No Audio on VoIP Calls in CUCM 8.6

[jameskuder]

We are attempting place calls internally by dialing the 7 digit extension at any of our remote sites From our HQ.  All cites are registered to Cisco Call Manager v8.6. When you place the call, it goes through and is abled to be answered. You can see that other internal party has answered but you cannot hear them and vise versa. What would cause this

[Jaime Valencia · Accepted solution]

No way audio and one way audio is most commonly related to routing issues.

Press ? twice on the phones you're using and see if you're receiving any packets.

HTH

java

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[jameskuder]

I do not have a ? on my phone. Can you be a bit more specific on the routing issues?

One thing is that we have multiple voice and data vlans at our HQ. They are different from the one at our branches. Meaning, our branch sites use data vlan1 and voice vlan 5. Our HQ site has several data vlans including vlan1 and also several voice vlans which do not include voice vlan 5. If I call from my phone at the HQ which is on voice vlan 195 (19th Floor) to a branch site that has a phone on voice vlan 5. When the call is made, the issue exists. If I change my voice vlan to 5 and try the call again, it works just fine and I can hear them and they can hear me. We are unable to set all phones at our HQ to voice vlan 5 due to the limitation of IP addresses, thus the needs for several.

[acampbell · Accepted solution]

James ,

Java is spot on re oneway/no audio usually being related to an ip routing issue (+5 Java).

You need to check and ensure that there is a layer3 ip routing path between your voice vlans like you quoted 5 & 195.

Make sure that any router/firewalls are not blocking the rtp streams or ip ranges.

For vlan 5 to reach vlan 195 you must be going through a layer 3 device

|---------VLAN 5-----| ROUTER (LAYER3) |---------VLAN 195-----|

The fact that you can set up calls and riging etc only proves that the CUCM can route to the phones for signalling.

The voice to voice vlan routing is a MUST for the rtp audio stream.

Regards,
Alex.
Please rate useful posts.

[jameskuder]

I will have to circle back to our Sr. Network Guy. When I mention the possibility before about the network and vlans, he just said it is not the network and that was that. The routing also applies to voice vlans as well, correct? What about codec issues?

[Jaime Valencia]

Most commonly codec issues would cause the calls to drop as soon as you answer, anyway, just make sure they're using g711

Sent from Cisco Technical Support iPad App

[jameskuder]

Thanks all. We were able to isolate the issue. It was an issue with the branch firewalls. The branch phones/router are in a dmz and could not access access the HQ phones over the WAN.