SIP - rings with no voice

[joe.marcelo9]

Hi 2 All

We got an issue and hope to get some help.

Our PSTN lines are terminated on Nortel System, recently we have installed CME on 3800 series Router.

So far managed to integrate Nortel with cisco and now we can call/receive between nortel and cisco. H323 is used between Nortel and cisco

Calling outside our company with sip endpoints registered on cisco is working.

Calls initiated outside our organization to extensions registered on cisco I can hear ring but no voice.

All codecs are same G711 a / G711u / G728AB but no voice.

For test purpose we installed xlite and it works for local extension calling, and calling to anyone outside our organization.

recceiving calls from outside our organization on endpoints terminated on Cisco is not working, it rings with no voice.

If Someone calls from outside our organization to endpoints terminated on nortel then its working.

Any help

[P3Myee]

Hi, Guy

You mentioned that ringing but no voice, so the signaling from outside sip endpoint to CME and internal extension to CME is ok. No voice i suggest you need to check the connectivity directly between the outside sip endpoint and internal extension. any useful port denied? layer 3 connectivity?

Hope useful to you!

[joe.marcelo9]

hi

I dont think its a Layer3 connectivity issue. No ports denied.

any more input.

[joe.marcelo9]

Any Help guyz

[CHRIS CHARLEBOIS]

If the calls complete but there is no audio, or one-way audio, I usually check for something preventing the RTP stream.  This could be a layer 3 problem or an ACL, as previously mentioned.  But it could also be Network Address Translation, or even just a deep-packet and/or stateful-inspection firewall.  Even if the firewall is configured to allow RTP traffic through, some (particularly older firewalls) just don't reassemble the RTP packet right.

Let's clarify what is and is not working.  You have CME with SIP endpoints, and internally calling between all SIP endpoints is fine.  You have a Nortel PBX, connected to the PSTN.  Does the Nortel have any endpoints?  Can the SIP endpoint on CME dial and be dialed by the Nortel endpoints?  The Nortel and the CME VG have H.323 gateway service with dial-peers, correct?  From your description,  it sounds like the SIP endpoints can dial the PSTN and they received audio both ways.  However, if the PSTN dials a SIP end point, the call connects, but there is no audio in either direction.  That makes me think it's an inbound dial-peer matching issue.  Do you know what dial-peer is matching the inbound call leg for calls comeing from the PSTN to the SIP phones?  You also mentioned remote SIP endpoints are working?  Where are this endpoints and how are they connecting to the CME and the Nortel?

[joe.marcelo9]

Thanks for replying.

Let me put allover again.

PSTN lines are terminated on nortel CS1000

We recently installed CME on a router to support 25 users.

Inorder for enpoints terminated on Cisco CME to communicate with Nortel we integrated both systems using H323.

calls from endpoints terminated on nortel to endpoints terminated on cisco is working  ( Internal extension to extension calling )

calls from endpoints terminated on cisco to endpoints terminated on nortel is working  ( Internal extension to extension calling )

calls from endpoints terminated on nortel to outside company is working

calls from endpoints terminated on cisco to outside company is working  ( SIP endpoints & cisco phone endpoints )

PSTN calls for endpoints terminated on nortel is working.

PSTN calls for endpoints terminated on cisco CME only sip is not working  ( its rings with no voice )

PSTN cals for endpoints terminated on cisco CME with cisco endpoints is working ( cisco phones )

I tested sip endpoints Snom 870 / Xlite / Linksys / D-link all have same issue ( ring with no voice )

If more input is needed then I can add

thanks

Joe