Internet Engineering Task Force R. Droms
Internet-Draft Cisco
Updates: RFC 4291 (if approved) November 04, 2013
Intended status: Standards Track
Expires: May 08, 2014

IPv6 Multicast Address Scopes
draft-ietf-6man-multicast-scopes-01.txt

Abstract

This document updates the definitions of IPv6 multicast scopes.

Status of This Memo

This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet-Drafts is at http://datatracker.ietf.org/drafts/current/.

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This Internet-Draft will expire on May 08, 2014.

Copyright Notice

Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved.

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1. Definition of IPv6 Multicast Address Scopes (Updates RFC 4291)

RFC 4291 [RFC4291] defines "scop is a 4-bit multicast scope value used to limit the scope of the multicast group." scop 3 is defined as "reserved" in RFC 4291. The multicast protocol specification in draft-ietf-roll-trickle-mcast [I-D.ietf-roll-trickle-mcast] desires to use multicast scop 3 for transport of multicast traffic scoped to a network of nodes connected in a mesh. The use of this scop value is to accommodate a multicast scope that is greater than Link-Local but is also automatically determined by the network architecture; for example, all of the hosts and routers in a multi-link subnet RPL realm.

The following table updates the definitions in RFC 4291:

0
reserved
1
Interface-Local scope
2
Link-Local scope
3
Realm-Local scope
4
Admin-Local scope
5
Site-Local scope
6
(unassigned)
7
(unassigned)
8
Organization-Local scope
9
(unassigned)
A
(unassigned)
B
(unassigned)
C
(unassigned)
D
(unassigned)
E
Global scope
F
reserved

OLD:

      Admin-Local scope is the smallest scope that must be
      administratively configured, i.e., not automatically derived
      from physical connectivity or other, non-multicast-related
      configuration.

NEW:

      Interface-Local, Link-Local, and Realm-Local scope
      boundaries are automatically derived from physical
      connectivity or other, non-multicast related configuration.
      Global scope has no boundary.  The boundaries of all other
      non-reserved scopes of Admin-Local or larger are
      administratively configured.  For reserved scopes, the way
      of configuring their boundaries will be defined when the
      semantics of the scope is defined.

      According to RFC 4007 [RFC4007], the zone of a Realm-Local
      scope must fall within zones of larger scope.  Because the
      zone of a Realm-Local scope is configured automatically,
      while the zones of larger scopes are configured manually,
      care must be taken in the definition of those larger scopes
      to ensure that inclusion contraint is met.


        

The following change is applied to section 2.7 of RFC 4291:

2. Definition of Realm-Local scopes

The definition of any Realm-Local scope for a particular network technology should be published in an RFC. For example, such a scope definition would be appropriate for publication in an "IPv6-over-foo" RFC.

Any RFCs that include the definition of a Realm-Local scope will be listed in the IANA "IPv6 Multicast Address Scopes" registry.

3. Definition of automatic and administratively configures scopes (updates RFC 4007)



OLD:

  o  The boundaries of zones of a scope other than interface-local,
     link-local, and global must be defined and configured by network
     administrators.

NEW:

  o  The boundaries of zones of a scope are defined by the IPv6
     addressing architecture [RFC4291].

        

Section 5 of RFC 4007 [RFC4007] and section 2.7 of RFC 4291 disagree about the way in which multicast scope 3 is configured. To resolve that disagreement, change the last bullet in the list in section 5 of RFC 4007 as follows:

4. IANA Considerations

IANA is asked to establish a sub-registry titled "IPv6 Multicast Address Scopes" in the existing "Internet Protocol version 6 (IPv6) Multicast Address Allocations" registry. The "IPv6 Multicast Address Scopes" is to be populated with the scope values given in section 1, with a note associated with scope 3 listing all RFCs that define Realm-Local scoping rules that use scope 3.

5. Acknowledgments

Robert Cragie, Kerry Lynn, Jinmei Tatuya, Dave Thaler and Stig Venaas all contributed to enuring that the updates to RFC 4007 and RFC 4291 are correct

6. Security Considerations

This document has no security considerations beyond those in RFC 4291 [RFC4291].

7. References

7.1. Normative References

[RFC4007] Deering, S., Haberman, B., Jinmei, T., Nordmark, E. and B. Zill, "IPv6 Scoped Address Architecture", RFC 4007, March 2005.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 4291, February 2006.

7.2. Informative References

[I-D.ietf-roll-trickle-mcast] Hui, J. and R. Kelsey, "Multicast Protocol for Low power and Lossy Networks (MPL)", Internet-Draft draft-ietf-roll-trickle-mcast-04, February 2013.

Author's Address

Ralph Droms Cisco 1414 Massachusetts Avenue Boxborough, MA 01719 US Phone: +1 978 936 1674 EMail: rdroms@cisco.com

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