ipv6 , eui-64 & interface ID

[aqusingh7]

I know how to get the interface ID from a mac BUT whats that goto do with the eui-64 address obtained from a ipv6 128 bit address? So why would I use the 64 bit ipv6 address when working with the interface ID?

[Giuseppe Larosa]

Hello Baljit,

>> So why would I use the 64 bit ipv6 address when working with the interface ID?

That is the host portion.

the eui-64 is a sort of abstraction of MAC addresses and is the result of a transformation o the 48 bits MAC address by adding two bytes.

As a result of this an eui-64 compliant prefix is a /64 with 64 bits of network and 64 bits of host part where the eui-64 is placed.

Link local addresses use the eui-84 standard for example and it is quite common to use eui-64 addresses on lan also for unicast global addresses

see

http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-addrg_bsc_con.html#wp1038809

and

http://rfc-ref.org/RFC-TEXTS/4291/chapter2.html#d4e441801

Hope to help

Giuseppe

[jimmysands73_2]

I found this article helpful:

http://packetlife.net/blog/2008/aug/04/eui-64-ipv6/