Identifying IPv6 Interfaces in Link-Local Addresses

Document Type Expired Internet-Draft (ipngwg WG)
Author Robert Elz 
Last updated 1996-05-06
Stream Internet Engineering Task Force (IETF)
Intended RFC status (None)
Expired & archived
pdf htmlized (tools) htmlized bibtex
Stream WG state WG Document
Document shepherd No shepherd assigned
IESG IESG state Expired
Consensus Boilerplate Unknown
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Responsible AD (None)
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This draft proposes a change to the way that IPv6 link local addresses are constructed, so that a node can guarantee that all of its link local addresses are unique within the node. The current definition of a link local address, a well known prefix, some number of zero bits, and a link specific unique token, ensures that it will be unique on the link, which is what is required for communications using those addresses over the link, but does not require uniqueness of the addresses within a node. In some cases all of a nodes interfaces may share the same link local address. Even the possibility of this means that link local addresses, which may in some situations be the only addresses that exist, cannot be used for internal definition of interfaces, or other purposes within the node. This draft suggests a method by which nodes may overcome this problem, by redefining the bits between the prefix and the token to be available to be used by the node to cause the addresses to be unique.


Robert Elz (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)