One document matched: draft-dhody-pce-pcep-p2mp-per-destination-03.xml
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<rfc ipr="trust200902" category="exp" docName="draft-dhody-pce-pcep-p2mp-per-destination-03" obsoletes="" updates="" submissionType="IETF" xml:lang="en">
<front>
<title abbrev="EXPLICIT-INC-EXC-ABSTRACT-NODES">Supporting explicit inclusion or exclusion of abstract nodes for a subset of P2MP destinations in Path Computation Element Communication Protocol (PCEP). </title>
<author initials="D" surname="Dhody" fullname="Dhruv Dhody">
<organization>Huawei Technologies India Pvt Ltd</organization>
<address>
<postal>
<street>Leela Palace</street>
<city>Bangalore</city>
<region>Karnataka</region>
<code>560008</code>
<country>INDIA</country>
</postal>
<email>dhruv.dhody@huawei.com</email>
</address>
</author>
<author initials="U" surname="Palle" fullname="Udayasree Palle">
<organization>Huawei Technologies India Pvt Ltd</organization>
<address>
<postal>
<street>Leela Palace</street>
<city>Bangalore</city>
<region>Karnataka</region>
<code>560008</code>
<country>INDIA</country>
</postal>
<email>udayasree.palle@huawei.com</email>
</address>
</author>
<author initials="V" surname="Kondreddy" fullname="Venugopal Reddy Kondreddy">
<organization>Huawei Technologies India Pvt Ltd</organization>
<address>
<postal>
<street>Leela Palace</street>
<city>Bangalore</city>
<region>Karnataka</region>
<code>560008</code>
<country>INDIA</country>
</postal>
<email>venugopalreddyk@huawei.com</email>
</address>
</author>
<date month="October" year="2012" />
<area>Routing</area>
<workgroup>PCE Working Group</workgroup>
<abstract>
<t>The ability to determine paths of point-to-multipoint (P2MP) Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS) Traffic Engineering Label Switched Paths (TE LSPs) is one the key requirements for Path Computation Element (PCE). <xref target="RFC6006"/> and <xref target="PCE-P2MP-PROCEDURES"/> describes these mechanisms for intra and inter domain path computation via PCE. </t>
<t>This document describes the need for explicitly specifying abstract nodes for inclusion or exclusion for a subset of destinations during the Point to Multipoint (P2MP) path computation via PCE. Further an extension to the PCE communication Protocol (PCEP) for P2MP is suggested to support this.</t>
</abstract>
</front>
<middle>
<section title="Introduction" toc="default">
<t>The Path Computation Element (PCE) architecture is defined in <xref target="RFC4655"/>. <xref target="RFC5862"/> lay out the requirements for Path Computation Client (PCC) and Path Computation Element (PCE) to support Point-to-Multipoint (P2MP) path computation. <xref target="RFC6006"/> describe an extension to PCEP to compute optimal constrained intra-domain (G)MPLS P2MP TE LSPs. <xref target="PCE-P2MP-PROCEDURES"/> describes the mechanism for inter-domain P2MP path computation. </t>
<t><xref target="PCE-P2MP-PROCEDURES"/> describes the core-tree procedure for computing inter-domain P2MP tree. It assumes that, due to deployment and commercial limitations, the sequence of domains for a path (the path domain tree) will be known in advance. For a group of destination which belong to a destination domain, the domain-sequence needs to be encoded seperately as described in [DOMAIN-SEQ]. The mechanism of explicitly specifying abstract nodes for inclusion or exclusion for a subset of destinations can be used for this purpose, where abstract nodes are domains. </t>
<t><xref target="RFC6006"/> describe a PCE-based path computation procedure to compute optimal constrained (G)MPLS P2MP TE LSPs. It describes mechanism to specify branch nodes that can or cannot be used via Branch Node Capability (BNC) object (which only supports IPv4 and IPv6 prefix sub-objects). This document adds the capability to explicitly specify any abstract nodes for inclusion or exclusion for a subset of destinations.</t>
<section title="Requirements Language" toc="default">
<t>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 <xref target="RFC2119"/>.</t>
</section>
</section>
<section title="Terminology" toc="default">
<t>The following terminology is used in this document.</t>
<t>
<list style="hanging">
<t hangText="IRO:">Include Route Object.</t>
