One document matched: draft-ietf-l2tpext-sbfd-discriminator-02.txt
Differences from draft-ietf-l2tpext-sbfd-discriminator-01.txt
Networking Working Group V. Govindan
Internet-Draft C. Pignataro
Intended status: Standards Track Cisco
Expires: July 6, 2016 January 3, 2016
Advertising S-BFD Discriminators in L2TPv3
draft-ietf-l2tpext-sbfd-discriminator-02.txt
Abstract
This document defines a new AVP that allows L2TP Control Connection
Endpoints (LCCEs) to advertise one or more Seamless BFD (S-BFD)
Discriminator values using L2TPv3.
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
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://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 6, 2016.
Copyright Notice
Copyright (c) 2016 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
(http://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
Govindan & Pignataro Expires July 6, 2016 [Page 1]
Internet-Draft S-BFD Disc in L2TPv3 January 2016
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. Terminology . . . . . . . . . . . . . . . . . . . . . . . 2
2. S-BFD Target Discriminator ID AVP . . . . . . . . . . . . . . 2
2.1. Encoding Format . . . . . . . . . . . . . . . . . . . . . 3
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4
4. Security Considerations . . . . . . . . . . . . . . . . . . . 4
5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4
6. Contributing Authors . . . . . . . . . . . . . . . . . . . . 4
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Normative References . . . . . . . . . . . . . . . . . . 5
7.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5
1. Introduction
[I-D.ietf-bfd-seamless-base] defines a simplified mechanism to use
Bidirectional Forwarding Detection (BFD) [RFC5880], referred to as
Seamless Bidirectional Forwarding Detection (S-BFD). The S-BFD
mechanisms depend on network nodes knowing the BFD discriminators
which each node in the network has reserved for this purpose. S-BFD
requires the usage of unique discriminators within an administrative
domain. The use of Layer Two Tunneling Protocol - Version 3 (L2TPv3)
[RFC3931] is one possible means of advertising these discriminators.
This document specifies the encoding to be used when S-BFD
discriminators are advertised using L2TPv3.
1.1. Terminology
The reader is expected to be very familiar with the terminology and
protocol constructs defined in S-BFD (see Section 2 of
[I-D.ietf-bfd-seamless-base]) and L2TPv3 (see Section 1.3 of
[RFC3931]).
2. S-BFD Target Discriminator ID AVP
The "S-BFD Target Discriminator ID" AVP is exchanged using the ICRQ,
ICRP, OCRQ, and OCRP control messages during session negotiations.
Govindan & Pignataro Expires July 6, 2016 [Page 2]
Internet-Draft S-BFD Disc in L2TPv3 January 2016
2.1. Encoding Format
The S-BFD Target Discriminator ID AVP, Attribute Type "TBA by IANA",
is an identifier used to advertise the S-BFD Target Discriminator(s)
supported by an LCCE for the S-BFD Reflector operation. This AVP
indicates that the advertiser implements an S-BFD reflector
supporting the specified target discriminator(s) and is ready for
S-BFD Reflector operation. The receiving LCCE MAY use this AVP if it
wants to monitor connectivity to the advertising LCCE using S-BFD.
The Attribute Value field for this AVP has the following format:
S-BFD Target Discriminator ID (ICRQ, ICRP, OCRQ, OCRP):
No. of octets
+-----------------------------+
| Discriminator Value(s) | 4/Discriminator
: :
+-----------------------------+
An LCCE MAY include the S-BFD Discriminator Advertisement AVP in a
L2TP Control Protocol message (ICRQ, ICRP, OCRQ, OCRP) [RFC3931].
Multiple S-BFD Discriminators AVPs MAY be advertised by a LCCE. If
the other LCCE does not wish to monitor connectivity using S-BFD, it
MAY safely discard this AVP without affecting the rest of session
negotiation. While current use-cases
[I-D.ietf-bfd-seamless-use-case] of S-BFD require advertisement of
only one discriminator, the AVP encoding allows specification an
arbitrary number of discrminators (at least one) for extensibility.
