OSPF Strict-Mode for BFD
draft-ietf-lsr-ospf-bfd-strict-mode-01
Link State Routing K. Talaulikar
Internet-Draft P. Psenak
Intended status: Standards Track Cisco Systems, Inc.
Expires: January 1, 2021 A. Fu
Bloomberg
M. Rajesh
Juniper Networks
June 30, 2020
OSPF Strict-Mode for BFD
draft-ietf-lsr-ospf-bfd-strict-mode-01
Abstract
This document specifies the extensions to OSPF that enable an OSPF
router to signal the requirement for a Bidirectional Forwarding
Detection (BFD) session prior to adjacency formation. Link-Local
Signaling (LLS) is used to advertise this requirement of "strict-
mode" of BFD session establishment for OSPF adjacency. If both OSPF
neighbors advertise the "strict-mode" of BFD, adjacency formation
will be blocked until a BFD session has been successfully
established.
Status of This Memo
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This Internet-Draft will expire on January 1, 2021.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. LLS B-bit Flag . . . . . . . . . . . . . . . . . . . . . . . 3
3. Local Interface IPv4 Address TLV . . . . . . . . . . . . . . 3
4. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. OSPFv3 IPv4 Address-Family Specifics . . . . . . . . . . 6
4.2. Graceful Restart Considerations . . . . . . . . . . . . . 6
5. Operations & Management Considerations . . . . . . . . . . . 6
6. Backward Compatibility . . . . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
8. Security Considerations . . . . . . . . . . . . . . . . . . . 8
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
10.1. Normative References . . . . . . . . . . . . . . . . . . 8
10.2. Informative References . . . . . . . . . . . . . . . . . 9
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
Bidirectional Forwarding Detection (BFD) [RFC5880] enables routers to
monitor dataplane connectivity and to detect faults in the
bidirectional path between them. BFD is leveraged by routing
protocols like OSPFv2[RFC2328] and OSPFv3 [RFC5340] to detect
connectivity failures for established adjacencies and trigger the
rerouting of traffic around the failure more quickly than with OSPF
hello packet monitoring.
The use of BFD for monitoring routing protocols adjacencies is
described in [RFC5882]. When BFD monitoring is enabled for OSPF
adjacencies, the BFD session is bootstrapped based on the neighbor
address information discovered by the exchange of OSPF hello packets.
Faults in the bidirectional forwarding detected via BFD then result
in the OSPF adjacency being brought down. Note that it is possible
in some failure scenarios for the network to be in a state such that
an OSPF adjacency can be established but a BFD session cannot be
established and maintained. In certain other scenarios, a degraded
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