Jabber & Anyconnect - calls connect but no voice

[karl.jericho]

Hi everyone,

We have a customer running CUCM 8.6 and Presence 8.6, and an ASA with Anyconnect enabled.

They can connect to the VPN and connect to the Jabber client, but when making a call (whether external or internal) it connects, but without any voice/audio. We thought from a previous job with another customer it was an issue of routing, but the 10.0.0.0/8 network is part of the secured routes (phones on 10.5.0.0/16 and servers on 172.26.2.0/24), and also no ACLs are configured for the VPN profile.

I'm not particuarly fluent in Jabber, although know my way around the ASA and CUCM. What can anyone suggest to show or debug when making a call to determine the issue?

Thanks in advance,

Karl.

[karl.jericho]

Hi everyone,

Ok, we've worked this one out. It was NAT after all.

Depending on the between which devices you were making a call, determined between which devices RTP packets were flowing.

Between VPN client to VPN client

• RTP packets directly. Call successful.

Between VPN client to Jabber on internet desktop

• RTP packets directly. Calls unsuccessful. Added no NAT to internal host to VPN clients. Calls successful.

Between VPN client and desktop phone

• RTP packets between MTP and VPN client. Calls unsuccessful. Added no NAT to MTP address to VPN client. Calls successful.

A tricky find but we got there! As a network engineer, before you go to sleep at night you need to ask yourself "Did I remember to turn the NAT off?"

Karl.