Re: [v6ops] I-D Action:draft-ietf-v6ops-ipv6-cpe-router-bis-00.txt

[Brian E Carpenter <[e-mail]>]

On 2011-03-23 12:44, Hemant Singh (shemant) wrote:
> -----Original Message-----
> From: Brian E Carpenter [mailto:[e-mail]] 
> Sent: Tuesday, March 22, 2011 6:31 PM
> To: Hemant Singh (shemant)
> Cc: Mikael Abrahamsson; IPv6 Ops WG
> Subject: Re: [v6ops] I-D Action:draft-ietf-v6ops-ipv6-cpe-router-bis-00.txt
> 
> 
>> I agree. BRDP is far from cooked as an IETF solution. Shim6 is standardised,
>> but requires no special action by the CE router anyway.
> 
> Ah, OK.  Sorry, I am behind on my reading and shim6 is one specification I have to go thru.  Anyone deploy shim6 yet in any SP/edge network?

Only hosts deploy shim6 - there is nothing for router vendors or operators to do!

>> I assume you are now talking about a future draft and not about
>> cpe-router-bis?
> 
> I do think so - draft-cpe-router-ter should deal with multihoming and graphed routed topologies.  The reason is because the bis document is gestating to a critical mass for new requirements that would be worth publishing.  The routing section in section 5.4 has reached rough consensus in this mailer for text.  DNS is something we have to work on a bit.  Thereafter we could submit the bis document for LastCall.
> 
>> Again - this topic (and your analysis, if it's correct) seems to me to
>> belong in the multihoming-without-nat66 draft.
> 
> Ah, OK.  
> 
>> As I said a long time ago when MIF was first discussed, it seems that what
>> we need is to replace the concept of "default router" in the host stack
>> with a concept of "default router per prefix".
> 
> When a host has to forward a packet to a destination, the destination is either on-link (if the destination matches a prefix in the host's ND Prefix List) or off-link that means the packet is shipped to default router(s).  Thus all I can see is a default routers(s) per destination, not prefix.   Note the MSR is a construct that can map a prefix to a default router where the default router in the router that sent the RA with the MSR. 

To avoid ingress filters, you have to hit the right exit router. The easiest
way to do that is to select the default router according to the *source*
prefix of the packet. MIF is talking about having a default router per
interface; I think the model has to be stronger, and make it per prefix.
You definitely need a strong host model of some kind. But at the moment
this isn't well defined, so v6ops can't specify it.

   Brian