[Update] Re: New ISP to market, BCP 38, and new tactics

Nathan Ward nanog at daork.net
Wed Feb 4 01:51:16 UTC 2009

On 4/02/2009, at 2:43 PM, Steve Bertrand wrote:

> Nathan Ward wrote:
>> On 4/02/2009, at 2:33 PM, Steve Bertrand wrote:
>>> - Currently, (as I write), I'm migrating my entire core from IPv4 to
>>> IPv6. I've got the space, and I love to learn, so I'm just lab-ing  
>>> it up
>>> now to see how things will flow with all iBGP v4 routes being
>>> advertised/routed over v6.
>> Don't advertise v4 prefixes in v6 sessions, keep them separate.
>> If you do, you have to do set next-hops with route maps and things,  
>> it's
>> kind of nasty.
>> Better to just run a v4 BGP mesh and a v6 BGP mesh.
> Ok. I've been having problems with this.
> What I was hoping for (even though I'm testing something that I know
> won't work) is that I can break something so I could push v4 traffic
> over a v6-only core.
> Is there _any_ way to do this (other than NAT/tunnel etc)?

MPLS - "The MP is for Multi Protocol!"

Otherwise, no, you don't get to use IPv6 addresses as next hops for  
IPv4 routes, which I think is what you're asking to do.

Run IPv4 and IPv6 in parallel, iBGP for v4, iBGP for v6. Same for eBGP  
to peers/customers.
Running v4 and v6 in one BGP session is weird and is asking for  
confusion, IMHO.

You get the same with OSPF - you run OSPFv2 and OSPFv3 in parallel.

Nathan Ward

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