OSPF Graceful Link Shutdown
RFC 8379
Internet Engineering Task Force (IETF) S. Hegde
Request for Comments: 8379 Juniper Networks, Inc.
Category: Standards Track P. Sarkar
ISSN: 2070-1721 Arrcus, Inc.
H. Gredler
RtBrick Inc.
M. Nanduri
ebay Corporation
L. Jalil
Verizon
May 2018
OSPF Graceful Link Shutdown
Abstract
When a link is being prepared to be taken out of service, the traffic
needs to be diverted from both ends of the link. Increasing the
metric to the highest value on one side of the link is not sufficient
to divert the traffic flowing in the other direction.
It is useful for the routers in an OSPFv2 or OSPFv3 routing domain to
be able to advertise a link as being in a graceful-shutdown state to
indicate impending maintenance activity on the link. This
information can be used by the network devices to reroute the traffic
effectively.
This document describes the protocol extensions to disseminate
graceful-link-shutdown information in OSPFv2 and OSPFv3.
Status of This Memo
This is an Internet Standards Track document.
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). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8379.
Hegde, et al. Standards Track [Page 1]
RFC 8379 OSPF Graceful Link Shutdown May 2018
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Flooding Scope . . . . . . . . . . . . . . . . . . . . . . . 4
4. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 4
4.1. OSPFv2 Graceful-Link-Shutdown Sub-TLV . . . . . . . . . . 4
4.2. Remote IPv4 Address Sub-TLV . . . . . . . . . . . . . . . 4
4.3. Local/Remote Interface ID Sub-TLV . . . . . . . . . . . . 5
4.4. OSPFv3 Graceful-Link-Shutdown Sub-TLV . . . . . . . . . . 6
4.5. BGP-LS Graceful-Link-Shutdown TLV . . . . . . . . . . . . 6
4.6. Distinguishing Parallel Links . . . . . . . . . . . . . . 7
5. Elements of Procedure . . . . . . . . . . . . . . . . . . . . 8
5.1. Point-to-Point Links . . . . . . . . . . . . . . . . . . 8
5.2. Broadcast/NBMA Links . . . . . . . . . . . . . . . . . . 9
5.3. Point-to-Multipoint Links . . . . . . . . . . . . . . . . 10
5.4. Unnumbered Interfaces . . . . . . . . . . . . . . . . . . 10
5.5. Hybrid Broadcast and P2MP Interfaces . . . . . . . . . . 10
6. Backward Compatibility . . . . . . . . . . . . . . . . . . . 10
7. Applications . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1. Overlay Network . . . . . . . . . . . . . . . . . . . . . 11
7.2. Controller-Based Deployments . . . . . . . . . . . . . . 12
7.3. L3VPN Services and Sham Links . . . . . . . . . . . . . . 13
7.4. Hub and Spoke Deployment . . . . . . . . . . . . . . . . 13
8. Security Considerations . . . . . . . . . . . . . . . . . . . 13
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
10.1. Normative References . . . . . . . . . . . . . . . . . . 14
10.2. Informative References . . . . . . . . . . . . . . . . . 16
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