Subject: [Mip6] I am still puzzled in DAD mechanism in mipv6

From: "Lee Garth" <[email-masked]>
Date: Thu, 25 Dec 2003 10:16:17 +0000

Hello to all:
    In a draft issued in July:draft-park-ipv6-dad-problem-wlan-00.txt
    The author says besides the time cost in the procedure that MN proceeds 
the DAD itself, there is mechanical deficiency in applying DAD in wireless 
environment.

    In chapter 2, it says:
     "In this case, IPv6 DAD will not be able to detect duplicate address
      in 802.11 environment because if am 802.11 end station recevies
      a DAD packet from a node which is having same MAC, the 802.11 end 
      station discards the frame and will not be able to defend the DAD.
      So the DAD always succeeds even though there are two end stations 
      with the same MAC address.
      Consequently, IPv6 node generates its address without any 
duplication,
      but this address is not unique address but duplicated address. This 
      concludes that "Multicast Packet Filtering based on Source Address" 
      makes  "Duplicate Address Detection" procedure trivial."

  This draft provides in Chapter 3.2 two possible solutions:
      * Enhanced Multicast Filtering at Layer 2
      * Selective Filtering at Layer 2
    
      But I don't see any subsequent draft concerning this defect and 
thinking over further implementations. All drafts and discussions I have 
read are about reducing the time cost in DAD procedure. Have it already 
been avoided or amended in draft24? What is the solution then? I would be 
very thankful if anyone here illuminates it to me.

      Happy Christmas to all....

                                                                Yours 
                                                                    
Garthdawn
           'spamcontrol '

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From: Jari Arkko <[email-masked]>
Date: Fri, 26 Dec 2003 11:35:14 +0200

Lee Garth wrote:

>    The author says besides the time cost in the procedure that MN proceeds the DAD itself, there is mechanical deficiency in applying DAD in wireless environment.
> 
>    In chapter 2, it says:
>      a DAD packet from a node which is having same MAC, the 802.11 end      station discards the frame and will not be able to defend the DAD. 
(snip)
> been avoided or amended in draft24? What is the solution then? I would 
> be very thankful if anyone here illuminates it to me.

I am not aware of any discussion regarding this, but it is possible
that DNA BOF/WG has discussed it. Greg?

Draft 24 certainly does not (and will not) address the defect that
you mention. The issue is not mobility specific. It might even be
a non-IETF problem.

--Jari