I work with a company that has two ADSL lines, each coming into a Draytek 2820 router then into a load balancing Vigor 3300. The LAN address is 192.168.3.0 / 24. There's also VOIP on a separate 192.168.4.0 / 24 network and this network does not touch any of the Draytek/Vigor hardware as it doesn't need access to the internet. There's a subsidiary office that has 3 phones and we'd like to extend the VOIP network from the main office to the remote office for convenience and to reduce costs. The remote office has a LAN address 192.168.5.0 / 24. We don't need to share files, printers etc. between the main and remote offices at present but that might become necessary in due course.

I had hoped to connect the main and remote Draytek 2820s via a VPN then have the VOIP traffic connected to a separate VLAN which passes down the VPN but it seems that this isn't possible with the Draytek 2820s that we have. Does anyone have experience of any other Draytek models that could do what I need? Will the idea work or are there any other solutions? If we are going to set something up and save costs at the remote office (by cancelling renewal of the phone system), we could buy some new kit for both main and remote offices, if necessary.

I hope I've given enough information for some suitable solutions to be presented. If additional information is required, I'll happily provide it.

Thanks for your time.