Directional Airtime Metric Based on Packet Sequence Numbers for Optimized Link State Routing Version 2 (OLSRv2)
RFC 7779
Internet Engineering Task Force (IETF) H. Rogge
Request for Comments: 7779 Fraunhofer FKIE
Category: Experimental E. Baccelli
ISSN: 2070-1721 INRIA
April 2016
Directional Airtime Metric Based on Packet Sequence Numbers for
Optimized Link State Routing Version 2 (OLSRv2)
Abstract
This document specifies a Directional Airtime (DAT) link metric for
usage in Optimized Link State Routing version 2 (OLSRv2).
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for examination, experimental implementation, and
evaluation.
This document defines an Experimental Protocol for the Internet
community. This document is a product of the Internet Engineering
Task Force (IETF). It represents the consensus of the IETF
community. It has received public review and has been approved for
publication by the Internet Engineering Steering Group (IESG). Not
all documents approved by the IESG are a candidate for any level of
Internet Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7779.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Rogge & Baccelli Experimental [Page 1]
RFC 7779 Directional Airtime Metric OLSRv2 April 2016
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Applicability Statement . . . . . . . . . . . . . . . . . . . 4
4. Directional Airtime Metric Rationale . . . . . . . . . . . . 5
5. Metric Functioning and Overview . . . . . . . . . . . . . . . 6
6. Protocol Constants . . . . . . . . . . . . . . . . . . . . . 7
7. Protocol Parameters . . . . . . . . . . . . . . . . . . . . . 8
7.1. Recommended Values . . . . . . . . . . . . . . . . . . . 8
8. Data Structures . . . . . . . . . . . . . . . . . . . . . . . 8
8.1. Initial Values . . . . . . . . . . . . . . . . . . . . . 9
9. Packets and Messages . . . . . . . . . . . . . . . . . . . . 10
9.1. Definitions . . . . . . . . . . . . . . . . . . . . . . . 10
9.2. Requirements for Using DAT Metric in OLSRv2
Implementations . . . . . . . . . . . . . . . . . . . . . 10
9.3. Link-Loss Data Gathering . . . . . . . . . . . . . . . . 11
9.4. HELLO Message Processing . . . . . . . . . . . . . . . . 12
10. Timer Event Handling . . . . . . . . . . . . . . . . . . . . 12
10.1. Packet Timeout Processing . . . . . . . . . . . . . . . 12
10.2. Metric Update . . . . . . . . . . . . . . . . . . . . . 13
11. Security Considerations . . . . . . . . . . . . . . . . . . . 14
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
12.1. Normative References . . . . . . . . . . . . . . . . . . 14
12.2. Informative References . . . . . . . . . . . . . . . . . 15
Appendix A. Future Work . . . . . . . . . . . . . . . . . . . . 17
Appendix B. OLSR.org Metric History . . . . . . . . . . . . . . 17
Appendix C. Link-Speed Stabilization . . . . . . . . . . . . . . 18
Appendix D. Packet-Loss Hysteresis . . . . . . . . . . . . . . . 19
Appendix E. Example DAT Values . . . . . . . . . . . . . . . . . 19
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 20
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21
1. Introduction
One of the major shortcomings of Optimized Link State Routing (OLSR)
[RFC3626] is the lack of a granular link-cost metric between OLSR
routers. Operational experience with OLSR networks gathered since
its publication has revealed that wireless networks links can have
highly variable and heterogeneous properties. This makes a hop-count
metric insufficient for effective OLSR routing.
Based on this experience, OLSRv2 [RFC7181] integrates the concept of
link metrics directly into the core specification of the routing
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