<t hangText="PCC:">Path Computation Client: any client application requesting a path computation to be performed by a Path Computation Element.</t>
<t hangText="PCE:">Path Computation Element. An entity (component, application, or network node) that is capable of computing a network path or route based on a network graph and applying computational constraints.</t>
<t hangText="P2MP:">Point-to-Multipoint</t>
<t hangText="P2P:">Point-to-Point</t>
<t hangText="RRO:">Record Route Object</t>
<t hangText="RSVP:">Resource Reservation Protocol</t>
<t hangText="TE LSP:">Traffic Engineering Label Switched Path.</t>
<t hangText="XRO:">Exclude Route Object.</t>
</list>
</t>
</section>
<section title="Motivation" toc="default">
<section title="Domain Sequence Tree in Inter Domain P2MP Path Computation" toc="default">
<t><xref target="PCE-P2MP-PROCEDURES"/> describes the core-tree procedure for inter-domain path computation. The procedure assumes that the sequence of domains for a path (the path domain tree) will be known in advance due to deployment and commercial limitations (e.g., inter-AS peering agreements).</t>
<t>In the <xref target="fig1"/> below, D1 is the root domain; D5 and D6 are the destination domains. The ingress is A in domain D1; egresses are X, Y in Domain D6 and Z in Domain D5. </t>
<t>
<figure title="Domain Topology Example" anchor="fig1" suppress-title="false" align="left" alt="" width="" height="">
<artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
|
| +-------------+ +----------------+
| |D 3 | |D 6 |
| | +--+| | +--+ |
| | |J || | |X | |
| | +--+ +--+| | +--+ +--+ |
| | |F | | | |U | |
| | *--+ | | +--+ |
| | / +--+ | | +--+ |
| |/ |K | | | |Y | |
| / +--+ | | +--+ +--+ |
| /| +--+ |+--------------+| |V | |
|/ | |G | ++-+ +-++ +--+ |
+-------------+/ | +--+ ||N| |S|| |
| /| | ++-+ +-++ |
| +--*|| +-------------+| |+----------------+
| |D ||| | +--+ |
| +--+|| | |P | |
| +--+ || | +--+ |
| |B | || | |
| +--+ || | |
| || | +--+ |
|+--+ || | |Q | |
||A | || | +--+ |
|+--+ || | |
| || | +--+ |
| +--+ || +------------+ | |R | |+----------------+
| |C | || |D 2 +-++ +--+ +-++ D 5 |
| +--+ || | |O|| |T|| |
| || | +-++ +-++ |
| +--+|| | +--+ | | D 4 || +--+ |
| |E ||| | |L | | +--------------+| |W | |
| +--*|| | +--+ | | +--+ |
| \| | | | +--+ |
|D 1 |\ | +--+ | | |Z | |
+-------------+|\ | |H | | | +--+ |
| \| +--+ +--+ | |
| \ |M | | |
| |\ +--+ | |
| | \ +--+ | | |
| | \|I | | | |
| | *--+ | | |
| | | | |
| +------------+ +----------------+
|
|
As 100 | AS 200
| ]]></artwork>
</figure>
</t>
<t>In the <xref target="fig2"/> below, the P2MP tree spans 5 domains. Destination in D6 (X & Y) would use the domain-sequence: D1-D3-D4-D6; and destination in D5 (Z) would use the domain-sequence: D1-D3-D4-D5.</t>
<t>
<figure title="Domain Sequence Tree" anchor="fig2" suppress-title="false" align="left" alt="" width="" height="">
<artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[
D3 D6
/ \ /
D1 D4
\
D5
]]></artwork>
</figure>
</t>
<t>Since destinations in different destination domain will have different domain sequence within the domain tree, it requires following encoding-</t>
<t>
<list style="symbols">
<t>Destination X and Y: D1-D3-D4-D6</t>
<t>Destination Z : D1-D3-D4-D5</t>
</list>
</t>
<t>An extension in P2MP Path Compuatation request is needed to support this. (Refer <xref target="SEC_REQ"/>)</t>
<t>The abstract nodes MAY include (but not limited to) domain subobjects AS number and IGP Area as described in <xref target="DOMAIN-SEQ"/>.</t>
</section>
<section title="Explicit inclusion or exclusion of abstract nodes" toc="default">
<t><xref target="RFC6006"/> describes four possible types of leaves in a P2MP request encoded in P2MP END-POINTS object.</t>
<t>
<list style="symbols">
<t>New leaves to add </t>
<t>Old leaves to remove </t>
<t>Old leaves whose path can be modified/reoptimized </t>
<t>Old leaves whose path must be left unchanged </t>
</list>
</t>
<t>Currently <xref target="RFC6006"/> only allows a list of nodes that can be used as branch nodes or a list of nodes that cannot be used as branch nodes by using the Branch Node Capability (BNC) Object, which applies to all leaves (old and new) in the P2MP tree.</t>
