Cannot hear on branch office calls

[Anthony O'Reilly]

Hi,

Our DR Site which is connected to our HQ and we have 100 Cisco IP 7941 phones. If a call coming into head office and ring on the phones in our DR Site, we can hear the customer and they can hear us. However, when a call comes into the DR Site from a branch office, the customer can hear us but we cannot hear them.

Any ideas anyone?

Thanks

Anthony.

[Giuseppe Larosa]

Hello Anthony,

it takes some time because there is the SP network in the middle.

Another aspect is that also the SP may have his route filters.

If you still don't see the routing updates you may need to talk with service provider people.

It is uncommon that a service provider filters routing updates but they can implement some control on the number of routes received to protect themself from someone sending by error two many routes.

Hope to help

Giuseppe

[Anthony O'Reilly]

Hi Giuseppe,

I did a soft reset on BGP and the route is now in the sh ip bgp on the branch office routers. I hope to go to our DR Site today and make a test call. I will let you know how I get on.

Thanks a millon for your help

Anthony.

[Anthony O'Reilly]

Hi Giuseppe,

I am in the DR Site now and I can hear the local branch staff and they can hear me.

Thanks a million for your help.

Really appreciate it

Anthony.

[Nicholas Matthews]

Hi Anthony,

What can be extremely helpful in troubleshooting the one-way voice issues is knowing what IP addresses you're dealing with. To find out what IP address your IP phone is sending RTP to, go the the webpage of the phone when it's on the call, and go to stream statistics. This will tell you what IP you're connected to, as well as if it's receiving packets or not. It's possible to get one way audio with two-way reachability if you're getting blank packets.

From there, you can troubleshoot reachability from the phone's default gateway.

It's possible you have MTP/Transcoding for these calls and the RTP stream will not be IP phone to IP phone. Or as previously mentioned, you could have a asymmetric routing through a firewall or ACLs.

If the one-way audio happens only on PSTN calls, you can use 'show call active voice brief' to help determine the problem. This command will list the IP address and RX packets for a certain connection on the gateway.

hth,

nick

[Anthony O'Reilly]

Hi Nick,

Thanks you for your input