Dropped Calls and One-way Audio

[mkbrick]

Will a bad system tray cause dropped calls and one-way audio on a BCM450? My local vendor is about to switch ours out as we are having huge issues with drops and no outbound audio. Thanks!

 

[JustAGlitch]

What kind of trunking do you have in the 450? What kind of sets? What version is the 450?

If It's Not Broken...Don't Fix It!

Stephen Webb

 

[mkbrick]

SIP trunking. Nortel T7316E. BCM 450 Version 5.0

Leaning toward the Cisco 2821 router. What do you think?

 

[QueBall780]

At some level a bad system board could do lots of strange things but I would not expect a problem that is so specific. I would see more likely problems being corrupt hard drive, random rebooting, problems with digital sets or analog lines because of bad voltages. General odd behaviour, not really specific odd behaviour.

With one way voice path it's usually some kind of network issue. A security setting that blocks the connection or some settings that cause the SIP packets to have incorrect IP address so the device on the other end sends replies that go to the wrong IP.

Suggest you simplify your connections if possible. Make sure you can reach the IP address of both end point devices that are trying to communicate. If you can test with your two devices plugged in with a boring old dumb network switch between them and it works then you have some network level blocking at some point.

In my case when we have that kind of problem it usually happens with a user who works from home via a VPN connection. Only when they try to call someone in a branch and the VPN tunnel that allows traffic from their home to the branch location has dropped. So the call goes through, but they cannot talk to each other because there is no direct path from one to the other. There is a path to the central office for both users but not a direct network path from one to the other when that VPN tunnel is down.

With the VPN hardware I have there is some kind of a glitch where the configuration looks correct but the order the VPN tunnels get created seems to make a difference. If the VPN for the central location is setup prior to the branch location it takes priority and the tunnel to the branch never gets attempted. Supposedly they fixed the bug in a later version of the software, but the equipment at one site is older and cannot run the latest software so we need to replace it some day.

 

[mkbrick]

Thanks. Some other systems are as follows:

Calls from some carriers deliver (we can see them on abandoned call reports) but don't even ring.
Calls ring twice and drop.
Calls deliver and then our outbound audio drops during the conversation. The inbound audio continues.

Any ideas?

 

[telcodog]

How are your SIP trunks being delivered by your provider? Are they just coming in via the internet through your DSL or does your provider provide them via MPLS or through SBCs at each end etc?

What you're describing are symptoms of an inadequate data connection. Could be something on the BCM but you would likely see all kinds of errors in the error log if the system were causing those kinds of problems. Have you seen anything in there?

 

[mkbrick]

Nothing in the error logs. Calls are delivered via MPLS. Many of the dropped calls are delivering the ANI packet as we see the call on abandoned reports. The rest of the packets are not there though.

 

[telcodog]

You didn't say who your voip carrier is but some of them require changes from the defaults in the BCM. Check your packetization time. The BCM default is 30msec but some carriers need it to be 20. If you have IP sets. make sure you change it on them too. Also check the payload size, it should be set to 120.