Solved: GRE IPV6 Confusion!

lowfell · ‎06-19-2017

I need some clarity on this type of GRE configuration

Configuration of R3:
!
interface Tunnel34
no ip address
ipv6 address 2026::34:1/122
ipv6 enable
ipv6 ospf 6 area 34
tunnel source Serial0/0/0.34
tunnel destination 10.1.1.10
tunnel mode ipv6

@@@@@@@@@@@@@@@

1. What type of tunnel is this? is it plain old tunnel, and in that case is in that case is is still necessary to have

tunnel mode ipv6 ?

2. Is it an ipv6 tunnel and the tunnel mode needs to be #tunnel mode ipv6 ?

3. Is it always mandatory to have a tunnel mode ?

4. what is the difference between #tunnel mode gre ipv6

& #tunnel mode ipv6 ?

Thanks in Advance

Philip D'Ath · ‎06-19-2017

Correct.

View solution in original post

Philip D'Ath · ‎06-19-2017

It is tunnelling IPv6 over IPv4.

Philip D'Ath · ‎06-19-2017

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/interface/configuration/xe-3s/ir-xe-3s-book/ip6-man-tunls-xe.pdf

lowfell · ‎06-19-2017

It is tunnelling IPv6 over IPv4

So in this instance is it mandatory to have #tunnel mode ipv6 ?

Philip D'Ath · ‎06-19-2017

It has to match the remote end - and it has to be a type that tunnels IPv6.

So you could use a different IPv6 tunnel mode - but you must have one.

lowfell · ‎06-19-2017

So if its R1#tunnel mode ipv6

then the other side has to be R2#tunnel mode ipv6 ?

Or R1#tunnel mode gre ipv6

R2#tunnel mode gre ipv6 or whatever as long as they match?

Philip D'Ath · ‎06-19-2017

Correct.

lowfell · ‎06-19-2017

Thanks Philip. That's much appreciated.