One document matched: draft-mirsky-mpls-tp-cv-adv-00.xml
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<rfc category="std" ipr="trust200902" docName="draft-mirsky-mpls-tp-cv-adv-00">
<?xml-stylesheet type='text/xsl' href='rfc2629.xslt' ?>
<front>
<title abbrev='VCCV MPLS-TP CV'>VCCV MPLS-TP Connectivity Verification (CV) Capability Advertisement</title>
<author initials='G.' surname="Mirsky" fullname='Greg Mirsky'>
<organization>Ericsson</organization>
<address>
<email>gregory.mirsky@ericsson.com</email>
</address>
</author>
<date day="22" month="February" year="2012" />
<area>Routing</area>
<workgroup>Network Working Group</workgroup>
<keyword>Internet-Draft</keyword>
<keyword>PW VCCV</keyword>
<keyword>MPLS-TP CC/CV/RDI</keyword>
<keyword>T-LDP </keyword>
<abstract>
<t>
This document specifies how use of proactive Connectivity Verification, Continuity
Check, and Remote Defect Indication for the MPLS Transport Profile <xref target="RFC6428"/> affects operation and management
function election for PW VCCV <xref target="RFC5085"/>, <xref target="RFC5885"/>.
</t>
</abstract>
</front>
<middle>
<section anchor="intro" title="Introduction">
<t>
Proactive Connectivity Verification (CV), Continuity Check (CC), and Remote Defect Indication (RDI) for the MPLS Transport Profile <xref target="RFC6428"></xref>
is applicable to all constructs of the MPLS-TP, including pseudowires (PWs). If Control Plane is used to operate and manage PW
then procedure defined in <xref target="RFC5085"/> and <xref target="RFC5885"></xref> should be used to select proper type of Control Channel and corresponding
type of Connectivity Verification. This document specifies how signaling and selection process modified to ensure backward compatibility
and allow use of proactive CV-CC-RDI over MPLS-TP PWs.
</t>
<section title="Conventions used in this document">
<section title="Terminology">
<t>BFD: Bidirectional Forwarding Detection
</t>
<t>CC: Continuity Check
</t>
<t>CV: Connectivity Verification
</t>
<t>PE: Provider Edge
</t>
<t>VCCV: Virtual Circuit Connectivity Verification
</t>
<t>VCCV CC: VCCV Control Channel
</t>
</section>
<section title="Requirements Language">
<t>
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
<xref target="RFC2119"></xref>.
</t>
</section>
</section>
</section>
<section anchor="cc-cv-pw" title="MPLS-TP CC-CV on Pseudowires">
<t>
PW VCCV can support several CV Types. Ability to support arbitrary combination of CV modes
advertised in CV Types field of VCCV Interface Parameter sub-TLV <xref target="RFC4446"/>, <xref target="RFC4447"/>.
Currently six types of CV been defined for PW VCCV out of eight bit long field. This document
introduces four new CV types and to accommodate them a new VCCV Extended CV parameter
for PW Interface Parameters Sub-TLV is defined.
</t>
<section anchor="vccv-ext-sub-tlv" title="VCCV Extended CV Advertisement sub-TLV">
<t>
The format of VCCV Extended CV Advertisement is a TLV where:
</t>
<figure align="left" anchor="vccv-ext-cv-param"
title="VCCV Extended CV parameter format">
<artwork><![CDATA[
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = 0x19 | Length = 0x04 | Reserved | CV Type |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
]]></artwork>
</figure>
<t>
Reserved field must be set to zeroes on transmit and ignored on receive.
</t>
<t>
CV Type field is a bitmask that lists types of CV monitoring that a PE is capable
to support. VCCV Extended CV parameter sub-TLV must appear in combination
with VCCV parameter sub-TLV. If VCCV parameter sub-TLV is missing then VCCV
Extended CV parameter sub-TLV should be ignored.
</t>
</section>
<section anchor="cc-cv-types" title="MPLS-TP CC-CV Types">
<t>
The <xref target="RFC6428"/> defines coordinated and independent modes of monitoring point-to-point
bi-directional connection that can be applied to monitoring PWs. At the same time <xref target="RFC6310"/>
defines how BFD-based OAM can map and be mapped to status of an Attachment Circuit.
Thus there could be four MPLS-TP CV types as combination of modes and functionality:
</t>
<texttable anchor="bitmask_values_tbl" title="Bitmask Values for MPLS-TP CV Types">
<ttcol align='center'>Modes</ttcol>
<ttcol align='center'>Fault Detection Only</ttcol>
<ttcol align='center'>Fault Detection and Status Signalling</ttcol>
<c>Independent Mode</c>
<c>0x01</c>
<c>0x02</c>
<c>Coordinated Mode</c>
<c>0x04</c>
<c>0x08</c>
</texttable>
</section>
<section anchor="cc-cv-operation" title="MPLS-TP CC-CV Type Operation">
<t>
Connectivity verification according to <xref target="RFC6428"/> is part of MPLS-TP CC/CV
operation that can be used with VCCV Control Channel Types 1 <xref target="RFC5085"/> or
Type 4 <xref target="I-D.ietf-pwe3-vccv-for-gal" />. If VCCV CC Type 1 or Type 4 selected, then PEs might select one of MPLS-TP
CC-CV types as VCCV CV mechanism to be used for this PW.
