Lan to Lan VPN speed degradation

[dpatkins]

Scenario:

Lan to Lan between two devices. Speed test is almost 75% lower in L2L than "normal". Is there a way to speed up the Lan to Lan? Can you do MTUs on a group? I have seen it on the defautl interfaces, but this is it.

Any help would be appreciated.

[ssoberlik]

Yes, VPN tunnel can be slowed if a lot of fragmentation is happening at the tunnel entry points. You need to tune the MTU accordingly so that minimal fragmentation occurs.

This Cisco documentation in an excellent resource on Fragmentation and MTU configuration.

http://www.cisco.com/en/US/tech/tk827/tk369/technologies_white_paper09186a00800d6979.shtml

[aacole]

Depending on your router hardware you may be able to use hardware based STAC compresion, this may offer a speed benefit.

What are the routers your using?