Analysis of the 64-bit Boundary in IPv6 Addressing

Document Type Replaced Internet-Draft (6man WG)
Authors Brian Carpenter  , Tim Chown  , Fernando Gont  , Sheng Jiang  , Alexandre Petrescu  , Andrew Yourtchenko 
Last updated 2014-03-26 (latest revision 2014-02-05)
Replaced by RFC 7421
Stream Internet Engineering Task Force (IETF)
Intended RFC status (None)
Expired & archived
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Stream WG state Adopted by a WG
Document shepherd No shepherd assigned
IESG IESG state Replaced by draft-ietf-6man-why64
Consensus Boilerplate Unknown
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


The IPv6 unicast addressing format includes a separation between the prefix used to route packets to a subnet and the interface identifier used to specify a given interface connected to that subnet. Historically the interface identifier has been defined as 64 bits long, leaving 64 bits for the prefix. This document discusses the reasons for this fixed boundary and the issues involved in treating it as a variable boundary.


Brian Carpenter (
Tim Chown (
Fernando Gont (
Sheng Jiang (
Alexandre Petrescu (
Andrew Yourtchenko (

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