We're looking at pulling in two T1s and aggregating the bandwidth so that we have one big pipe. So far I've been getting different information depending on what ISP I talk to on what's involved in doing this. So far I've been told I need to MLPPP, but I have to buy a Tasman router to do it, then I was told MLPPP will work on the 7140 router that I currently have, then someone else told me to use CEF.
Any ideas on which is the best way to go?
MLPPP and CEF per-packet load balancing are the most common techniques, and are supported by the majority of Cisco routers out there. I'm not familiar with the 7140's, however.
Both MLPPP and CEF per-packet will do what you want. MLPPP will combine the T1's into a single virtual link, while CEF will just load share the traffic between the two links on a per-packet basis (you can also do so-called per-destination which is really per-source/destination pair). I don't find one solution to be inherently better than the other, so if your router supports both you can try them both and see if you like one more than the other.