OSPF Strict-Mode for BFD
draft-ietf-lsr-ospf-bfd-strict-mode-02
Link State Routing K. Talaulikar
Internet-Draft P. Psenak
Intended status: Standards Track Cisco Systems, Inc.
Expires: July 3, 2021 A. Fu
Bloomberg
M. Rajesh
Juniper Networks
December 30, 2020
OSPF Strict-Mode for BFD
draft-ietf-lsr-ospf-bfd-strict-mode-02
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
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 3, 2021.
Copyright Notice
Copyright (c) 2020 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
Talaulikar, et al. Expires July 3, 2021 [Page 1]
Internet-Draft OSPF Strict-Mode for BFD December 2020
(https://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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. LLS B-bit Flag . . . . . . . . . . . . . . . . . . . . . . . 3
3. Local Interface IPv4 Address TLV . . . . . . . . . . . . . . 4
4. Procedures . . . . . . . . . . . . . . . . . . . . . . . . . 4
4.1. OSPFv3 IPv4 Address-Family Specifics . . . . . . . . . . 6
4.2. Graceful Restart Considerations . . . . . . . . . . . . . 6
5. Operations & Management Considerations . . . . . . . . . . . 7
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
Show full document text