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Beginner

No audio when external call is transferred (CFwdAll) to external number

Hello,

 We have the following setup:

(IP phones) <- (sccp) -> CUCM <- (SIP) -> CUBE <- (SIP) -> IP Telephony Service Provider

No issues with inbound and outbound calls. Also internal calls can be forwarded to external number and it all works fine.

The problem we are facing is when we set CFwdAll on a Cisco phone to external number, and someone tries to call this Cisco phone from PSTN. In this case the call is connected but there is no audio at all.

We use g.711 codecs everywhere. I am attaching the CUBE config and "debug ccsip messages" for a test call. I can't get "debug voip rtp connections" right now, but when I did a test last night it was showing 4 RTP connections - two sessions from the public CUBE interface to ITSP, and two sessions between the LAN interface and the LAN interface itself.

Your help will be appreciated.

Thanks!

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Rising star

Do you have any firewalls in place between any of the Voice equipment and the ITSP?

Have you tried a packet capture to see if you can see the RTP traffic?