INE has a great blog on the IPv6 tunnels. You are correct concerning the overhead, but with the GRE IPv6 tunnel, the packet can carry additional data such as IS-IS.
http://blog.internetworkexpert.com/2009/08/28/ipv6-transition-mechanisms-part-2-greipv4-tunnels/
Hope this helps....
-----Original Message-----
From: nobody_at_groupstudy.com [mailto:nobody_at_groupstudy.com] On Behalf Of groupstudy_at_nyms.net
Sent: Tuesday, November 03, 2009 6:24 PM
To: ccielab_at_groupstudy.com
Subject: Tunnel mode ipv6 or tunnel mode gre ipv6?
Hi chaps,
What's the difference between running "tunnel mode ipv6" and "tunnel mode gre ipv6"? I'm working on a rented rack so I can't sniff.
Both appear to work as long as each side is running the same mode, but not intercompatible. Both encapsulate in IPv6 but I don't get the need for two methods of doing this.
I guess the easy answer is that the latter encapsulates into GRE before encapsulating into IPv6 - if that's the case, then why would anyone use that option which I assume adds extra size to the headers?
Can't find much on the Cisco site or Google other than this: Static tunnel interface configured to encapsulate IPv6 or IPv4 packets in IPv6.
Anyone help me out here? What am I missing?
THANKS!
Blogs and organic groups at http://www.ccie.net
Received on Tue Nov 03 2009 - 19:00:03 ART
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