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<pre>Internet Engineering Task Force (IETF) K. Raza
Request for Comments: 7358 S. Boutros
Updates: <a href="./rfc3212">3212</a>, <a href="./rfc4447">4447</a>, <a href="./rfc5036">5036</a>, <a href="./rfc5918">5918</a>, <a href="./rfc6388">6388</a>, <a href="./rfc7140">7140</a> L. Martini
Category: Standards Track Cisco Systems, Inc.
ISSN: 2070-1721 N. Leymann
Deutsche Telekom
October 2014
<span class="h1">Label Advertisement Discipline</span>
<span class="h1">for LDP Forwarding Equivalence Classes (FECs)</span>
Abstract
The label advertising behavior of an LDP speaker for a given
Forwarding Equivalence Class (FEC) is governed by the FEC type and
not necessarily by the LDP session's negotiated label advertisement
mode. This document updates <a href="./rfc5036">RFC 5036</a> to make that fact clear. It
also updates RFCs 3212, 4447, 5918, 6388, and 7140 by specifying the
label advertisement mode for all currently defined LDP FEC types.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in <a href="./rfc5741#section-2">Section 2 of RFC 5741</a>.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
<a href="http://www.rfc-editor.org/info/rfc7358">http://www.rfc-editor.org/info/rfc7358</a>.
<span class="grey">Raza, et al. Standards Track [Page 1]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-2" ></span>
<span class="grey"><a href="./rfc7358">RFC 7358</a> Label Advert. Discipline for LDP FECs October 2014</span>
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to <a href="https://www.rfc-editor.org/bcp/bcp78">BCP 78</a> and the IETF Trust's Legal
Provisions Relating to IETF Documents
(<a href="http://trustee.ietf.org/license-info">http://trustee.ietf.org/license-info</a>) 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
<a href="#section-1">1</a>. Introduction ....................................................<a href="#page-2">2</a>
<a href="#section-2">2</a>. Label Advertisement Discipline ..................................<a href="#page-3">3</a>
<a href="#section-2.1">2.1</a>. Update to <a href="./rfc5036">RFC 5036</a> .........................................<a href="#page-3">3</a>
<a href="#section-2.2">2.2</a>. Specification for LDP FECs .................................<a href="#page-4">4</a>
<a href="#section-3">3</a>. Security Considerations .........................................<a href="#page-4">4</a>
<a href="#section-4">4</a>. IANA Considerations .............................................<a href="#page-4">4</a>
<a href="#section-5">5</a>. References ......................................................<a href="#page-6">6</a>
<a href="#section-5.1">5.1</a>. Normative References .......................................<a href="#page-6">6</a>
<a href="#section-5.2">5.2</a>. Informative References .....................................<a href="#page-7">7</a>
Acknowledgments ....................................................<a href="#page-8">8</a>
Authors' Addresses .................................................<a href="#page-8">8</a>
<span class="h2"><a class="selflink" id="section-1" href="#section-1">1</a>. Introduction</span>
The Label Distribution Protocol (LDP) [<a href="./rfc5036" title=""LDP Specification"">RFC5036</a>] allows label
advertisement mode negotiation at the time of session establishment.
The LDP specification also dictates that only a single label
advertisement mode be negotiated, agreed upon, and used for a given
LDP session between two Label Switching Routers (LSRs).
The negotiated label advertisement mode defined in <a href="./rfc5036">RFC 5036</a> and
carried in the LDP Initialization message is only indicative. It
indicates how the LDP speakers on a session will advertise labels for
some Forwarding Equivalence Classes (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 the negotiated behavior.
This document updates [<a href="./rfc5036" title=""LDP Specification"">RFC5036</a>] to make that fact clear. It also
updates [<a href="./rfc3212" title=""Constraint-Based LSP Setup using LDP"">RFC3212</a>], [<a href="./rfc4447" title=""Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)"">RFC4447</a>], [<a href="./rfc5918" title=""Label Distribution Protocol (LDP) 'Typed Wildcard' Forward Equivalence Class (FEC)"">RFC5918</a>], [<a href="./rfc6388" title=""Label Distribution Protocol Extensions for Point-to-Multipoint and Multipoint-to-Multipoint Label Switched Paths"">RFC6388</a>], and [<a href="./rfc7140" title=""LDP Extensions for Hub and Spoke Multipoint Label Switched Path"">RFC7140</a>] to
indicate, for each FEC type that has already been defined, whether
<span class="grey">Raza, et al. Standards Track [Page 2]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-3" ></span>
<span class="grey"><a href="./rfc7358">RFC 7358</a> Label Advert. Discipline for LDP FECs October 2014</span>
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 FECs.
