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VoIP with ATA 186 over Frame Relay

For anyone reading this, I have searched high and low and I am really interested if anyone has any thoughts. We have many different sites and are trying to impliment VoIP at a few of these sites. We are currently running Cisco Call Manager 3.2 currently and I have purchased an ata 186 device to connect our remote site.

At our main site we have a 3640 configured for 2 remote locations with voice configured and about 156 other locations all using frame relay. At the site I am trying to connect the ATA I have a 1720 router with a 56k FR link, with 56k CIR. I am also testing this at another site with 56k FR and 8k CIR. I followed the LLQ procedures and now have that working.

After I got that working I set my voice policy to priority 45 as it says in those procedures and watch packets on the "Show frame-relay fragment" command I think it is, and notice when im on the phone the voice is choppy and it keeps adding packets to the "Dropped" portion of that policy.

So what I have assumed from this is that my LLQ policy is fine (and the voice is much better then when I didn't have the policy) but I don't think I am really using G729a that I want the ATA to be using. So I have looked around and the only thing I can think of is setting up a dial-peer on our main 3640 to use codec g729a for that remote location exclusively. So two questions, first am I forgetting anything? is there another reason this would be dropping packets off of the QoS Policy? Second when I set up the dial peer am I setting it up as VoFR or VoIP cause the box has an IP address to it and/or is that what is happening and/or is that the only way to get it to work and be sure its really using G729a. Any advice would be greatly appreciated.




Re: VoIP with ATA 186 over Frame Relay

Frank, its important to know what codec you are using and how many concurrent calls are going through at a time. even if youre using g729 you are using 24 K per clal and if you have two calls then that is oversubscribing your priority map.

A good way to check is to do a show policy map and see where the drops are occuring. If your voice queu is dropping packets youre in trouble.

Community Member

Re: VoIP with ATA 186 over Frame Relay

I looked at that policy map and it is dropping packets in the voice queue. We only would have 1 concurrent call at a time. I would figure a 56k/56k line should be able to hold that one call fine and quality should be good, but it still dropping so I suspect its not really using G729a its trying to use something else and thats why its dropping packets.

Any ideas?

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