One document matched: draft-bryant-jwt-mplstp-report-00.xml
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<rfc category="info" docName="draft-bryant-jwt-mplstp-report-00"
ipr="full3978">
<front>
<title abbrev="JWT MPLS-TP Report">JWT Report on MPLS Architectural
Considerations for a Transport Profile</title>
<author fullname="Stewart Bryant" initials="S" role="editor"
surname="Bryant">
<organization>Cisco Systems</organization>
<address>
<postal>
<street>250, Longwater, Green Park,</street>
<city>Reading</city>
<code>RG2 6GB, UK</code>
<country>UK</country>
</postal>
<email>stbryant@cisco.com</email>
</address>
</author>
<author fullname="Loa Andersson" initials="L" role="editor"
surname="Andersson">
<organization>Acreo AB</organization>
<address>
<postal>
<street>Isafjordsgatan 22</street>
<city>Kista</city>
<region></region>
<code></code>
<country>Sweden</country>
</postal>
<phone></phone>
<facsimile></facsimile>
<email>loa@pi.nu</email>
<uri></uri>
</address>
</author>
<date year="2008" />
<area>Routing Area</area>
<workgroup>Network Working Group</workgroup>
<keyword>Sample</keyword>
<keyword>Draft</keyword>
<abstract>
<t>This RFC archives the report of the IETF - ITU-T Jooint Working Team
(JWT) on the application of MPLS to Transport Networks. The JWT
recommended of Option 1: The IETF and the ITU-T jointly agree to work
together and bring transport requirements into the IETF and extend IETF
MPLS forwarding, OAM, survivability, network management and control
plane protocols to meet those requirements through the IETF Standards
Process. There are two versions of this RFC. An ASCII version that
contains a summary of the slides and a pdf version that contains the
summary and a copy of the slides.</t>
</abstract>
</front>
<middle>
<section title="Introduction">
<t>For a number of years the ITU-T has been designing a label switched
protocol to be used in Transport Networks. A Transport Network can be
considered to be the network that provides wide area connectivity upon
which other services such IP, or the phone network run. The ITU-T chose
to adapt the IETF’s MPLS to this task, and introduced a protocol
suite known as T-MPLS.</t>
<t>Quite late in the ITU-T design and specification cycle, there were a
number of liaison exchanges between the ITU-T and the IETF concerning
this technology <xref target="T-MPLS1"></xref>, and the chairs of the
MPLS, PWE3, BFD and CCAMP working groups as well as the Routing and
Internet Area Directors attended a number of ITU-T meetings. During this
process the IETF became increasingly concerned that the incompatibility
of IETF MPLS and ITU-T T-MPLS would lead to a “train wreck on the
Internet”. These concerns led the chairs of the IESG and IAB to
take the step of sending a liaison to the ITU-T, stating that either
T-MPLS should become and fully compliant MPLS protocol, standardized
under the IETF process (the so called “Option 1”), or it
should become a completely disjoint protocol with a new name and
completely new set of code points (the so called “Option
2”)<xref target="Ethertypes"></xref>.</t>
<t>Option 1 and Option 2 were discussed at an ITU-T meeting of Question
12 Study Group 15 in Stuttgart <xref target="Stuttgart"></xref>, where
it was proposed that a Joint (ITU-T – IETF) Team should be formed
to evaluate the issues, and make a recommendation to ITU-T management on
the best way forward.</t>
<t>Following discussion between the management of the IETF and the ITU-T
a Joint Working Team (JWT) was established, this was supported by an
IETF Design Team and an Ad Hoc Group on T-MPLS in the ITU-T <xref
target="ahtmpls"></xref>. The first meeting of the Ad Hoc group occurred
during the ITU-T Geneva Plenary in February this year. As a result of
the work of the JWT and the resulting agreement on a way forward, the
fears that a set of next-generation network transport specifications
developed by ITU-T could cause interoperability problems were
allayed.</t>
<t>The JWT submitted their report to ITU-T and IETF management in the
form of a set of powerpoint slides <xref target="MPLS-TP-22"></xref>
[ALSO INCLUDE SELF REF TO PDF WHEN AVALIABLE]. The ITU-T have accepted
this recommendation, as documented in <xref target="MPLS-TP"></xref>.