<span class="h2"><a class="selflink" id="section-2" href="#section-2">2</a>. Label Advertisement Discipline</span>
To remove any ambiguity and conflict regarding a label advertisement
discipline among different FEC types sharing a common LDP session,
this document specifies a label advertisement discipline for FEC
types.
This document introduces the 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 ([<a href="./rfc6389" title=""MPLS Upstream Label Assignment for LDP"">RFC6389</a>])
- Not applicable
- Unknown
<span class="h3"><a class="selflink" id="section-2.1" href="#section-2.1">2.1</a>. Update to <a href="./rfc5036">RFC 5036</a></span>
<a href="./rfc5036#section-3.5.3">Section 3.5.3 of [RFC5036]</a> is updated to add the 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:
+----------+----------+--------------------------------+
| FEC Type | FEC Name | Label Advertisement Discipline |
+----------+----------+--------------------------------+
| 0x01 | Wildcard | Not applicable |
| 0x02 | Prefix | As negotiated (DU or DoD) |
+----------+----------+--------------------------------+
<span class="grey">Raza, et al. Standards Track [Page 3]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-4" ></span>
<span class="grey"><a href="./rfc7358">RFC 7358</a> Label Advert. Discipline for LDP FECs October 2014</span>
<span class="h3"><a class="selflink" id="section-2.2" href="#section-2.2">2.2</a>. Specification for LDP FECs</span>
The label advertisement discipline for currently defined LDP FEC
types is listed in <a href="#section-4">Section 4</a>.
This document updates the respective RFCs in which these FECs are
introduced and defined.
<span class="h2"><a class="selflink" id="section-3" href="#section-3">3</a>. Security Considerations</span>
This document only clarifies the applicability of an 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 [<a href="./rfc5036" title=""LDP Specification"">RFC5036</a>].
<span class="h2"><a class="selflink" id="section-4" href="#section-4">4</a>. IANA Considerations</span>
This document mandates the specification of a label advertisement
discipline for each defined FEC type and hence IANA's "Forwarding
Equivalence Class (FEC) Type Name Space" registry under IANA's "Label
Distribution Protocol (LDP) Parameters" registry has been extended as
follows:
- Added a new column titled "Label Advertisement Discipline" with
the following possible values:
o DU
o DoD
o As negotiated (DU or DoD)
o Upstream
o Not applicable
o Unknown
- Made this document an additional reference for the registry itself
and for all affected registrations.
- Kept other columns of the registry in place and populated as they
were.
<span class="grey">Raza, et al. Standards Track [Page 4]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-5" ></span>
<span class="grey"><a href="./rfc7358">RFC 7358</a> Label Advert. Discipline for LDP FECs October 2014</span>
For the currently assigned FEC types, the updated registry looks
like:
+=====+====+===============+==============+===========+============+
|Value|Hex | Name |Label | Reference |Notes/ |
| | | |Advertisement | |Registration|
| | | |Discipline | |Date |
+=====+====+===============+==============+===========+============+
| 0 |0x00|Reserved | | | |
+-----+----+---------------+--------------+-----------+------------+
| 1 |0x01|Wildcard |Not applicable| [<a href="./rfc5036" title=""LDP Specification"">RFC5036</a>] | |
| | | | | [<a href="./rfc7358">RFC7358</a>] | |
+-----+----+---------------+--------------+-----------+------------+
| 2 |0x02|Prefix |As negotiated | [<a href="./rfc5036" title=""LDP Specification"">RFC5036</a>] | |
| | | |(DU or DoD) | [<a href="./rfc7358">RFC7358</a>] | |
+-----+----+---------------+--------------+-----------+------------+
| 4 |0x04|CR-LSP |DoD | [<a href="./rfc3212" title=""Constraint-Based LSP Setup using LDP"">RFC3212</a>] | |
| | | | | [<a href="./rfc7358">RFC7358</a>] | |
+-----+----+---------------+--------------+-----------+------------+
| 5 |0x05|Typed Wildcard |Not applicable| [<a href="./rfc5918" title=""Label Distribution Protocol (LDP) 'Typed Wildcard' Forward Equivalence Class (FEC)"">RFC5918</a>] | |
