MPLS Working Group Kamran Raza
Internet Draft Sami Boutros
Updates: 5036, 4447, 5918, 6388, 3212 Luca Martini
Intended status: Standards Track Cisco Systems, Inc.
Expires: July 19, 2014
Nicolai Leymann
Deutsche Telekom
January 20, 2014
Label Advertisement Discipline for LDP FECs
draft-ietf-mpls-ldp-applicability-label-adv-02.txt
Abstract
The label advertising behavior of an LDP speaker for a given FEC is
governed by the FEC type and not necessarily by the LDP session's
negotiated label advertisement mode. This document updates RFC 5036
to make that fact clear, as well as updates RFC 3212, RFC 4447,
RFC 5918, and RFC 6388 by specifying the label advertisement mode
for all currently defined FECs.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on July 19, 2014.
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Copyright Notice
Copyright (c) 2014 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
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Table of Contents
1. Introduction 2
2. Label Advertisement Discipline 3
2.1. Update to RFC-5036 3
2.2. Specification for LDP FECs 4
3. Security Considerations 4
4. IANA Considerations 4
5. References 5
5.1. Normative References 5
5.2. Informative References 5
6. Acknowledgments 5
1. Introduction
Label Distribution Protocol (LDP) [RFC5036] allows label
advertisement mode negotiation at the time of session establishment.
LDP specification also dictates that only single label advertisement
mode is negotiated, agreed and used for a given LDP session between
two LSRs.
The negotiated label advertisement mode defined in RFC 5036 and
carried in the LDP Initialization message is only indicative. It
indicates how the LDP speakers on a session will advertise labels for
some FECs, but it is not a rule that restricts the speakers to behave
in a specific way. Furthermore, for some FEC types the advertising
behavior of the LDP speaker is governed by the FEC type and not by
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the negotiated behavior.
This document updates [RFC5036] to make that fact clear, and updates
[RFC3212], [RFC4447], [RFC5036], [RFC5918], and [RFC6388] to indicate
for each FEC type that has already been defined whether the label
binding advertisements for the FEC are constrained by the negotiated
label advertisement mode or not. Furthermore, this document specifies
the label advertisement mode to be used for all currently defined
LDP FECs.
2. Label Advertisement Discipline
To remove any ambiguity and conflict regarding label advertisement
discipline amongst different FEC types sharing a common LDP session,
this document specifies a label advertisement disciplines for FEC
types.
This document introduces following types for specifying a label
advertisement discipline for a FEC type:
- DU (Downstream Unsolicited)
- DoD (Downstream On Demand)
- As negotiated (DU or DoD)
- Upstream ([RFC6389])
- Not Applicable
2.1. Update to RFC-5036
The section 3.5.3 of [RFC5036] is updated to add following two
statements under the description of "A, Label Advertisement
Discipline":
- Each document defining an LDP FEC must state the applicability
of the negotiated label advertisement discipline for label
binding advertisements for that FEC. If the negotiated label
advertisement discipline does not apply to the FEC, the
document must also explicitly state the discipline to be used
for the FEC.
- This document defines the label advertisement discipline for
the following FEC types:
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+----------+----------+--------------------------------+
| FEC Type | FEC Name | Label advertisement discipline |
+----------+----------+--------------------------------+
| 0x01 | Wildcard | Not applicable |
| 0x02 | Prefix | As negotiated (DU or DoD) |
+----------+----------+--------------------------------+
2.2. Specification for LDP FECs
Following is the specification of label advertisement disciplines to
be used for currently defined LDP FEC types.
+------+----------------+--------------------------------+------+
| FEC | FEC Name | Label advertisement discipline |RFC |
| Type | | | |
+------+----------------+--------------------------------+------+
| 0x01 | Wildcard | Not applicable | 5036 |
| 0x02 | Prefix | As negotiated (DU or DoD) | 5036 |
| 0x04 | CR-LSP | DoD | 3212 |
| 0x05 | Typed Wildcard | Not applicable | 5918 |
| 0x06 | P2MP | DU | 6388 |
| 0x07 | MP2MP-up | DU | 6388 |
| 0x08 | MP2MP-down | DU | 6388 |
| 0x80 | PWid | DU | 4447 |
| 0x81 | Gen. PWid | DU | 4447 |
+------+----------------+--------------------------------+------+
The above table also lists the RFC (in which given FEC type is
defined), and hence this document updates all the above listed RFCs.
3. Security Considerations
This document specification only clarifies the applicability of LDP
session's label advertisement mode, and hence does not add any LDP
security mechanics and considerations to those already defined in
the LDP specification [RFC5036].
4. IANA Considerations
This document mandates the specification of a label advertisement
discipline for each defined FEC type, and hence extends IANA's
"Forwarding Equivalence Class (FEC) Type Name Space" registry under
IANA's "Label Distribution Protocol (LDP) Parameters" as follows:
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- Add a new column titled "Label advertisement discipline" with
following possible values:
o DU
o DoD
o As negotiated (DU or DoD)
o Upstream
o Not applicable
- For the existing FEC types, populate this column with the
values listed under section 2.2.
5. References
5.1. Normative References
[RFC5036] L. Andersson, I. Minei, and B. Thomas, "LDP
Specification", RFC 5036, September 2007.
[RFC3212] B. Jamoussi, et al., "Constraint-Based LSP Setup using
LDP", RFC 3212, January 2002
[RFC4447] L. Martini, Editor, E. Rosen, El-Aawar, T. Smith, G.
Heron, "Pseudowire Setup and Maintenance using the Label
Distribution Protocol", RFC 4447, April 2006.
[RFC5918] R. Asati, I. Minei, and B. Thomas, "Label Distribution
Protocol Typed Wildcard FEC", RFC 5918, August 2010.
[RFC6388] I. Minei, I. Wijnands, K. Kompella, and B. Thomas, "LDP
Extensions for P2MP and MP2MP LSPs", RFC 6388, November
2011.
[RFC6389] R. Aggarwal, and JL. Le Roux, "MPLS Upstream Label
Assignment for LDP", RFC 6389, November 2011.
5.2. Informative References
None.
6. Acknowledgments
We acknowledge Eric Rosen and Rajiv Asati for their initial review
and input on the document.
This document was prepared using 2-Word-v2.0.template.dot.
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Authors' Addresses
Kamran Raza
Cisco Systems, Inc.
2000 Innovation Drive,
Ottawa, ON K2K-3E8, Canada.
E-mail: skraza@cisco.com
Sami Boutros
Cisco Systems, Inc.
3750 Cisco Way,
San Jose, CA 95134, USA.
E-mail: sboutros@cisco.com
Luca Martini
Cisco Systems, Inc.
9155 East Nichols Avenue, Suite 400,
Englewood, CO 80112, USA.
E-mail: lmartini@cisco.com
Nicolai Leymann
Deutsche Telekom AG,
Winterfeldtstrasse 21,
Berlin 10781, Germany.
E-mail: N.Leymann@telekom.de
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