Subject: draft-yhb-6man-nd-improvement-00

From: "Yu Hua bing" <[email-masked]>
Date: Thu, 24 Feb 2011 22:18:04 +0800

Hello, what do you think of this draft?

http://datatracker.ietf.org/doc/draft-yhb-6man-nd-improvement/
Abstract

   This document describes the improvement to neighbor discovery. When
   an IPv6 address is deleted on a node, the node will send a neighbor 
   advertisement with a "Deleted" flag set to all link-local nodes.
   If the IPv6 address has been configured on another node, and it is
   in duplicate state, it will perform DAD(Duplicate Address Detection)
   again. If DAD succeeds, the IPv6 address will be assigned to the  
   node.
   If the IPv6 address exists in the neighbor cache on the other nodes,
   when the neighbor advertisement with deleted flag set arrived, they 
   know the neighbor is unreachable and delete the neighbor cache entry.

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From: "Rémi Denis-Courmont" <[email-masked]>
Date: Thu, 24 Feb 2011 19:44:45 +0200

> Hello, what do you think of this draft?

It is far too easy for a node of the subnet to hijack an address by spoofing 
the deleted flag...

Besides, nodes often learn that they're going off-link too late to send the 
deletion notice anyway.

-- 
Rémi Denis-Courmont
http://www.remlab.info/
http://fi.linkedin.com/in/remidenis

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From: Vishwas Manral <[email-masked]>
Date: Thu, 24 Feb 2011 21:50:00 -0800

Hi Yu,

Sounds like a good small optimization to me.

Thanks,
Vishwas

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From: "Yu Hua bing" <[email-masked]>
Date: Fri, 25 Feb 2011 20:52:38 +0800

Thank you for your support.

--------------------------------------------------
From: "Vishwas Manral" <[email-masked]>
Sent: Friday, February 25, 2011 1:50 PM
To: "Yu Hua bing" <[email-masked]>
Cc: <[email-masked]>; "? ??" <[email-masked]>
Subject: Re: draft-yhb-6man-nd-improvement-00

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From: "Yu Hua bing" <[email-masked]>
Date: Sun, 27 Feb 2011 15:35:58 +0800

> It is far too easy for a node of the subnet to hijack an address by 
Suppose host c sends a neighbor advertisement with flag D set to cheat all 
other nodes
that IPv6 address A assigned to host A is deleted,when host B receives the 
neighbor
advertisement,do as follows:
(1)If the target address is a unicast address in duplicate state on the
receiving interface, host B SHOULD set the state of the unicast
address to tentative and perform DAD.DAD will fail.
(2)If the source address is not the unspecified address, the neighbor
cache will be searched for the target's entry. If appropriate
neighbor cache entry has been located, because the neighbor is
unreachable, host B SHOULD delete the neighbor cache immediately.Host B can 
re-learn
the MAC address of host A via neighbor discovery protocol when it needs to 
communicate
with host A.

> Besides, nodes often learn that they're going off-link too late to send 
In some cases, for example, unplugging the network cables, nodes can't send 
the
deletion notice.But in other cases, it is helpful.