Cisco One Way Audio

[dougp23]

This has happened 4 or 5 times in 2 years, but twice in the last 3 months.

Someone calls in and they get the automated greeting. The greeting accepts no input (i.e. Press 1 for this, 2 for that, any key you press, the greeting continues. Entering an extension is also ignored).

I can call DID lines, but the person on the other end will not hear me, but I can hear them fine. Even internal extension to extension calls will have this issue when it comes up.

So far, the solution is to reboot the main 2801 (which has the PRI). I am not sure why this would fix ext to ext calls, but it does. (The 2801 is running a 12.3 version)

My question is why does rebooting fix ext to ext calls? Why does this only happen intermittently like this? The last time we went 6 or 9 months with no issues whatsoever.

Any ideas would be great!

 

[ADB100]

One way audio is usually always a routing issue - i.e. the path from endpoint 'A' to to the endpoint 'B' is correct, however the path from endpoint 'B' to to the endpoint 'A' isn't. I have also seen duplicate IP addresses cause the same issue - i.e. someone spoofs the routers IP address so traffic is sent to the spoofer instead of the router.

When this happens you need to ensure the path in each direction is working - i.e. from a device on the same subnet as one of the endpoints ping the other endpoint and vice versa. If its a duplicate IP address issue then you would also need to check the ARP cache on the last hop devices (i.e. the endpoint and its default gateway).

HTH

Andy

 

[mcwxmcw]

We had a similar issue and it ened up being a firewall issue. Watch you firewall logs during a call and you'll see what ports are being denied.