Subject: [I-D] IPv6 DAD Consideration for 802.11 Environment

From: 박수홍 <[email-masked]>
Date: Thu, 03 Jul 2003 16:10:20 +0900

Hi folks

Today, 802.11 technology is the most famous L2 tech in our market. and 
most guys agree that. However there are some problem to use an IPv6 address
autoconfiguration since 802.11 station can not detect duplicated address
with same MAC address.

Please let me  know your view on this.... I believe it should be considered
as one of node requirement...

http://home.megapass.co.kr/~natpp00/IPv6DADfor802.11.txt

1. Introduction

   In order to generate unique address, an IPv6 nodes has to perform
   DAD (Duplicate Address Detection) procedure when the IPv6 node tries
   to make its own IPv6 address including link-local and global address.
   If IPv6 node detects address duplication by Neighbor Advertisement
   message from duplicated node, then the duplicated address can not be
   used for this node, then IPv6 node MUST generate its own address by
   other mechanism like DHCP or Random Interface ID generation etc.
   Generally, address duplication is happened to the same Interface ID
   which is composed of 48bit/64bit MAC address. Therefore, when same 
   MAC address is existed in the same link, one of these nodes can not
   make its IPv6 address using address autoconfiguration mechanism.

   However, if the same MAC address is existed in the same link as 
   802.11, there are some problems and considerations for IPv6 address 
   autoconfiguration. IPv6 node in 802.11 environment will never be 
   able to receive the DAD packets if its MAC address is same as another
   node, because of the frame filtering based on the source MAC address.
   In this case the DAD always succeeds even though the addresses are 
   duplicate.

   This memo tries to consider above problem and suggest possible 
   solutions.
   
   Note that this consideration SHOULD be discussed at the IPv6 node
   requirements.

Daniel (Soohong Daniel Park)
Mobile Platform Lab. Samsung Electronics
TEL:+82-31-200-4508  FAX:+82-31-200-3147
mailto:[email-masked]

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From: Pekka Savola <[email-masked]>
Date: Sat, 5 Jul 2003 08:35:15 +0300 (EEST)

> as one of node requirement...

The purpose of DAD is not to detect MAC address duplication, but IP 
address duplication.

If MAC addresses are the same, there are likely to be other problems 
besides IP operations in the LAN (e.g. I don't know for sure how switches 
operate).

Perhaps this would speak for some form of applicability statement for DAD, 
to be clear what it is meant to solve and what it isn't.

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings