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New Member

Hosted UC - one way audio


I have a customer with a Hosted UC solution, so we have the UC servers (virtualized CUCM version 8.6 in UCS servers) installed at two locations, using different VLANs and Firewalls between servers and IP Phones. The firewalls between the servers at both sites are allowing all traffic.

My primary server is a Site A, the secondary at Site B. On Site A I also have Unity Connection (version 8.6) and Contact Center (3rd party)

When I shutdown my primary server, all the phones register OK with the secondary server. Calls between ip phones work OK. Inbound calls from PSTN (SIP) to Contact Center and to Unity Connection work well as well. But inbound calls to internal extension, outbound calls or calls from IP Phones to Unity connection have "one way audio".

I want to know what to check "easily" on troubleshooting.

I have some traces from the secondary server, when the primary is down. The signaling of the call is fine, but not the media. What I should check?

Thanks for the responses,

Rafael Paniccia

Cisco Employee

Hosted UC - one way audio

Hi Rafael,

     Lets start simple on this one and follow these steps:

> Let us concentrate on the calls to CUC wich face one way audio, since that call involves less places where things could wrong.

> Failover one of the phones to the SUB and then make a cal to CUC. Collect the detailed CCM traces for this call.

> Upload the traces here and let me know the calling and the called number.

Also, how do we integrate the CUCM to the CUC; SIP or SCCP?

For the above test call:

> Once the call is connected to CUC; please hit the "?" key twice on the IP phone and see if the Sender and Recieve packets are increasing? Test this while leaving a voicemail, not when listening to an IVR or a greeting.

I have a strong feeling this will turn out to be an IP routing issue.



New Member

This problem was related to

This problem was related to firewalls and open ports. Since the the solution is hosted, there are firewalls between the IP Phones and Call Managers, Unity Connection and Contact Centre.

One way to deal with it was to use Media Termination Points (MTP) but that limits the amount of calls that could be answered during a failover scenario to the amount of "MTP ports" available to use.

The other, to open the firewalls and allow them communicate more freely over the firewalls. This was the solution implemented, making it clear the range where the IP Phones are, and allowing their communication to the selected servers.


Rafael Paniccia

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