When multiple S-BFD discriminators are advertised, the mechanism to
choose a subset of specific discriminator(s) is out of scope for this
document.
The S-BFD Target Discriminator ID AVP allows for advertising at least
one S-BFD Discriminator value:
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Discriminator 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Discriminator 2 (Optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Discriminator n (Optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Govindan & Pignataro Expires July 6, 2016 [Page 3]
Internet-Draft S-BFD Disc in L2TPv3 January 2016
The M bit of the L2TP Control Protocol Message (ICRQ, ICRP, OCRQ,
OCRP) [RFC3931] MUST NOT be set inside the S-BFD Target Discriminator
ID AVP advertisement.
3. IANA Considerations
IANA maintains a sub-registry "Message Type AVP (Attribute Type 0)
Values" in the "Control Message Attribute Value Pairs" as per
[RFC3438]. IANA is requested to assign the first free value from
this sub-registry as the Message typ AVP for "S-BFD Target
Discriminator ID".
A summary of the new AVPs requested for Attribute Type 0 follows:
Control Message Attribute Value Pairs
Attribute
Type Description
----------- ------------------
TBA by IANA S-BFD Target Discriminator ID
4. Security Considerations
Security concerns for L2TP are addressed in [RFC3931]. Introduction
of the S-BFD Discriminator Advertisement AVP introduces no new
security risks for L2TP.
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
[I-D.ietf-bfd-seamless-base].
5. Acknowledgements
Authors would like to thank Nobo Akiya, Stewart Bryant and Pawel
Sowinski for providing core inputs for the document and for
performing thorough reviews and providing number of comments.
Authors would like to thank Nagendra Kumar for his reviews.
6. Contributing Authors
Mallik Mudigonda
Cisco Systems
Email: mmudigon@cisco.com
Govindan & Pignataro Expires July 6, 2016 [Page 4]
Internet-Draft S-BFD Disc in L2TPv3 January 2016
7. References
7.1. Normative References
[I-D.ietf-bfd-seamless-base]
Akiya, N., Pignataro, C., Ward, D., Bhatia, M., and J.
Networks, "Seamless Bidirectional Forwarding Detection
(S-BFD)", draft-ietf-bfd-seamless-base-05 (work in
progress), June 2015.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3438] Townsley, W., "Layer Two Tunneling Protocol (L2TP)
Internet Assigned Numbers Authority (IANA) Considerations
Update", BCP 68, RFC 3438, DOI 10.17487/RFC3438, December
2002, <http://www.rfc-editor.org/info/rfc3438>.
[RFC3931] Lau, J., Ed., Townsley, M., Ed., and I. Goyret, Ed.,
"Layer Two Tunneling Protocol - Version 3 (L2TPv3)",
RFC 3931, DOI 10.17487/RFC3931, March 2005,
<http://www.rfc-editor.org/info/rfc3931>.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
<http://www.rfc-editor.org/info/rfc5880>.
7.2. Informative References
[I-D.ietf-bfd-seamless-use-case]
Aldrin, S., Bhatia, M., Matsushima, S., Mirsky, G., and N.
Kumar, "Seamless Bidirectional Forwarding Detection (BFD)
Use Case", draft-ietf-bfd-seamless-use-case-03 (work in
progress), July 2015.
Authors' Addresses
Vengada Prasad Govindan
Cisco Systems, Inc.
Email: venggovi@cisco.com
Govindan & Pignataro Expires July 6, 2016 [Page 5]
Internet-Draft S-BFD Disc in L2TPv3 January 2016
Carlos Pignataro
Cisco Systems, Inc.
Email: cpignata@cisco.com
Govindan & Pignataro Expires July 6, 2016 [Page 6]
| PAFTECH AB 2003-2026 | 2026-04-23 13:06:16 |