Issue about IPV6 Stateless auto-config

Unanswered Question
Nov 7th, 2009
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Hi,

I have this link local adress:

FE80::A1:2345:6789

and this router global adress:

2001:AAAA:BBBB:CCCC:DDDD::1/64


What is the statless autoconf global unicast address of my station?

2001:AAAA:BBBB:CCCC::A1:2345:6789

or

2001:AAAA:BBBB:CCCC:FE80::A1:2345:6789


Thanks

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Overall Rating: 3 (2 ratings)
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Nagendra Kumar ... Sun, 11/08/2009 - 06:36
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Hi,


The RA (Router Advertisement) message sent by IPv6 router will have the prefix which you mention using "ipv6 nd prefix-advertisement" command with autoconfig bit set. This prefix normally will be the global unicast prefix.


In your case, if the RA sends 2001:AAAA:BBBB:CCCC/64 prefix, the receiving node will concatenate its interface identifier and make it a 128 but address and assign the same to the interface.


For example, if the MAC address of your interface is XXXX.YYYY.ZZZZ, the interface identifier will be XXXX.YYFF.FEYY.ZZZZ and the ipv6 address will be 2001:AAAA:BBBB:CCCC:XXXX.YYFF.FEYY.ZZZZ


HTH,

Nagendra

qudatheocelbatran Sun, 11/08/2009 - 20:08
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Your recommended choice is not available in my test/quizz. Thanks anyway.


Any other opinions pls ?

Giuseppe Larosa Mon, 11/09/2009 - 04:04
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Hello Theodor,

the answer that has been provided to you by Nagendra is the correct one.


You should take in consideration the fact that your test/quiz can be wrong.


Note also that providing a rating of 1 in these forums is regarded as unfair and in this case it is.


read by yourself ipv6 basic addressing guide about stateless autoconfiguration


http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-addrg_bsc_con.html#wp1038169


it is IPV6 prefix /64 + EUI associated to device NIC mac address


EUI is a 64 bits entity derived from MAC address


Hope to help

Giuseppe


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