Internet DRAFT - draft-ietf-isis-sbfd-discriminator
draft-ietf-isis-sbfd-discriminator
Networking Working Group L. Ginsberg
Internet-Draft N. Akiya
Intended status: Standards Track Cisco Systems
Expires: September 3, 2015 M. Chen
Huawei
March 2, 2015
Advertising S-BFD Discriminators in IS-IS
draft-ietf-isis-sbfd-discriminator-02.txt
Abstract
This document defines a means of advertising one or more S-BFD
Discriminators using the IS-IS Router Capability TLV.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
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
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This Internet-Draft will expire on September 3, 2015.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Encoding Format . . . . . . . . . . . . . . . . . . . . . . 2
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . 3
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
6. Normative References . . . . . . . . . . . . . . . . . . . . 4
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4
1. Introduction
[S-BFD] defines a simplified mechanism to use Bidirectional
Forwarding Detection (BFD)[RFC5880]. This mechanism depends on
network nodes knowing the BFD discriminators which each node in the
network has reserved for this purpose. Use of the Intermediate
System to Intermediate System (IS-IS)[IS-IS] protocol is one possible
means of advertising these discriminators.
2. Encoding Format
The IS-IS Router CAPABILITY TLV as defined in [RFC4971] will be used
to advertise S-BFD discriminators. A new sub-TLV is defined as
described below. S-BFD Discriminators sub-TLVs are formatted as
specified in [RFC5305].
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No. of octets
+-----------------------------+
| Type (to be assigned by | 1
| IANA - suggested value 20) |
+-----------------------------+
| Length (multiple of 4) | 1
+-----------------------------+
| Discriminator Value(s) | 4/Discriminator
: :
+-----------------------------+
Inclusion of the S-BFD Discriminators sub-TLV in a Router Capability
TLV is optional. Multiple S-BFD Discriminators sub-TLVs MAY be
advertised by an IS. When multiple S-BFD discriminators are
advertised how a given discriminator is mapped to a specific use case
is out of scope for this document.
S-BFD discriminator advertisements MAY be flooded within an area or
throughout the domain using the procedures specified in [RFC4971].
The appropriate flooding scope depends on the intended use of S-BFD.
If S-BFD use will be exclusively within a Level-1 area then area
scope is appropriate. If S-BFD usage will span different L1 areas
then domain scope is appropriate.
3. IANA Considerations
This document requires the definition of a new sub-TLV in the Sub-
TLVs for TLV 242 registry. The value written below is a suggested
value subject to assignment by IANA.
Value Description
---- ---------------------
20 S-BFD Discriminators
4. Security Considerations
Security concerns for IS-IS are addressed in [IS-IS], [RFC5304], and
[RFC5310]. Introduction of the S-BFD Discriminators sub-TLV
introduces no new security risks for IS-IS.
Advertisement of the S-BFD discriminators does make it possible for
attackers to initiate S-BFD sessions using the advertised
information. The vulnerabilities this poses and how to mitigate them
are discussed in the Security Considerations section of [S-BFD].
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5. Acknowledgements
The authors wish to thank Sam Aldrin, Manav Bhatia, and Carlos
Pignataro for input essential to defining the needed functionality.
6. Normative References
[IS-IS] "Intermediate system to Intermediate system intra-domain
routeing information exchange protocol for use in
conjunction with the protocol for providing the
connectionless-mode Network Service (ISO 8473), ISO/IEC
10589:2002, Second Edition.", Nov 2002.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4971] Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate
System to Intermediate System (IS-IS) Extensions for
Advertising Router Information", RFC 4971, July 2007.
[RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
Authentication", RFC 5304, October 2008.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, October 2008.
[RFC5310] Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
and M. Fanto, "IS-IS Generic Cryptographic
Authentication", RFC 5310, February 2009.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, June 2010.
[S-BFD] "Seamless Bidirectional Forwarding Detection (S-BFD),
draft-ietf-bfd-seamless-base-04(work in progress)",
January 2015.
Authors' Addresses
Les Ginsberg
Cisco Systems
510 McCarthy Blvd.
Milpitas, CA 95035
USA
Email: ginsberg@cisco.com
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Nobo Akiya
Cisco Systems
Email: nobo@cisco.com
Mach(Guoyi) Chen
Huawei
Email: mach.chen@huawei.com
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