| | |FEC Element | | [<a href="./rfc7358">RFC7358</a>] | |
+-----+----+---------------+--------------+-----------+------------+
| 6 |0x06|P2MP |DU | [<a href="./rfc6388" title=""Label Distribution Protocol Extensions for Point-to-Multipoint and Multipoint-to-Multipoint Label Switched Paths"">RFC6388</a>] | |
| | | | | [<a href="./rfc7358">RFC7358</a>] | |
+-----+----+---------------+--------------+-----------+------------+
| 7 |0x07|MP2MP-up |DU | [<a href="./rfc6388" title=""Label Distribution Protocol Extensions for Point-to-Multipoint and Multipoint-to-Multipoint Label Switched Paths"">RFC6388</a>] | |
| | | | | [<a href="./rfc7358">RFC7358</a>] | |
+-----+----+---------------+--------------+-----------+------------+
| 8 |0x08|MP2MP-down |DU | [<a href="./rfc6388" title=""Label Distribution Protocol Extensions for Point-to-Multipoint and Multipoint-to-Multipoint Label Switched Paths"">RFC6388</a>] | |
| | | | | [<a href="./rfc7358">RFC7358</a>] | |
+-----+----+---------------+--------------+-----------+------------+
| 9 |0x09|HSMP-upstream |DU | [<a href="./rfc7140" title=""LDP Extensions for Hub and Spoke Multipoint Label Switched Path"">RFC7140</a>] | 2014-01-09 |
| | | | | [<a href="./rfc7358">RFC7358</a>] | |
+-----+----+---------------+--------------+-----------+------------+
| 10 |0x0A|HSMP-downstream|DU, Upstream | [<a href="./rfc7140" title=""LDP Extensions for Hub and Spoke Multipoint Label Switched Path"">RFC7140</a>] | 2014-01-09 |
| | | | | [<a href="./rfc7358">RFC7358</a>] | |
+-----+----+---------------+--------------+-----------+------------+
| 128 |0x80|PWid |DU | [<a href="./rfc4447" title=""Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)"">RFC4447</a>] | |
| | |FEC Element | | [<a href="./rfc7358">RFC7358</a>] | |
+-----+----+---------------+--------------+-----------+------------+
| 129 |0x81|Generalized |DU | [<a href="./rfc4447" title=""Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)"">RFC4447</a>] | |
| | |PWid | | [<a href="./rfc7358">RFC7358</a>] | |
| | |FEC Element | | | |
+-----+----+---------------+--------------+-----------+------------+
| 130 |0x82|P2MP PW |Upstream | [<a href="#ref-P2MP-PW" title=""Signaling Root-Initiated Point-to-Multipoint Pseudowire using LDP"">P2MP-PW</a>] | 2009-06-03 |
| | |Upstream | | [<a href="./rfc7358">RFC7358</a>] | |
| | |FEC Element | | | |
+-----+----+---------------+--------------+-----------+------------+
<span class="grey">Raza, et al. Standards Track [Page 5]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-6" ></span>
<span class="grey"><a href="./rfc7358">RFC 7358</a> Label Advert. Discipline for LDP FECs October 2014</span>
+-----+----+---------------+--------------+-----------+------------+
| 131 |0x83|Protection |DU |[<a href="#ref-FAST-PROT" title=""PW Endpoint Fast Failure Protection"">FAST-PROT</a>]| 2010-02-26 |
| | |FEC Element | | [<a href="./rfc7358">RFC7358</a>] | |
+-----+----+---------------+--------------+-----------+------------+
| 132 |0x84|P2MP PW |DU | [<a href="#ref-P2MP-PW" title=""Signaling Root-Initiated Point-to-Multipoint Pseudowire using LDP"">P2MP-PW</a>] | 2014-04-04 |
| | |Downstream | | [<a href="./rfc7358">RFC7358</a>] | |
| | |FEC Element | | | |
+-----+----+---------------+--------------+-----------+------------+
<span class="h2"><a class="selflink" id="section-5" href="#section-5">5</a>. References</span>
<span class="h3"><a class="selflink" id="section-5.1" href="#section-5.1">5.1</a>. Normative References</span>
[<a id="ref-RFC3212">RFC3212</a>] Jamoussi, B., Ed., Andersson, L., Callon, R., Dantu, R.,
Wu, L., Doolan, P., Worster, T., Feldman, N., Fredette,
A., Girish, M., Gray, E., Heinanen, J., Kilty, T., and A.
Malis, "Constraint-Based LSP Setup using LDP", <a href="./rfc3212">RFC 3212</a>,
January 2002, <<a href="http://www.rfc-editor.org/info/rfc3212">http://www.rfc-editor.org/info/rfc3212</a>>.
[<a id="ref-RFC4447">RFC4447</a>] Martini, L., Ed., Rosen, E., El-Aawar, N., Smith, T., and
G. Heron, "Pseudowire Setup and Maintenance Using the
Label Distribution Protocol (LDP)", <a href="./rfc4447">RFC 4447</a>, April 2006,
<<a href="http://www.rfc-editor.org/info/rfc4447">http://www.rfc-editor.org/info/rfc4447</a>>.
