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New Member

QoS for VOIP

Hello,

I am configuring Qos for voip, but it isn't over a wan link its through the internet. I am wondering if this will still work. I basically made policy maps for the voip ports (UDP 5566 - 5568) needed and set them as the output map for each internet interface. Wouldn't I also need to do some kind of input policy to ensure that each end can receive the voice traffic? Is that how the "service-policy input" command is used? Here is what I did thus far:

class-map match-all voice

match access-group 150

!

!

policy-map VOICE-POLICY

class voice

priority 768

class-map match-all voice

match access-group 150

interface Multilink1

no ip address

ppp multilink

ppp multilink group 1

service-policy output VOICE-POLICY

access-list 150 permit udp any any range 5004 5005

access-list 150 permit udp any any range 5566 5568

access-list 150 permit tcp any any eq 5566

I know I have to do something else for the mlppp to be reliable, but I have instructions for that on cisco's site. I am just curious if anybody has done this over the internet as opposed to a wan link.

thank you for the help.

1 ACCEPTED SOLUTION

Accepted Solutions
Purple

Re: QoS for VOIP

Hi,

Your config is fine and will priorituse vouce traffic out of your link. There really isn't much you can do for incoming traffic since that is dictated by how your ISP schedules traffic out to you.

You should note since there isn't any QoS on the Internet, you are likely to run into latency/jitter issues.

Hope that helps - pls rate the post if it does.

Paresh

5 REPLIES
Purple

Re: QoS for VOIP

Hi,

Your config is fine and will priorituse vouce traffic out of your link. There really isn't much you can do for incoming traffic since that is dictated by how your ISP schedules traffic out to you.

You should note since there isn't any QoS on the Internet, you are likely to run into latency/jitter issues.

Hope that helps - pls rate the post if it does.

Paresh

New Member

Re: QoS for VOIP

Thanks, that's what I thought.

New Member

Re: QoS for VOIP

One more question:

Per my config above, does this limit all my other traffic to 768 less than the total? What I mean is, its a T1, so is all my normal data traffic limited to 768 or does the qos only kick in when voice traffic is present?

thank you

Bronze

Re: QoS for VOIP

If I am not wrong, the QoS only kick-in during congestion.

If there is no congestion, all traffic treat same.

Thanks

Ken

Re: QoS for VOIP

Try "auto qos voip" -jason

Depends if the ISP passes DSCP/Precedece. I imagine they strip it. A sniffer trace on the receiving side would show the DSCP values and whether they get dropped along the way..

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