IP Networking no 2-way audio

[Sobomax]

Hi,
We have a problem with IP trunk between 2 3300 - CXII and MXe III.
There is dead silent when you call from one site to another using IP trunk.
What's the problem??

 

[LoopyLou]

Your network.

The single biggest problem with communications is the illusion that it has taken place.

 

[kwbMitel]

The more details you provide, the better the answers.

The most likely reason is that you are not providing proper gateway information to the IP phones.

I am assuming that you are able to ring the phone but that when the call is answered the line is dead.

When the call is ringing, the controller is directing all of the signalling traffic. When the call is answered, the active call becomes peer-peer directly between the sets. If the sets do not have proper gateways, they cannot talk.

**********************************************
What's most important is that you realise ... There is no spoon.

 

[Sobomax]

Have 2 sites - Site A and Site B
Between the sites there is a VPN running on routers under FreeBSD. Any traffic between the sites is allowed.
IP settings for Site A: 192.168.0.0/24
3300: 192.168.0.2
g/w: 192.168.0.1
DHCP scope: 192.168.0.20-192.168.0.254

IP settings for Site B: 192.168.2.0/24
3300: 192.168.2.2
g/w: 192.168.2.1
DHCP scope: 192.168.2.20-192.168.2.254

What we found is that we need to assign lower MTU on the controller, becouse there are some restrictions about this:

VC1iskra ~]# ping -s 1472 192.168.0.2
PING 192.168.0.2 (192.168.0.2): 1472 data bytes
1480 bytes from 192.168.0.2: icmp_seq=0 ttl=63 time=9.438 ms
1480 bytes from 192.168.0.2: icmp_seq=1 ttl=63 time=9.304 ms
^C
--- 192.168.0.2 ping statistics ---
2 packets transmitted, 2 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 9.304/9.371/9.438/0.067 ms
VC1iskra ~]# ping -s 1473 192.168.0.2
PING 192.168.0.2 (192.168.0.2): 1473 data bytes
^C
--- 192.168.0.2 ping statistics ---
2 packets transmitted, 0 packets received, 100.0% packet loss

How can I do this. I only khow about DHCP option 26. Are there any other ways to change MTU on the controller?

 

[IrwinMFletcher]

And what makes you think it an MTU issue?

 

[Sobomax]

Packets with MTU greater than 1472 was dropped....
Or I'm not right?

 

[IrwinMFletcher]

In order for you to be right, you'd be assuming that MCD sends messages over the MTU limit.

As kwb asked, do the phones ring? If so, then the signaling is fine, it's the streaming, so it could be vlan or firewall issues on the rtp ports.

Describe what works, and what doesn't. The more information the better.

 

[Sobomax]

The phones rings and as you mentioned the signaling is ok.
But when I pick up the phone there is a dead silent as kwbMitel wrote.
I checked the phone setting through the IP Telephones-All form and they are correct.
All IP settings on the controllers are seemed ok. All IP addresses, g/w address are also seemed ok.

 

[tomcotton]

Do you have an IPS or any other Secuirty appliance running on your network?? The signalling uses pretty standard ports, although the voice doesn't so could get blocked. This happens a lot with Teleworker/MBG

 

[IrwinMFletcher]

As the first reply suggested, it's your network. Worst case, streaming uses 216 byte packets, well under the mtu limit.

What you need to do is start to analyze your network. Check your routers/firewalls and make sure that they have the necessary UDP ports open. If you think you have, then start sniffing the traffic from the phone on one side and follow it's path...

 

[bobcheese]

Are your IP sets using the same DG as the controllers? Try calling from an analogue port on both systems this will force the voice packets via the controller at each end rather than set to set. Controller sets up the call and then voice stream is peer to peer so sounds to me like the phones gateway does not have a route to the other network.Check your DHCP options