Tatuya,
Thanks for agreeing with our suggestion to not silently discard the
advertisement. The new paragraph from you is still not complete because you
have missed the part when a match of target address is not found in the
receiving interface, then the NA has to be processed as per 2461bis. Vlad has a
correct point too about anycast addresses - note section 5.4 of 2462bis says
"Duplicate Address Detection MUST NOT be performed on anycast addresses". Here
is the new text suggested by us:
On receipt of a valid Neighbor Advertisement message on an interface,
node behavior depends on whether the target address matches a unicast
address assigned (tentative or not tentative) to the interface. If the
target
address matches, then the address is not unique. The advertisement
SHOULD be discarded and the node SHOULD log a system management error.
The situation should be handled manually by the system administrator.
If the target address does not match, then the advertisement is
processed as described in [ID.ietf-ipv6-2461bis].
- Hemant and Wes
-----Original Message-----
From: Vlad Yasevich [mailto:[EMAIL PROTECTED]
Sent: Friday, July 06, 2007 8:44 AM
To: JINMEI Tatuya / ????
Cc: Hemant Singh (shemant); Suresh Krishnan; [email protected]
Subject: Re: Revisit: one remaining corner case in DAD
JINMEI Tatuya / 神明達哉 wrote:
> In conclusion I'd like to propose to change the paragraph of Section
> 5.4.4 from:
>
> On receipt of a valid Neighbor Advertisement message on an interface,
> node behavior depends on whether the target address is tentative or
> matches a unicast or anycast address assigned to the interface. If
> the target address is assigned to the receiving interface, the
> solicitation is processed as described in [I-D.ietf-ipv6-2461bis].
> If the target address is tentative, the tentative address is not
> unique.
>
> to:
>
> On receipt of a valid Neighbor Advertisement message on an interface,
> node behavior depends on whether the target address is tentative or
> matches a unicast or anycast address assigned to the interface. If
> the target address is assigned to the receiving interface, the
> advertisement SHOULD be discarded and the node SHOULD log a
> system management error; this case would indicate that the address
> is a duplicate but it has not been detected by the Duplicate
> Address Detection procedure, which should be manually handled by
> the system administrator. If the target address is tentative, the
> tentative address is not unique.
>
> (the additional note "this case would indicate..." may sound too
> verbose. If so, I'm willing to remove it.)
>
> Does this make sense?
The only part of the above paragraph that I keep questioning is
the inclusion of anycast. I thought that it was perfectly fine
to have duplicate anycast addresses on the same link and 2461bis still permits
that.
So I would change start the second sentence of the above paragraph
as: "If the target address is a unicast address assigned to the receiving
interface, ..."
Thanks
-vlad
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