Question : Problem: Cisco VPN

What are the commands for creating a VPN tunnel from a Cisco 1721 IOS Version 12.2(7r)XM1, RELEASE SOFTWARE (fc1)
to a 2611 running IOS 12.3(5b) that also allows NETBIOS traffic?

Answer : Problem: Cisco VPN

Here is just about every combination for Cisco VPN setups: http://www.cisco.com/en/US/tech/tk583/tk372/tech_configuration_examples_list.html

About 1/3 of the way down, there's a router-router config using AES. You could also take a look at the router-router fully meshed configuration too.

As long as you are doing NetBIOS over TCP/IP, you should be fine. If you are not going to do NetBIOS over TCP/IP, you'll have to setup something like DLSW.

-Eric