One Way Communication 1

[frk007]

Hi
I am receiving one way audio from my call manager 4.3 to a Cisco IP Phone. The Cisco IP phone is located at a remote site. Can anyone please help

thanks

 

[mtashiro]

This is caused by a routing issue. The IP Phone does not know how to get back to the other site.

 

[pmoorey]

This can be caused by many issues, however it is unlikely to be a routing issue as for the phone to register (which it must have to in order for one way voice to be detected) it would have to have correct routes.

I would investigate whether the phone is being NAT'd, and then check firewalls for blocked traffic, and that protocol fixups are enabled if required.

Hope this helps.



Peter
CCNA, Cisco Qualified Specialist

 

[mtashiro]

What I am saying is that the routes to CM are fine but the routes to the other phone may not be.

In other words:

Phone A to Callmanager - Good
Phone B to CallManager - Good
Phone A to Phone B - Good
Phone B to Phone A - Bad

While there isn't enough info from the original thread to determine what the network looks like.

I also agree with you that firewalls could be an issue as well, again not enough info in the thread.

 

[mtashiro]

BTW: A simple test of a routing issue is to source ping from Phone B subnet to Phone A subnet and visa versa.

 

[Wavesg]

I agree with mtashiro..try pinging

Stay cool; it’s not over yet!

 

[Wavesg]

Also before you can troubleshoot any firewall issues, you have to make sure the routing is in place. Can't troubleshoot access if you're not sure if the packet is being routed.

Stay cool; it’s not over yet!

 

[frk007]

Sorry about not enough info.

There are three sites at my workplace

How is the Site connected
Site A is connected to Site C
Site A is connected to Site B

in order for Site B to communicate with Site C it must pass through Site A

Site A has a call manager publisher

Site B has a call manager publisher

These two call manager are not on the same cluster.

I have established a connection with Site A and Site B with an inter-cluster trunk (non-gatekeeper controller). I was having one way audio communication between Site A and Site B until I check the MTP required then I receive two way audio communication.

At Site C one IP Phone is connected for communication to Site A and Site B.

The IP phone is register to the Site A call manager and one way audio communication is being established. Site A and hear Site C but Site C cannot hear Site A.

However when Site B calls Site C I am getting a two way communication.

 

[mtashiro]

Do the Site C phones and Site A phones on the same Cluster?

 

[frk007]

Yes there are on the same cluster

 

[mtashiro]

So as I understand it:

Site A phones - Site A cluster
Site C phones - Site A cluster
Site B phones - Site B cluster

Calls from A to B work
Calls from B to C work
Calls from A to C don't work (Site A can hear Site C but site C can't hear site A)

Sites B and C connect to site A in a hub and spoke configuration.

What are the IP subnets for the 3 sites?

 

[frk007]

Site A is 10.5.24.X

Site B is 10.10.24.X

Site C is 90.7.255.X

 

[mtashiro]

What is the IP Subnet of the two CallManager Clusters?

Thanks.

 

[JacobNunley]

I would check what interface you have your media and control source bind to.

exmaple.

mgcp bind control source-interface GigabitEthernet0/0.30
mgcp bind media source-interface GigabitEthernet0/0.30

 

[mtashiro]

Don't think that is it since these are IP phone to IP phone calls. Not PST calls through the gateway.

 

[cgangadeen]

I think this might be a routing issue. We also got a similar problem with almost the same set up. However it was a single cluster and three sites and we finally managed to resolve it. It was a routing issue.

 

[mtashiro]

I am pretty confident this is a routing issue. Just waiting for the IP subnets of the two clusters.

 

[mtashiro]

Try source pinging as follows and give results:

Site C phone subnet to CallManager Cluster A - This should work

Site C phone subnet to Site B phone subnet - This should work

Site A phone Subnet to Site C phone subnet - Guessing this does not work.

Assuming these results are true, fix the routing.

 

[frk007]

IP subnets for Cluster at Site A is 10.5.24.X and Site B is 172.17.0.X


Site C phone subnet to CallManager Cluster A - Yes this works

Site C phone subnet to Site B phone subnet - No Site B and C does not have routing between each other. But communicate with two way communications

Site A phone Subnet to Site C phone subnet - Yes this works

 

[VoIPFANATIC]

Make sure tcp port 2000 for Skinny (sccp)protocol is passed bi-directional between the various subnets. and udp RTP uses ports 16384-32767. if the end device is a softphone.

hope this helps.