[<a id="ref-RFC5036">RFC5036</a>] Andersson, L., Ed., Minei, I., Ed., and B. Thomas, Ed.,
"LDP Specification", <a href="./rfc5036">RFC 5036</a>, October 2007,
<<a href="http://www.rfc-editor.org/info/rfc5036">http://www.rfc-editor.org/info/rfc5036</a>>.
[<a id="ref-RFC5918">RFC5918</a>] Asati, R., Minei, I., and B. Thomas, "Label Distribution
Protocol (LDP) 'Typed Wildcard' Forward Equivalence Class
(FEC)", <a href="./rfc5918">RFC 5918</a>, August 2010,
<<a href="http://www.rfc-editor.org/info/rfc5918">http://www.rfc-editor.org/info/rfc5918</a>>.
[<a id="ref-RFC6388">RFC6388</a>] Wijnands, IJ., Ed., Minei, I., Ed., Kompella, K., and B.
Thomas, "Label Distribution Protocol Extensions for
Point-to-Multipoint and Multipoint-to-Multipoint Label
Switched Paths", <a href="./rfc6388">RFC 6388</a>, November 2011,
<<a href="http://www.rfc-editor.org/info/rfc6388">http://www.rfc-editor.org/info/rfc6388</a>>.
[<a id="ref-RFC6389">RFC6389</a>] Aggarwal, R. and JL. Le Roux, "MPLS Upstream Label
Assignment for LDP", <a href="./rfc6389">RFC 6389</a>, November 2011,
<<a href="http://www.rfc-editor.org/info/rfc6389">http://www.rfc-editor.org/info/rfc6389</a>>.
[<a id="ref-RFC7140">RFC7140</a>] Jin, L., Jounay, F., Wijnands, IJ., and N. Leymann, "LDP
Extensions for Hub and Spoke Multipoint Label Switched
Path", <a href="./rfc7140">RFC 7140</a>, March 2014,
<<a href="http://www.rfc-editor.org/info/rfc7140">http://www.rfc-editor.org/info/rfc7140</a>>.
<span class="grey">Raza, et al. Standards Track [Page 6]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-7" ></span>
<span class="grey"><a href="./rfc7358">RFC 7358</a> Label Advert. Discipline for LDP FECs October 2014</span>
<span class="h3"><a class="selflink" id="section-5.2" href="#section-5.2">5.2</a>. Informative References</span>
[<a id="ref-FAST-PROT">FAST-PROT</a>] Shen, Y., Aggarwal, R., Henderickx, W., and Y. Jiang,
"PW Endpoint Fast Failure Protection", Work in Progress,
<a href="./draft-ietf-pwe3-endpoint-fast-protection-01">draft-ietf-pwe3-endpoint-fast-protection-01</a>, July 2014.
[<a id="ref-P2MP-PW">P2MP-PW</a>] Sivabalan, S., Ed., Boutros, S., Ed., Martini, L.,
Konstantynowicz, M., Del Vecchio, G., Nadeau, T., Jounay,
F., Niger, P., Kamite, Y., Jin, L., Vigoureux, M.,
Ciavaglia, L., Delord, S., and K. Raza, "Signaling
Root-Initiated Point-to-Multipoint Pseudowire using LDP",
Work in Progress, <a href="./draft-ietf-pwe3-p2mp-pw-04">draft-ietf-pwe3-p2mp-pw-04</a>, March 2012.
<span class="grey">Raza, et al. Standards Track [Page 7]</span></pre>
<hr class='noprint'/><!--NewPage--><pre class='newpage'><span id="page-8" ></span>
<span class="grey"><a href="./rfc7358">RFC 7358</a> Label Advert. Discipline for LDP FECs October 2014</span>
Acknowledgments
We acknowledge Eric Rosen and Rajiv Asati for their initial review
and input on the document.
Authors' Addresses
Kamran Raza
Cisco Systems, Inc.
2000 Innovation Drive
Ottawa, ON K2K-3E8
Canada
EMail: skraza@cisco.com
Sami Boutros
Cisco Systems, Inc.
3750 Cisco Way
San Jose, CA 95134
United States
EMail: sboutros@cisco.com
Luca Martini
Cisco Systems, Inc.
9155 East Nichols Avenue, Suite 400
Englewood, CO 80112
United States
EMail: lmartini@cisco.com
Nicolai Leymann
Deutsche Telekom AG
Winterfeldtstrasse 21
Berlin 10781
Germany
EMail: N.Leymann@telekom.de
Raza, et al. Standards Track [Page 8]
</pre>
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