One-way audio issue

[D@1984]

I'm having one- way audio issues on both inbound/outbound calls on my phone ( I can hear caller but they cant hear me). I swapped my phone with a working phone and experienced the same issue, so I'm guessing something should be wrong with the switch port rather than phone setting as even the replaced phone didn't work when I plugged in to my port.

I compared the switch port config with other ports and it has the same config. any idea what the issue could be?

Many thanks

[jonathan.salter]

Typically a firewall issue or a network routing issue.

Did this just start happening? Were there any changes made in the environment?

[D@1984]

this is the only phone in the same network that doesnt work. so port config and routing for this phone are the same as others.

[@Syed]

Problem with internal or PSTN calls?
Internal:
Verify end to end IP routing among network segments, also make sure RTP ports are opened if there is firewall along the way.
PSTN:
Verify IP phones' network segments have reachability to voice gateway and RTP ports.

[anamika]

Hi Syed, how do you verify the route path for RTP stream from one ip phone to other ip phone and also if ip phone has reachability to the voice gateway.

[Dennis Mink]

I would use wireshark to do this, 

so these types of issues you would also need to look at the SIP SDP to see what the IP addresses are in the RTP stream.

but again, wireshark can confirm if you are actually receiving RTP (used in conjucntion with Jabber softphone)