issue in one way audio on IP phone

[kaito336]

we have strange issue

we got IP telephoney 9971 when i call internal everything is right when I call via SIP the outside phone ring and when he answering I cannot hear him but he can hear me.

when he call me we can hear each other without issues. and I replace it with sccp phone everything is fine.

what is the solution with 9971?

[AbuAkif Riyaz]

Hi

Did you try with other model Cisco SIP Phone for the same testing?

Please try to collect both logs (One way issue/Two Way normal). If it is possible please share.

[kaito336]

Hi all 

Thank You for fast reply

Mr.mohammed actually I don't have access to the router and the other phones we tried are Sccp Phones.

but we have two SIP Phones and the same issue.

Mr.dennis if the problem was ip routing issue or access list it could affect all the phones because all of them from the same subnet , am I right? the problem is sip phones do you think guys if we made upgrade would solve the issue?

[Dennis Mink]

This is typically caused by an access list or routing issue.

does this happen with other phones in the same subnet?  or is it a single phone in the subnet?

see if you can try to ping the iP address of the remote end of the RTP stream, if not make sure you can.

also can you tell us what is in the path of the RTP stream?

[kaito336]

thank you guys for fast reply

Mr.mohammed actually I dont have access to the router to get logs.But if the issue in the router why other phones are working fine? 

the other phones are SCCP Phones and working fine.

there are two SIP phones and the same issue for both

Mr.Dennis if the problem was access list or ip routing it would affect all the phones because they are in the same Subnet,am I right? do you think guys if we made upgrade would it work?

[kaito336]

When debugging rtp it shows for just sip phone:

:rtp_udp_unreachable:Entered: ICMP unreachable for dest(XX.XX.XX.XX),src(XX.XX.XX.XX))

[kaito336]

when debugging rtp it shows this on just sip phone:

:rtp_udp_unreachable:Entered: ICMP unreachable for dest(XX.XX.XX.XX(17091)), src(XX.XX.XX.XX(18833))

[AbuAkif Riyaz · Accepted solution]

Hi

1. Many factors will be there for stopping SIP signalling/media in security point of view. For example if you enable SIP Inspection this kind of misbehavior may happen.

Please refer here for more information https://www.voicehost.co.uk/help/sip-alg-and-why-it-should-be-disabled-your-router

I can suggest you to take first point of troubleshooting as to collect logs from IP Phone when doing the test scenario.

2. Please do the following for collecting Packets from from IP Phone through your PC. https://community.cisco.com/t5/collaboration-voice-and-video/collecting-a-packet-capture-from-a-cisco-ip-phone/ta-p/3119480