This RFC archives the JWT report in a format that is accessable to the
IETF.</t>
<t>There are two versions of this RFC. An ASCII version that contains a
summary of the slides and a pdf version that contains the summary and a
copy of the slides. In the case of a conflict between the summary and
the slides, the slides have normacy. Since those slides were the basis
of an important agreement between the the IETF and the ITU-T, it should
further be noted that In the event that the pdf verson of the slides
differ from those emailed to ITU-T and IETF management on 18th April
2008 by the co-chairs of the JWT, the emailed slides have normacy.</t>
</section>
<section title="Executive Summary">
<t>Slides 4 to 10 provide an executive summary of the JWT Report. The
following is a summary of those slides:</t>
<t>The JWT acheived consensus on the recommendation of Option 1: to
jointly agree to work together and bring transport requirements into the
IETF and extend IETF MPLS forwarding, OAM, survivability, network
management and control plane protocols to meet those requirements
through the IETF Standards Process. The Joint Working Team believed that
this would fulfill the mutual goal of improving the functionality of the
transport networks and the internet and guaranteeing complete
interoperability and architectural soundness. This technolgy would be
refered to as the Transport Profile for MPLS (MPLS-TP)</t>
<t>The JWT recommend that future work should focus on:</t>
<t>In the IETF: <list>
<t>Definition of the MPLS “Transport Profile”
(MPLS-TP)</t>
</list> In the ITU-T: <list>
<t>Integration of MPLS-TP into the transport network</t>
<t>Alignment of the current T-MPLS Recommendations with MPLS-TP
and,</t>
<t>Terminate the work on current T-MPLS</t>
</list>The technical feasibility analysis demonstrated there were no
“show stopper” issues in the recommendation of Option 1 and
that the IETF MPLS and Pseudowire architecture could be extended to
support transport functional requirements. Therefore the team believed
that there was no need for the analysis of any other option.</t>
<t>The JWT proposed that the MPLS Interoperability Design Team (MEAD
Team), JWT and ad hoc T-MPLS groups continue as described in SG15
TD515/PLEN <xref target="JWTcreation"></xref> with the following
roles:<list>
<t>Facilitate the rapid exchange of information between the IETF and
ITU-T</t>
<t>Ensure that the work is progressing with a consistent set of
priorities</t>
<t>Identify gaps/inconsistencies in the solutions under
development</t>
<t>Propose solutions for consideration by the appropriate
WG/Question</t>
<t>Provide guidance when work on a topic is stalled or technical
decision must be mediated</t>
</list>None of these groups would have the authority to create or
modify IETF RFCs or ITU-T Recommendations. Any such work would be
progressed via the normal process of the respective standards body.
Direct participation in the work by experts from the IETF and ITU-T
would be required.</t>
<t>The JWT recommended that the normative definition of the MPLS-TP that
supports the ITU-T transport network requirements will be captured in
IETF RFCs. It proposed that the ITU-T should:<list>
<t>Develop Recommendations to allow MPLS-TP to be integrated with
current transport equipment and networks Including in agreement with
the IETF, the definition of any ITU-T specific functionality within
the MPLS-TP architecture via the MPLS change process (RFC 4929)</t>
<t>Revise existing Recommendations to align with MPLS-TP</t>
<t>ITU-T Recommendations will make normative references to the
appropriate RFCs</t>
</list></t>
<t>The executive summary contains a number of detailed recommendations
to both IETF and ITU-T management together with proposed document
structure and timetable.</t>
<t>These recommendations were accepted by ITU-T management [REF]</t>
</section>
<section title="Introduction and Background Material">
<t>Slides 11 to 22 provide introductory and background material.</t>
<t>The starting point of the analysis was to attempt to satisfy option 1
by showing the high level architecture, any show stoppers and the design
points that would need to be addressed after the decision has been made
to work together. Option 1 was stated as preferred by the IETF and
because Option 1 was shown to be feasible, Option 2 was not
explored.</t>
<t>The work was segmented into five groups looking at: Forwarding, OAM,
Protection, Control Plane and Network Management. The outcome of each
review was reported in following sections and is summarised below.</t>
<t>There followed a detailed description of the overall requirements and
architectural assumptions that would be used in the remainder of the
work.</t>
</section>
<section title="High Level Architecture ">
<t>Slides 23 to 28 provide a high level architectural view of the
proposed design.</t>
<t>The spectrum of services that MPLS-TP needs to address and the wider
MPLS context is described, together with the provisioning issues. Some
basic terminology needed to understand the MPLS-TP is defined and some
context examples provided.</t>
</section>
<section title="OAM and Forwarding">
<t>Slides 29 to 32 describe the OAM requirements and talk about segment
recovery and node identification.</t>
<t>Slides 33 to 38 introduce OAM hierarchy and describe LSP monitoring,
the MEP and MIP relationship and the LSP and PW monitoring
relationship.</t>
<t>Sides 39 to 46 introduce the Associated Channel Header and its
generalisation to carry the OAM over LSPs through the use of the "Label
for You" (LFU).</t>
<t>Slides 47 to 48 provide a didactic description of how the forwarding
