atcomsystems.ca/forum Forums TDM Business Telephone Systems NEC Telephones & Systems VOIP across Layer 3 VPN

I have an NEC ASPIRE system that I am trying to get to work across a layer 3 VPN from my ISP. Here is the config that I have and what I have done so far, but the phones at the remote site will not register with the phone system.

Cisco 2431 IAD at each location
Linksys WRT54GX-V2 at Host site
Linksys WRT150N at Remote site

2431 at each location has two ethernet ports. One is for internet and the other is for the VPN.

The Linksys at each location is set as the gateway.

Remote site config -
Phone IP - 192.168.0.135
Phone Gateway - 192.168.0.4
Phone DRS IP - 192.168.1.134
Linksys internal IP - 192.16.0.4
Cisco VPN IP - 192.168.0.254
Linksys WAN IP - 66.something
Cisco internet IP - 66.something

Host site config -
Phone system VOIP card IP - 192.168.1.134
Phone system VOIP gateway 192.168.1.4
Linksys ethernet IP - 192.16.1.4
Cisco VPN IP - 192.168.1.254
Linksys WAN IP - 64.something
Cisco internet IP - 64.something

The Linksys on each end have a default route to the Cisco internet IP and a static route built for all 192.168.0.0(host) and 192.168.1.0(remote) traffic to point to the VPN gateway.

From a PC on the network at the remote location, I can do a tracert to the VOIP card and it routes across the VPN no problem. From a PC on the network at the host site, I can do a tracert to a phone at the remote site across the VPN no problem.

I'm starting to think this is not going to work through the Linksys and I am going to have to point the phones directly at the VPN gateway and bypass the Linksys all together.

Does anyone know if this will work using the Linksys router as a gateway?

It would be helpful if you could draw a diagram and post it.

I think the answer to your question is yes. Why not try it and see? And let us know.

My first impression is that something in your Linksys router is blocking SiP.

The first problem I see with this config is that you have the DRS of the IP phone pointing to the VoIP Card in the Aspire at the main site. It should be pointing to the NTCPU (CPU) of the Aspire at the main site. Both the NTCPU and the VoIP card must have a static IP (192.168.x.x). When you power on the remote IP phone it contacts the NTCPU to get it's settings, extension number etc. When a call is placed the NTCPU rings the phone sends the Caller ID, etc. When the handset is lifted the NTCPU hands the call off to the VoIP card for Voice transmission. Hope this helps.

Sorry for the late update and thanks for the help!

I went back out the next morning after I dreamed about it all night. Changed the IP of the DRS to the CPU of the Aspire. Then next, I had to set the gateway on the phones to the VOIP card. With the VOIP card being 192.168.1.134 and the phones being 192.168.0.x, I had to set the subnet to 255.255.0.0 so it would work. The phones immediately came up.

I think the overall problem was the phone vendor had never set this up across a layer 3 vpn.

The other issue after I came into the picture, is being a data guy, If someone says gateway to me, my mind thinks networking and I use the IP of the first hop in this case the internal IP of the Linksys.

Anyway, it is working now and I'm off to something else.

The VOIP phones shouldn't need the gateway programmed in just the primary DRS. The VOIP card only comes into the picture on non-IP calls