Re: RS sending in draft-ietf-v6ops-ipv6-cpe-router-04

[Wojciech Dec <wdec@cisco.com>]

On 26/04/2010 15:13, "Philip Homburg" <pch-v6ops@u-1.phicoh.com> wrote:

> In your letter dated Mon, 26 Apr 2010 15:01:44 +0200 you wrote:
>> On 17/04/2010 11:53, "Philip Homburg" <pch-v6ops@u-1.phicoh.com> wrote:
>> 
>>> In your letter dated Fri, 16 Apr 2010 11:49:18 +0200 you wrote:
>>>> Which node needs the link local address of the CPE? The edge router or
>>>> the access node? (using draft-krishnan-6man-rs-mark-03 terminology)
>>>> 
>>>> Woj> Likely both: The edge router is expected to have an address binding
>>>> table per CPE and so may the access-node.
>>> 
>>> Maybe I'm missing something. I would expect the edge router to maintain a
>>> mapping from prefix to vlan. It can then use normal neighbor discovery to
>>> find the mac address for a CPE.
>> 
>> That's not what is envisaged in the BBF and SAVI work. The L2-IP binding
>> would be learned at user authentication time and likely fixed so as to
>> prevent some rogue user from polluting the binding table.
> 
> The MAC address is available as the source ethernet address in the router
> solicitation.
> 
> How does having a link-local IPv6 address help?

It helps in being able to bind the MAC to an IPv6 address for that
subscriber. Coincidentally, this is exactly what is already in place for v4.

> 
> Unless, with L2-IP binding you mean a binding between the link-local address
> and the MAC address. But I'm not quite sure why you would need that.
> 
Without such a binding, LL spoofing becomes an issue.

-Woj.
>