and the ACH OAM mechanism work in detail. A significant number of
scenarios are described to work through the operation on a case by case
basis. These slides introduce a new textual notation to simplify the
description of complex MPLS stacks.</t>
<t>Note that the MPLS forwarding, as specified by the IETF RFCs,
requires no changes to support MPLS-TP</t>
</section>
<section title="Control Plane">
<t>Sides 79 to 83 discuss various aspects of the control plane
design.</t>
<t>Control plane sub-team stated that existing IETF protocols can be
used to provide required functions for transport network operation and
DCN/SCN operation. IETF GMPLS protocols have already applied to ASON
architecture, and the JWT considered that any protocol extensions needed
will be easy to make. The slides provide a number of scenarios to
demonstrate this conclusion.</t>
</section>
<section title="Survivability">
<t>The survivability considerations are provided in slides 95 to 104</t>
<t>Survivability sub-team did nit find any issues that prevented the
creation of an MPLS-TP, and therefore recommended that Option 1 be
selected. Three potential solutions were identified. Each solutions has
different attributes and advantages, and thought that further work in
the design phase should eliminate one or more of these options and/or
provide an applicability statement.</t>
<t>After some clarifications and discussion there follow in the slide
set a number of linear and ring protection scenarios with examples of
how they might be addressed.</t>
</section>
<section title="Network Management">
<t>Slide 106 States the conclusion of the Network Management sub team :
that they found no issues that prevent the creation of an MPLS-TP and
hence Option 1 can be selected.</t>
</section>
<section title="Summary">
<t>Slide 113 Provides a summary of the JWT report.</t>
<t>The JWT found no show stoppers and everyone was in agreement that
they had identified a viable solution. They therefore recommend Option
1. They stated that in their view it is technically feasible that the
existing MPLS architecture can be extended to meet the requirements of a
Transport profile, and that the architecture allows for a single OAM
technology for LSPs, PWs and a deeply nested network. From probing
various ITU-T Study Groups and IETF Working Groups it appears that MPLS
reserved label 14 has had wide enough implementation and deployment that
the solution may have to use a different reserved label (e.g. Label 13).
The JWT recommended that extensions to Label 14 should cease.</t>
<t>The JWT further recommended that this architecture appeared to
subsume Y.1711 since the requirements can be met by the mechanism
proposed in their report.</t>
</section>
<section title="IANA considerations ">
<t>There are no IANA considerations that arise from this draft.</t>
<t>Any IANA allocations needed to implement the JWT recommendation will
be requested in the standards track RFCs that define the MPLS-TP
protocol.</t>
</section>
<section title="Security Considerations">
<t>The only security consideration that arises as a result of this RFC
is the need to ensure that this is a faithful representation of the JWT
report.</t>
<t>The protocol work that arises from this agreement will have technical
security requirements which will be identified in the RFCs that define
MPLS-TP.</t>
</section>
<section title="The JWT Report">
<t>In the PDF version of this RFC [REF to PDF VERSION] there follows the
JWT report as a set of slides.</t>
<t><vspace blankLines="21" /></t>
</section>
</middle>
<back>
<references title="Informative References"></references>
<references title="URL References">
<reference anchor="MPLS-TP-22">
<front>
<title>http://www.ietf.org/MPLS-TP_overview-22.pdf</title>
<author>
<organization>IETF - ITU-T Joint Working Team</organization>
</author>
<date year="2008" />
</front>
</reference>
<reference anchor="T-MPLS1">
<front>
<title>Various ITU-T and IETF Liaison Statements Concerning T-MPLS,
https://datatracker.ietf.org/liaison/</title>
<author>
<organization>IETF and ITU-T</organization>
</author>
<date year="" />
</front>
</reference>
<reference anchor="Ethertypes">
<front>
<title>T-MPLS use of the MPLS Ethertypes,
https://datatracker.ietf.org/documents/LIAISON/file366.txt</title>
<author>
<organization>ITU-T, SG 15 Question 12</organization>
</author>
<date year="2006" />
</front>
</reference>
<reference anchor="Stuttgart">
<front>
<title>Report of interim meeting of Q.12 on T-MPLS - Stuttgart,
Germany, 12-14 September , 2007, Annex
4,http://ties.itu.int/u//tsg15/sg15/xchange/wp3/200709_joint_q12_q14_stuttgart/T-MPLS/wdt03_rapporteur_report-final.doc</title>
<author>
<organization>IETF - IESG and IAB Chairs</organization>
</author>
<date year="2006" />
</front>
</reference>
<reference anchor="JWTcreation">
<front>
<title>Proposal to establish an Ad Hoc group on T-MPLS,
http://www.itu.int/md/T05-SG15-080211-TD-PLEN-0515/en</title>
<author>
<organization>Chairman, ITU-T SG 15</organization>
</author>
<date year="2008" />
</front>
</reference>
<reference anchor="ahtmpls">
<front>
<title>Ad Hoc group on T-MPLS,
http://www.itu.int/ITU-T/studygroups/com15/ahtmpls.html</title>
<author>
<organization></organization>
</author>
<date year="2008" />
</front>
</reference>
<reference anchor="MPLS-TP">
<front>
<title>IETF and ITU-T cooperation on extensions to MPLS for
transport network functionality,
https://datatracker.ietf.org/liaison/446/</title>
<author>
<organization></organization>
</author>
<date year="2008" />
</front>
</reference>
</references>
</back>
</rfc>| PAFTECH AB 2003-2026 | 2026-04-23 10:57:52 |