit in my compression device. Can the router detect that?

Do I have to do any additional QoS configuration in the router?

2. For Brach office I want to have Signaling higher proirity, next

voice and default priority to data. Same like USA circuit, I cam put

ToS bit for signaling and Voice but as data is not passing through the

compression device I cannot put ToS there.

It would be very nuch helpfull, if anyone can send some sample

configuration or links to solve my problem.

Thanks in advance.


Cisco Employee

Re: SIGTRAN and Qos

This may work OK mand the routers will rread the TOS bit and act accordingly, however the drawbacks are that this mechanism cannot control what interfaces queues will be used. Take a look at this link:

This would be the correct way to do it and change the HDLC link to either MLPPP or frame relay.

Hope this helps.


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