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User on 7940 "cutting out"

I have a CME deployment with 15 phones and a 2821 router running CME 3.2. All phones are here in the office except for two - one about 300 miles away and one about 2800 miles away.

The user on the phone 300 miles away is experiencing bad call quality, what called parties describe as "cutting out" randomly. I had a conversation with her and it sounded to me like it would sound if you were talking on a device that was only half-duplex. I could hear her fine unless I made a noise on my end, which would cause her audio to cut. She is on a 7940 that is connected to the office via an IPSEC VPN link via a 1.5MB/1MB DSL line.

The user who is 2800 miles away on a cable modem with the same VPN setup sounds great, like she is in the next room.

We have had no problems like this with any of the other phones.

Anyone know what could be causing the calls to sound like they are half-duplex? I checked the network stats and everything looked pretty good, phone port is 100/fdx, no drops, some jitter.

Thanks,

Chris

4 REPLIES
New Member

Re: User on 7940 "cutting out"

This is a followup --

I did some research last night on common voice quality problems and this particular problem can be best described as "choppy" or "clipped" voice. I had a feeling that VAD could have been causing the cutouts, but it doesn't make sense to me that I can talk to someone in the office and both of us can be making and hearing sound at the same time, but when I talk to this remote user, even background noise on my end cuts her out.

Anyone have any suggestions as to how to correct this?

New Member

Re: User on 7940 "cutting out"

Do you have any QOS set up? I have seen this with no QOS the distance from you has little to do with it. What is your round trip delay to the distant router and is the interface showing a lot of dropped packets.

New Member

Re: User on 7940 "cutting out"

No, we are not running QOS yet. That was one of the things I had been planning to do before we rolled out the phone system, but things go from "test" to "production" so quickly. :)

Next goal is to get QOS set up on the WAN links at least. I don't notice a lot of dropped packets on the tunnel, but the phone reports a lot of jitter.

New Member

Re: User on 7940 "cutting out"

i agree with previous post. first check ping time from central office to dsl vpn. then test from central location to cable vpn. sounds like a poor dsl connection to me. maybe too far from the local co for good dsl. also, verify the vpn settings are the same for both the cable and dsl connections.

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