VoIP One way speech problem

[teleplop]

Here's a good one. I have a BCM 400 with 20 T7316E phones. 20 i2002 connected via a T-1 network conection. (Works fine) this system ties to a BCM 50 via VOIP trunks. (Also works fine) Here is the problem. I have 4 i2002 sets at a remote site that are connecting to my 400 via business class DSL. The phones are connected to the 400 and you can call the digital sets with no problem however, they get one way speech to the IP sets on the 400 and no speech via the VOIP trunks to the 50. The phones ring and the calleer id comes through but no Speech. Ports are wide open on all routers....any ideas? Anyone?

Teleplop

 

[biv343]

Is this a VPN connection? It sounds like something is being NATed in the DSL world that is causing the one way speech.

If it's a hardware based VPN, there shouldn't be any issues.

 

[teleplop]

It is a VPN connection through a cisco router. NAT is not turned on.

Teleplop

 

[teleplop]

To be exact, it is a VPN tunnel. No NAT.

Teleplop

 

[biv343]

Might be a stupid question, but what network/subnet are the IP phones on at the remote site (the 4 i2002's)? From that network, are you able to ping any of the phones that are on the LAN with the BCM 400? Is the BCM 400's default gateway the IP of the VPN box?

It still sounds like something in the VPN isn't quite right. What info does the BCM monitor give you in the RTP stats when making a call that has no voice path?

 

[teleplop]

biv343...you raise some very good questions. The subnet at the remote site is 255.255.255.0 I didn't try to ping the phones on the 400 so I will try that. Now on the last question I am really puzzled. I have the BCM 400 default gateway set to the the DG of that local network...Now having said that, can I set the DG on the BCM to 2 fifferent IP addresses?

Teleplop

 

[biv343]

Nope, but you can build a static route to the remote network pointing to the IP of the VPN concentrator as it's next hop.

 

[teleplop]

Do I do that on the BCM or the one of the routers?

Teleplop

 

[biv343]

On the BCM - under services, IP routing, static routes.

 

[teleplop]

Thanks I will gice that a shot.

Teleplop

 

[MagnaRGP]

If the calls ring fine, then there is no problem with BCM to set signalling.

Sounds to me like a routing issue at the sites. You indicated that the IP sets at the remote cannot speak to the IP sets at the main. This says to me that they can only see the BCM and not the other IP's. Remember that the BCM is only in use (set to set) during call setup. After the call establishes, the IP sets talk directly to each other, so the audio stream is getting misdirected on one side.

Is it a Branch Office VPN tunnel or a User tunnel. Also check that your VPN routers have Branch to Branch traffic allowed.