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GRE Tunneling

Dear Experts,

Working in my testing environment I have connected two IP GRE tunnels.

Tunnel 1 - Tunnel between two 3550 IOS 12.1(22).

Tunnel 2 - Tunnel between two 2800 IOS 12.4(4a).

While working with both tunnels I have noticed few major differences.

a. Speed ? The connection between two 2800 routers is much faster then the 3550.

b. Fast Tunneling ? 2800 router has an option of "fast tunneling" while the 3550 doesn't have this option.

c. IP CEF ? doesn't 3550 use IP CEF? What is the effect on the GRE connection without IP CEF?

Why the two GRE tunnels are so different? Is there a way to get better results with the 3550?

I hope you can help me

Tzachi Slav

Hall of Fame Super Gold

Re: GRE Tunneling


You do not tell us anything about the connections between the 3550s or about the connections between the 2800s. It is possible that there are differences in the connections that would explain part of the performance difference that you describe. Can you clarify the connectivity? It would also be helpful to see configuration details from all devices so that we could see if there is some configuration difference that might explain some of the difference.

Another point is that there are significant differences in the IOS that you are running. I am confident that the difference in the 2800 option of fast tunneling not being on the 3550 reflects the differences between 12.1(22) and 12.4(4a). If you get roughly equivalent IOS on both types of devices you are likely to have the same options (and perhaps closer to the same performance).



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