Re: question regarding draft-ietf-6man-rfc3484-revise-02 section 2.3

Mikael Abrahamsson <swmike@swm.pp.se> Mon, 28 March 2011 12:35 UTC

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Date: Mon, 28 Mar 2011 14:36:51 +0200 (CEST)
From: Mikael Abrahamsson <swmike@swm.pp.se>
To: ipv6@ietf.org
Subject: Re: question regarding draft-ietf-6man-rfc3484-revise-02 section 2.3
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On Mon, 28 Mar 2011, Brian Haberman wrote:

> Hi Mikael,
>
> On 3/28/11 4:25 AM, Mikael Abrahamsson wrote:
>>
>> Hello.
>>
>> I read through 2.3 of the draft, and I am a bit unclear as to how the
>> next-hop should be selected.
>>
>> In the case of my SLAAC machine, I see the next-hop for my default-route
>> as a LL address. How would the SA and the default router LL be tied
>> together?
>
> One way would be for the stack to keep track of which router's LL
> address was the source of the PIO containing the prefix used to generate
> the address.

I realise this is a possibility, but shouldn't there be a mention in the 
draft of recommended mechanisms to achieve this goal?

>> In the case of getting address using DHCPv6, there is also no direct
>> connection between the default route and the SA, as the DHCPv6 server
>> might be different from the default-route gw?
>
> Does the DHCPv6 response contain any information about the DHCP-relay used?

If the DHCPv6 server is just local to the network and doesn't use a relay?

Afaik there has been a deliberate decoupling of stateful DHCPv6 and SLAAC 
so as to make DHCPv6 not able to hand out a default routes, so I don't 
really see how this coupling can be done again with the basic mechanisms 
available today?

In v6ops I was pointed to BRDP 
<http://tools.ietf.org/html/draft-boot-brdp-based-routing-00> which is an 
expired draft, I believe a mechanism like this is needed to properly 
achieve the goal of correct default route for certain SA. I don't really 
see how it can be done otherwise.

-- 
Mikael Abrahamsson    email: swmike@swm.pp.se