Joseph W. Doherty Thu, 11/13/2008 - 13:19

If the VTI (virtual tunnel interface) you're thinking of is the one used by IPSec, it would seem to have more overhead and more configuation than just GRE. Or where you thinking VTI vs. IPSec/GRE tunnel?

cedar_lee Thu, 11/13/2008 - 13:52

Yes, you are right. GRE over IPsec. Thanks for correcting me.

Michal Gurbski Sat, 05/08/2010 - 04:47


GRE headers  adds extra 4 bytes, thus reducing the bandwidth for sending encrypted data.

See attachment.

And info from

"The main difference is that VTIs only support IP (unicast and multicast), while GRE also supports other protocols. VTIs also were not available on all platforms when they were first introduced."

Kind regards,



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