A client of mine has an Avaya IP403 VoIP system. I confess I am not very familiar with the unit, or any VoIP system, however because it has CAT5 cables attached, it seems to fall under IT :-)
There is one central IP403 with about 10 remote sites, each with it's own VPN, subnet, and a single Avaya IP phone. I have configured the VPN's with the supplied Linksys RV042's and the system seems to work fine. Every remote site can call the main office with their IP phone, and they can call any outside phone number without issue. However, no remote IP phone can contact an other IP phone at any of the remote sites. I assume this is a routing issue, but the support from the supplier is non-existent. "IP Routes" have been configured on the Avaya, but no "Logical LANs" or routing. There are also no VLANs, or VLAN or QOS capable switches, present at the main office site. I am told a softphone at one of the remote sites can talk to an IP phone at another site, but I have not verified this.
Can someone point me in the right direction as to why routing between the IP phones is not taking place. Does this need to be configured on the Avaya system, static routes on the local routers, or is it even possible with the existing hardware. I question whether they require routers capable of a hub and spoke VPN configuration, but I am out of my league here.