Clarification on IPv6 Dual Stack approach

[news2010a]

Hi folks,

My understanding is that if one is planning migration to IPv6 and service provider is supporting Dual Stack, I could connect my PE router using:

1. GRE tunnel (which a static configuration method)

2. Manually Configured tunnels (MCT) which is also static.

I could do ISATAP and 6to4 but it sounds those are more complicated to implement. So I will stick with "static" options above.

Question:

a)Is it right that GRE  pros when compareted to MCT is that it supports passage of protocols such as IS-IS and others. Cons is that GRE adds certain overhead. That is about it, right?

b)if objective is to get company border router able to communicate via IPv6 with service provider, do you see any need to use ISATAP or 6to4 (dynamic tunnels)?

[Maarten Vervoorn]

I would stick to the use a GRE tunnels you are more flexible with that. Its only 24 bytes of overhead but you can solve fragmentation issue with lowering the MTU size on the tunnel interface.

Running dual stack by the way is not creating a IPv6 overlay network with tunnels. You can also run IPv4 and IPv6 on the interface on the same time. Connect to the other router with IPv6 and IPv4 so both solutions will work. If the provider isn't providing a IPv6 connections you can use GRE tunnels.