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A Recommendation for IPv6 Address/Mask Notation

Document Type Expired Internet-Draft (individual)
Expired & archived
Authors Igor Lubashev , Erik Nygren
Last updated 2018-04-30 (Latest revision 2017-10-27)
RFC stream (None)
Intended RFC status (None)
Stream Stream state (No stream defined)
Consensus boilerplate Unknown
RFC Editor Note (None)
IESG IESG state Expired
Telechat date (None)
Responsible AD (None)
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft is available in these formats:


Since network operators are commonly assigned at least /48 IPv6 address prefixes, the operators and standards occasionally find opportunities to devise addressing schemes that further assign operational semantics to less significant bit ranges. There is currently no standard or interoperable textual representation of addresses sharing bit patterns that are not prefixes. This RFC introduces IPv6 Address/Mask notation that allows one to represent address groupings beyond "all addresses that share a single prefix". The representation is similar to the IPv4 address/mask notation in its expressiveness, but it is derived from the familiar address/ prefix-length notation for clarity and compatibility with existing parsers. For example, using this representation, both 2001:db8::/32 and 2001:db8:://ffff:ffff:: have the same meaning. However, a group of addresses having the first 32 bits "2001:0db8::" and the last 16 bits "::1234" requires the new representation: 2001:db8::1234//ffff:ffff::ffff or, equivalently, 2001:db8::1234//32+::ffff.


Igor Lubashev
Erik Nygren

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