OSPF Reverse Metric
draft-ietf-lsr-ospf-reverse-metric-00
Link State Routing K. Talaulikar
Internet-Draft P. Psenak
Intended status: Standards Track Cisco Systems, Inc.
Expires: July 9, 2020 H. Johnston
AT&T Labs
January 6, 2020
OSPF Reverse Metric
draft-ietf-lsr-ospf-reverse-metric-00
Abstract
This document specifies the extensions to OSPF that enables a router
to signal to its neighbor the metric that the neighbor should use
towards itself using link-local advertisement between them. The
signalling of this reverse metric, to be used on link(s) towards
itself, allows a router to influence the amount of traffic flowing
towards itself and in certain use-cases enables routers to maintain
symmetric metric on both sides of a link between them.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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 https://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 July 9, 2020.
Talaulikar, et al. Expires July 9, 2020 [Page 1]
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Copyright Notice
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document authors. All rights reserved.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Symmetrical Metric Based on Reference Bandwidth . . . . . 3
2.2. Adaptive Metric Signaling . . . . . . . . . . . . . . . . 4
3. Solution . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. LLS Reverse Metric TLV . . . . . . . . . . . . . . . . . . . 6
5. LLS Reverse TE Metric TLV . . . . . . . . . . . . . . . . . . 6
6. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 7
7. Backward Compatibility . . . . . . . . . . . . . . . . . . . 9
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
9. Security Considerations . . . . . . . . . . . . . . . . . . . 9
10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 10
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
12.1. Normative References . . . . . . . . . . . . . . . . . . 10
12.2. Informative References . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
Routers running the Open Shortest Path First (OSPFv2) [RFC2328] and
OSPFv3 [RFC5340] routing protocols originate a Router-LSA (Link State
Advertisement) that describes all its links to its neighbors and
includes a metric which indicates its "cost" of reaching the neighbor
over that link. Consider two routers R1 and R2 that are connected
via a link. The metric for this link in direction R1->R2 is
configured on R1 and in the direction R2->R1 is configured on R2.
Thus the configuration on R1 influences the traffic that it forwards
towards R2 but does not influence the traffic that it may receive
from R2 on that same link.
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