<t>For an existing P2MP tree which may already have a branch node through which most of the leaves are connected, but when adding a set of new leaves, administrator may want to exclude that branch node (as it may soon be overloaded) and would like to balance the final P2MP tree. This could be done explicitly by excluding a particular branch node or including a different branch node only for a set of new leaves encoded in the one P2MP END-POINTS object. </t>
<t>Administrator at the source can exert stronger control by providing explicit inclusion or exclusion of any abstract nodes (not limited to branch nodes) for a group (subset) of destinations. </t>
</section>
</section>
<section title="Detailed Description" toc="default">
<section title="Objective" toc="default">
<t><xref target="RFC6006"/> defines Request Message Format and Objects, along with <end-point-rro-pair-list>. This section introduce the use of <IRO> and <XRO> which are added to the <end-point-rro-pair-list>.</t>
<t>To allow abstract nodes to be explicitly included or excluded for a subset of destinations (encoded in one <END-POINTS> object), changes are made as shown below.</t>
<t>The abstract node (encoded as subobject in <IRO> and <XRO>) MAY be an absolute hop, IP-Prefix, Autonomous system or IGP Area. The subobjects are described in <xref target="RFC3209"/>, <xref target="RFC3477"/>, <xref target="RFC4874"/> and <xref target="DOMAIN-SEQ"/>.</t>
<t>Note that one P2MP Path request can have multiple <END-POINTS> objects and each P2MP <END-POINTS> object may have multiple destinations, the <IRO> and <XRO> is applied for all destinations in one such P2MP <END-POINTS> object.</t>
</section>
<section title="Request Message Format" toc="default" anchor="SEC_REQ">
<t>
<figure title="" suppress-title="false" align="left" alt="" width="" height="">
<artwork xml:space="preserve" name="" type="" align="left" alt="" width="" height=""><![CDATA[ The format of PCReq message is modified as follows:
<PCReq Message>::= <Common Header>
<request>
where:
<request>::= <RP>
<end-point-iro-xro-rro-pair-list>
[<OF>]
[<LSPA>]
[<BANDWIDTH>]
[<metric-list>]
[<IRO>]
[<LOAD-BALANCING>]
where:
<end-point-iro-xro-rro-pair-list>::=
<END-POINTS>
[<IRO>]
[<XRO>]
[<RRO-List>][<BANDWIDTH>]
[<end-point-iro-xro-rro-pair-list>]
<RRO-List>::=<RRO>[<BANDWIDTH>][<RRO-List>]
<metric-list>::=<METRIC>[<metric-list>]]]></artwork>
</figure>
</t>
<t>From <xref target="RFC6006"/> usage of <end-point-rro-pair-list> is changed to <end-point-iro-xro-rro-pair-list> in this document.</t>
<t><xref target="RFC6006"/> describes Branch Node Capability (BNC) Object which is different from the use of <IRO> and <XRO> to specify inclusion/exclusion of abstract nodes for a subset of destinations as described here.</t>
</section>
<section title="Backward Compatibility" toc="default">
<t>A legacy implementation that does not support explicit inclusion or exclusion of abstract nodes for a subset of P2MP destinations will act according to the procedures set out in <xref target="RFC5440"/>, that is it will find the P2MP Path Request message out of order with respect to the format specified in <xref target="RFC6006"/>.</t>
</section>
</section>
<section title="IANA Considerations" toc="default">
<t>There are no new IANA allocation in this document.</t>
</section>
<section title="Security Considerations" toc="default">
<t>PCEP security mechanisms as described in <xref target="RFC5440"/>, <xref target="RFC6006"/> and <xref target="PCE-P2MP-PROCEDURES"/> are applicable for this document.</t>
<t>The new explicit inclusion or exclusion of abstract nodes for a subset of P2MP destination defined in this document allow finer and more specific control of the path computed by a PCE. Such control increases the risk if a PCEP message is intercepted, modified, or spoofed because it allows the attacker to exert control over the path that the PCE will compute or to make the path computation impossible. Therefore, the security techniques described in <xref target="RFC5440"/>, <xref target="RFC6006"/> and <xref target="PCE-P2MP-PROCEDURES"/> are considered more important.</t>
<t>Note, however, that the route exclusion mechanisms also provide the operator with the ability to route around vulnerable parts of the network and may be used to increase overall network security.</t>
