Our service provider we use to connect to a remote office wants to bill us an extra 1000 a month to allow us to send tagged traffic over the circuit. seems like a lot of money to add the line "switchport mode dot1q-tunnel " to the ports config.
are there any solutions which will allow us to pass tagged traffic between offices without paying the service provider to allow double tagging? Routing is not an option as we have to pass vlans (voice/video) which we do not administrate.
IMHO, the GRE would probably be the least painful, as long as both ends can see each other, you have a link.
You can also track it for lighting up a backup path, if necessary.
A site-to-site VPN is a little trickier, but it is also normally encrypted (the GRE usually isn't, I believe), so if security is critical, you'd need to add encryption to eh GRE, or just go with the VPN.
It should be easy enough to check out one against the other for a final judgment.