I will be installing two 2811 routers with four dedicated (point-to-point) T1 connections.
Is it better (faster) to use Multilink PPP, IP CEF, or can I use a combination of both?
Well, CEF is a switching mechanism. IOS supports a number of switch mechanisms:
- process-switching - CPU-intensive
- fast-switching - less CPU-intensive
- CEF-switching - highly optimised.
So you are going to be using one of the above, for sure. It's better to enable CEF and to use that since it performs much better than any of the other methods. In fact, in newer IOSes, it should be enabled by default.
CEF is also required for a number of other things like QoS marking and NBAR. The bottom line is that you have so much to gain and so little to lose by enabling CEF.
Enable it using: 'ip cef'
Hope that helps - pls rate the post if it does.