</section>
<section title="Manageability Considerations" toc="default">
<section title="Control of Function and Policy" toc="default">
<t>Mechanisms defined in this document do not add any new control function/policy requirements in addition to those already listed in <xref target="RFC6006"/>.</t>
</section>
<section title="Information and Data Models" toc="default">
<t>Mechanisms defined in this document do not imply any new MIB requirements in addition to those already listed in <xref target="PCE-P2MP-MIB"/>.</t>
</section>
<section title="Liveness Detection and Monitoring" toc="default">
<t>Mechanisms defined in this document do not imply any new liveness detection and monitoring requirements in addition to those already listed in <xref target="RFC6006"/>.</t>
</section>
<section title="Verify Correct Operations" toc="default">
<t>Mechanisms defined in this document do not imply any new operation verification requirements in addition to those already listed in <xref target="RFC6006"/>.</t>
</section>
<section title="Requirements On Other Protocols" toc="default">
<t>Mechanisms defined in this document do not imply any requirements on other protocols in addition to those already listed in <xref target="RFC6006"/>.</t>
</section>
<section title="Impact On Network Operations" toc="default">
<t>Mechanisms defined in this document do not have any impact on network operations in addition to those already listed in <xref target="RFC6006"/>.</t>
</section>
</section>
<section title="Acknowledgments" toc="default">
<t>We would like to thank Pradeep Shastry, Suresh babu, Quintin Zhao, Daniel King and Chen Huaimo for their useful comments and suggestions.</t>
</section>
</middle>
<back>
<references title="Normative References">
<?rfc include="reference.RFC.2119.xml" ?>
</references>
<references title="Informative References">
<?rfc include="reference.RFC.3209.xml" ?>
<?rfc include="reference.RFC.3477.xml" ?>
<?rfc include="reference.RFC.4655.xml" ?>
<?rfc include="reference.RFC.4874.xml" ?>
<?rfc include="reference.RFC.5440.xml" ?>
<?rfc include="reference.RFC.5862.xml" ?>
<?rfc include="reference.RFC.6006.xml" ?>
<!--PCE-P2MP-PROCEDURES-->
<reference anchor="PCE-P2MP-PROCEDURES">
<front>
<title>PCE-based Computation Procedure To Compute Shortest Constrained P2MP Inter-domain Traffic Engineering Label Switched Paths (draft-ietf-pce-pcep-inter-domain-p2mp-procedures-02)</title>
<author initials="Q" surname="Zhao" fullname="Zhao Q">
<organization />
</author>
<author initials="D" surname="Dhody" fullname="Dhody D">
<organization />
</author>
<author initials="Z" surname="Ali" fullname="Ali Z">
<organization />
</author>
<author initials="T" surname="Saad," fullname="Saad T">
<organization />
</author>
<author initials="S" surname="Sivabalan," fullname="Sivabalan S">
<organization />
</author>
<author initials="R" surname="Casellas" fullname="Casellas R">
<organization />
</author>
<date month="May" year="2012" />
</front>
</reference>
<!--PCE-P2MP-MIB-->
<reference anchor="PCE-P2MP-MIB">
<front>
<title>Management Information Base for the PCE Communications Protocol (PCEP) When Requesting Point-to-Multipoint Services (draft-zhao-pce-pcep-p2mp-mib-05)</title>
<author initials="Q" surname="Zhao" fullname="Zhao Q">
<organization />
</author>
<author initials="D" surname="Dhody" fullname="Dhody D">
<organization />
</author>
<author initials="U" surname="Palle" fullname="Palle U">
<organization />
</author>
<author initials="D" surname="King" fullname="King D">
<organization />
</author>
<date month="August" year="2012" />
</front>
</reference>
<!--DOMAIN-SEQ-->
<reference anchor="DOMAIN-SEQ">
<front>
<title>Standard Representation Of Domain Sequence (draft-ietf-pce-pcep-domain-sequence-01)</title>
<author initials="D" surname="Dhody" fullname="Dhruv Dhody">
<organization />
</author>
<author initials="U" surname="Palle" fullname="Udayasree Palle">
<organization />
</author>
<author initials="R" surname="Casellas" fullname="Ramon Casellas">
<organization />
</author>
<date month="July" year="2012" />
</front>
</reference>
</references>
</back>
</rfc>| PAFTECH AB 2003-2026 | 2026-04-23 20:09:09 |