</t>
</section>
<section anchor="cv-type-select" title="CV Type Selection">
<t>
CV selection rules that have been defined in Section 7 of <xref target="RFC5085"/> and updated Section 4
of <xref target="RFC5885"/> are augmented in this document.
</t>
<t>
If VCCV Control Channel Type 1 or Type 4 is chosen according to Section 7 <xref target="RFC5085"/>
or Section 4 <xref target="I-D.ietf-pwe3-vccv-for-gal" /> and common set of proactive CV types advertized by both PEs includes
MPLS-TP CC-CV types and some BFD CV types, then MPLS-TP CC-CV takes precedence
over any type of BFD CV. If multiple MPLS-TP CV types advertised by both PEs, then
following list sorted in descending priority order is used:
</t>
<t>
<list style="numbers">
<t>
0x08 - coordinated mode for PW Fault Detection and AC/PW Fault Status Signaling
</t>
<t>
0x04 - coordinated mode for PW Fault Detection only
</t>
<t>
0x02 - independent mode for PW Fault Detection and AC/PW Fault Status Signaling
</t>
<t>
0x01 - independent mode for PW Fault Detection only </t>
</list>
</t>
</section>
</section>
<section anchor="iana-consider" title="IANA Considerations">
<t>
The PW Interface Parameters Sub-TLV registry defined in <xref target="RFC4446"/>.
</t>
<t>
IANA is requested to reserve a new PW Interface Parameters Sub-TLV type as follows:
</t>
<texttable anchor="ext-vccv-param-tbl" title="New PW Interface Parameters Sub-TLV">
<ttcol align='center'>Parameter ID</ttcol>
<ttcol align='left'>Length</ttcol>
<ttcol align='center'>Description</ttcol>
<ttcol align='left'>Reference</ttcol>
<c>0x19</c>
<c>4</c>
<c>VCCV Extended CV Parameter</c>
<c>This document</c>
</texttable>
<t>Parameter ID Length Description Reference</t>
<t>0x19 4 VCCV Extended CV parameter This document</t>
<section title="VCCV Extended CV Types">
<t>
IANA is requested to set up a registry of ?VCCV Extended CV Types?. These are 8 bitfield
values. Extended CV Type values 0x01, 0x02, 0x04 and 0x08 are specified in
<xref target="cc-cv-types"/> of this document. The remaining bitfield values (0x10
through 0x80) are to be assigned by IANA using the "IETF Consensus" policy defined in
<xref target="RFC2434"/>. A VCCV Extended Control Verification Type description and a reference to an
RFC approved by the IESG are required for any assignment from this registry.
</t>
<texttable anchor="cv_types_tbl" title="MPLS Connectivity Verification (CV) Types">
<ttcol align='center'>Bit(Value)</ttcol>
<ttcol align='left'>Description</ttcol>
<c>Bit 0 (0x01)</c>
<c>Independent mode for PW Fault Detection only</c>
<c>Bit 1 (0x02)</c>
<c>Independent mode for PW Fault Detection and AC/PW Fault Status Signaling</c>
<c>Bit 2 (0x04)</c>
<c>Coordinated mode for PW Fault Detection only</c>
<c>Bit 3 (0x08)</c>
<c>Coordinated mode for PW Fault Detection and AC/PW Fault Status Signaling</c>
<c>Bit 4 (0x10)</c>
<c>Reserved</c>
<c>Bit 5 (0x20)</c>
<c>Reserved</c>
<c>Bit 6 (0x40)</c>
<c>Reserved</c>
<c>Bit 7 (0x80)</c>
<c>Reserved</c>
</texttable>
</section>
</section>
<section anchor="security" title="Security Considerations">
<t>
Routers that implement the additional CV Type defined herein are subject to the same security considerations
as defined in <xref target="RFC5085"/>, <xref target="RFC5880"/>, <xref target="RFC5881"/>, and <xref target="RFC6428"/>. This specification does not raise any
additional security issues beyond these.
</t>
</section>
<section title="Acknowledgements">
<t>
The author gratefully acknowledges the thoughtful review, comments, and explanations provided by Dave Allan.
</t>
</section>
</middle>
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&RFC6310;
&RFC5885;
&RFC5085;
&RFC5880;
&RFC5881;
&RFC5882;
&RFC4446;
&RFC4447;
&VCCV-GAL-PW;
</references>
<references title="Informative References">
<?rfc include='reference.RFC.2434'?>
<!--?rfc.include='reference.IANA'?-->
</references>
</back>
</rfc>
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