Clarifying Use of LSP Ping to Bootstrap BFD over MPLS LSP
draft-mirsky-mpls-bfd-bootstrap-clarify-01
| The information below is for an old version of the document |
| Document |
Type |
|
Active Internet-Draft (individual)
|
|
Authors |
|
Greg Mirsky
,
Yanhua Zhao
,
Gyan Mishra
|
|
Last updated |
|
2020-12-08
|
|
Stream |
|
(None)
|
|
Formats |
|
pdf
htmlized (tools)
htmlized
bibtex
|
| Stream |
Stream state |
|
(No stream defined) |
|
Consensus Boilerplate |
|
Unknown
|
|
RFC Editor Note |
|
(None)
|
| IESG |
IESG state |
|
I-D Exists
|
|
Telechat date |
|
|
|
Responsible AD |
|
(None)
|
|
Send notices to |
|
(None)
|
MPLS Working Group G. Mirsky
Internet-Draft Y. Zhao
Updates: 5884 (if approved) ZTE Corporation
Intended status: Standards Track G. Mishra
Expires: June 11, 2021 Verizon Inc.
December 8, 2020
Clarifying Use of LSP Ping to Bootstrap BFD over MPLS LSP
draft-mirsky-mpls-bfd-bootstrap-clarify-01
Abstract
This document, if approved, updates RFC 5884 by clarifying procedures
for using MPLS LSP ping to bootstrap Bidirectional Forwarding
Detection (BFD) over MPLS Label Switch Path.
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 June 11, 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
(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.
Mirsky, et al. Expires June 11, 2021 [Page 1]
Internet-Draft Clarify Bootstrapping BFD over MPLS LSP December 2020
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 2
3. Use of Return Mode Field . . . . . . . . . . . . . . . . . . 2
4. Use of BFD Discriminator TLV in LSP Echo Reply . . . . . . . 3
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
6. Security Considerations . . . . . . . . . . . . . . . . . . . 3
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3
8. Normative References . . . . . . . . . . . . . . . . . . . . 3
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
[RFC5884] defines how LSP Ping [RFC8029] uses BFD Discriminator TLV
to bootstrap Bidirectional Forwarding Detection (BFD) session over
MPLS Label Switch Path (LSP). Implementation and operational
experiences suggest that two aspects of using LSP ping to bootstrap
BFD session can benefit from clarification. This document updates
[RFC5884] in use of Return mode field in MPLS LSP echo request
message and use of BFD Discriminator TLV in MPLS LSP echo reply.
2. 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.
3. Use of Return Mode Field
[RFC5884] does not define the value to be used for the Return mode
field [RFC8029] when LSP ping is used to bootstrap a BFD session of
MPLS LSP. When LSP echo request is being used to detect defects in
MPLS data plane and verify consistency between the control plane and
the data plane echo reply is needed to confirm the correct state,
provide positive acknowledgment. But when an LSP echo request is
being used to bootstrap BFD session, then the positive
acknowledgment, according to [RFC5884] is provided by the egress
transmitting BFD control message. Thus LSP echo reply is not
required to bootstrap BFD session and hence the Return mode field in
echo request message SHOULD be set to 1 (Do not reply) [RFC8029] when
LSP echo request used to bootstrap BFD session.
Mirsky, et al. Expires June 11, 2021 [Page 2]
Internet-Draft Clarify Bootstrapping BFD over MPLS LSP December 2020
4. Use of BFD Discriminator TLV in LSP Echo Reply
[RFC5884] in section 6 defines that echo reply by the egress LSR to
BFD bootstrapping echo request MAY include BFD Discriminator TLV with
locally assigned discriminator value for the BFD session. But the
[RFC5884] does not define how the ingress LSR may use the returned
value. From a practical point, as discussed in Section 3, the
returned value is not useful since the egress is required to send the
BFD control message right after successfully validating the FEC and
before sending an echo reply message. Secondly, identifying the
corresponding BFD session at ingress without returning its
discriminator presents an unnecessary challenge for the
implementation. Thus the egress LSR SHOULD NOT include BFD
Discriminator TLV if sending echo reply to BFD bootstrapping echo
request.
5. IANA Considerations
This document does not require any action by IANA. This section may
be removed.
6. Security Considerations
This document does not introduce new security aspects but inherits
all security considerations from [RFC5880], [RFC5884], [RFC8029].
7. Acknowledgements
TBA
8. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
<https://www.rfc-editor.org/info/rfc5880>.
[RFC5884] Aggarwal, R., Kompella, K., Nadeau, T., and G. Swallow,
"Bidirectional Forwarding Detection (BFD) for MPLS Label
Switched Paths (LSPs)", RFC 5884, DOI 10.17487/RFC5884,
June 2010, <https://www.rfc-editor.org/info/rfc5884>.
Mirsky, et al. Expires June 11, 2021 [Page 3]
Internet-Draft Clarify Bootstrapping BFD over MPLS LSP December 2020
[RFC8029] Kompella, K., Swallow, G., Pignataro, C., Ed., Kumar, N.,
Aldrin, S., and M. Chen, "Detecting Multiprotocol Label
Switched (MPLS) Data-Plane Failures", RFC 8029,
DOI 10.17487/RFC8029, March 2017,
<https://www.rfc-editor.org/info/rfc8029>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
Authors' Addresses
Greg Mirsky
ZTE Corporation
Email: gregimirsky@gmail.com
Yanhua Zhao
ZTE Corporation
Email: zhao.yanhua3@zte.com.cn
Gyan Mishra
Verizon Inc.
Email: gyan.s.mishra@verizon.com
Mirsky, et al. Expires June 11, 2021 [Page 4]