Hello again folks,
It seems like I recall seeing a complaint by Christopher Dearlove to the
effect that RFC 6621 is simply inapplicable to AODVv2. Is that comment
something I should respond to on the mailing list?
I am re-sending the attached draft to show just how wrong his complaint
is. Please let me know if you have any comments.
I sent it out earlier (on November 26 of last year) but did not get any
comments. It's very short. Please take a look.
Regards,
Charlie P.
Mobile Ad Hoc Networks [manet] C. Perkins
Internet-Draft Futurewei
Expires: May 29, 2016 November 26, 2015
Using Layer 3 Multicast Suppression Protocols Above Layer 3
draft-perkins-manet-using-RFC6621-00.txt
Abstract
This document specifies how protocols operating at layers above layer
3 can use the multicast suppression algorithms, for instance the
algorithms specified in RFC 6621.
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/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on May 29, 2016.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Perkins Expires May 29, 2016 [Page 1]
Internet-Draft Using RFC6621 November 2015
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Use of multicast suppression algorithms above Layer 3 . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
6. Informative References . . . . . . . . . . . . . . . . . . . 3
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
Limiting the number of multicast forwarders provides performance
benefits when used with a protocol that relies on flooding messages
throughout a network. Such multicast suppression methods for
limiting the number of multicast forwarders while maintaining
complete network coverage are specified in RFC 6621 [RFC6621].
Routing protocols can offer much greater performance using RFC 6621
algorithms. These algorithms do not affect the origination of
multicast messages, but only determine whether a node needs to
forward incoming multicast messages that are intended to flood the
network. In fact, enabling this performance benefit for reactive
manet routing protocols was a strong motivating factor in the
development and publication of RFC 6621.
RFC 6621 multicast suppression algorithms are specified to operate at
layer 3. Manet routing protocols use RFC 5444 [RFC5444] as a message
bundling layer; they operate above layer 3. Such protocols specify
that incoming multicast control messages have to be processed before
regeneration; in other words, the incoming multicast message is not
forwarded at all. Manet control messages are sent with the IP
destination address set to the link-local multicast address LL-MANET-
Routers [RFC5498] unless otherwise specified. This document
specifies a way to use layer 3 multicast suppression algorithms at a
layer above layer 3 so that algorithms that require network-wide
flooding can reap the benefits of the multicast suppression
algorithms.
2. Terminology
This document defines the following terminology:
Forwarding Node
A node that currently forwards incoming multicast messages to its
neighbors, based on the results of running a multicast suppression
algorithm.
Multicast Suppression Algorithm
Perkins Expires May 29, 2016 [Page 2]
Internet-Draft Using RFC6621 November 2015
An algorithm that determines which multicast routers are required
for complete coverage of a multicast group; retransmission by
other multicast routers for the multicast group is unnecessary.
Some layer 3 multicast suppression algorithms are specified in RFC
6621.
Regeneration
Transmission of a message formed by processing and modification of
an incoming message for an operation requiring the attention of
members of a multicast group.
3. Use of multicast suppression algorithms above Layer 3
If the node is not currently a multicast forwarding node, then the
node does not regenerate multicast messages even if the conditions
for regeneration are satisfied. This restriction only applies for
regeneration, and does not apply to multicast messages originated by
the node.
For example, if an AODVv2 [I-D.ietf-manet-aodvv2] router is not
currently a multicast forwarding node, then it does not regenerate
multicast messages (e.g., RREQ or RERR) even if the conditions for
regeneration are satisfied. This restriction only applies for
regeneration, and does not apply for multicast RREQ or RERR messages
originated by the node.
4. Security Considerations
This document does not introduce any security mechanisms, and does
not have any impact on existing security mechanisms.
5. IANA Considerations
This document does not specify any IANA actions.
6. Informative References
[I-D.ietf-manet-aodvv2]
Perkins, C., Ratliff, S., Dowdell, J., Steenbrink, L., and
V. Mercieca, "Ad Hoc On-demand Distance Vector Routing
Version 2 (AODVv2)", draft-ietf-manet-aodvv2-12 (work in
progress), October 2015.
[RFC5444] Clausen, T., Dearlove, C., Dean, J., and C. Adjih,
"Generalized Mobile Ad Hoc Network (MANET) Packet/Message
Format", RFC 5444, DOI 10.17487/RFC5444, February 2009,
<http://www.rfc-editor.org/info/rfc5444>.
Perkins Expires May 29, 2016 [Page 3]
Internet-Draft Using RFC6621 November 2015
[RFC5498] Chakeres, I., "IANA Allocations for Mobile Ad Hoc Network
(MANET) Protocols", RFC 5498, DOI 10.17487/RFC5498, March
2009, <http://www.rfc-editor.org/info/rfc5498>.
[RFC6621] Macker, J., Ed., "Simplified Multicast Forwarding",
RFC 6621, DOI 10.17487/RFC6621, May 2012,
<http://www.rfc-editor.org/info/rfc6621>.
Author's Address
Charles E. Perkins
Futurewei Inc.
2330 Central Expressway
Santa Clara, CA 95050
USA
Phone: +1-408-330-4586
Email: charliep@xxxxxxxxxxxx
Perkins Expires May 29, 2016 [Page 4]
