--- 1/draft-ietf-mpls-p2mp-sig-requirement-03.txt 2006-02-04 17:16:29.000000000 +0100 +++ 2/draft-ietf-mpls-p2mp-sig-requirement-04.txt 2006-02-04 17:16:29.000000000 +0100 @@ -1,20 +1,19 @@ - Network Working Group Seisho Yasukawa (NTT) Internet Draft Editor Category: Informational -Expiration Date: December 2005 June 2005 +Expiration Date: June 2006 December 2005 Signaling Requirements for Point to Multipoint Traffic Engineered MPLS LSPs - + Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that @@ -34,95 +33,105 @@ Abstract This document presents a set of requirements for the establishment and maintenance of Point-to-Multipoint (P2MP) Traffic Engineered (TE) Multiprotocol Label Switching (MPLS) Label Switched Paths (LSPs). There is no intent to specify solution specific details nor application specific requirements in this document. - The requirements presented in this document are - not limited to the requirements of packet switched networks, but also + The requirements presented in this document apply equally to packet + switched networks under the control of MPLS protocols and to but also encompass the requirements of Layer two Switching (L2SC), Time - Division Multiplexing (TDM), lambda and port switching networks + Division Multiplexing (TDM), lambda, and port switching networks managed by Generalized MPLS (GMPLS) protocols. Protocol solutions developed to meet the requirements set out in this document must attempt to be equally applicable to MPLS and GMPLS. Table of Contents 1. Introduction ................................................... 3 - 1.1 Non-Objectives ............................................. 5 + 1.1 Non-Objectives ................................................ 5 2. Definitions .................................................... 6 - 2.1 Acronyms ................................................... 6 - 2.2 Terminology ................................................ 6 - 2.2.1 Terminology for Partial LSPs .......................... 7 - 2.3 Conventions ................................................ 8 - 3. Problem Statement .............................................. 8 - 3.1 Motivation ................................................. 8 - 3.2. Requirements Overview ..................................... 9 + 2.1 Acronyms ...................................................... 6 + 2.2 Terminology ................................................... 6 + 2.2.1 Terminology for Partial LSPs ................................ 7 + 2.3 Conventions ................................................... 8 + 3. Problem Statement .............................................. 9 + 3.1 Motivation .................................................... 9 + 3.2. Requirements Overview......................................... 9 4. Detailed requirements for P2MP TE extensions .................. 11 - 4.1 P2MP LSP ................................................. 11 - 4.2 P2MP explicit routing ..................................... 11 - 4.3 Explicit Path Loose Hops and Widely Scoped Abstract Nodes . 12 - 4.4 P2MP TE LSP establishment, teardown, and modification - mechanisms ................................................ 13 - 4.5 Fragmentation ............................................. 14 - 4.6 Failure Reporting and Error Recovery ...................... 14 - 4.7 Record route of P2MP TE LSP .............................. 15 - 4.8 Call Admission Control (CAC) and QoS Control mechanism - of P2MP TE LSPs ........................................... 16 - 4.9 Variation of LSP Parameters ............................... 16 - 4.10 Re-optimization of P2MP TE LSPs .......................... 16 - 4.11 Tree Remerge ............................................. 17 - 4.12 Data Duplication ......................................... 18 - 4.13 IPv4/IPv6 support ........................................ 19 - 4.14 P2MP MPLS Label .......................................... 19 - 4.15 Routing advertisement of P2MP capability ................. 19 - 4.16 Multi-access LANs ........................................ 20 - 4.17 P2MP MPLS OAM ............................................ 20 - 4.18 Scalability .............................................. 20 - 4.18.1 Absolute Limits ..................................... 21 - 4.19 Backwards Compatibility .................................. 23 - 4.20 GMPLS .................................................... 23 - 4.21 P2MP Crankback routing ................................... 24 + 4.1 P2MP LSP ..................................................... 11 + 4.2 P2MP explicit routing......................................... 11 + 4.3 Explicit Path Loose Hops and Widely Scoped Abstract Nodes .... 12 + 4.4 P2MP TE LSP establishment, teardown, and modification mechanisms + ............................................................ 13 + 4.5 Fragmentation ................................................ 14 + 4.6 Failure Reporting and Error Recovery ......................... 14 + 4.7 Record route of P2MP TE LSP .................................. 15 + 4.8 Call Admission Control (CAC) and QoS Control mechanism of + P2MP TE LSPs ............................................... 16 + 4.9 Variation of LSP Parameters .................................. 16 + 4.10 Re-optimization of P2MP TE LSPs ............................. 17 + 4.11 Merging of Tree Branches .................................... 17 + 4.12 Data Duplication ............................................ 18 + 4.13 IPv4/IPv6 support ........................................... 19 + 4.14 P2MP MPLS Label ............................................. 19 + 4.15 Advertisement of P2MP capability ............................ 19 + 4.16 Multi-access LANs ........................................... 20 + 4.17 P2MP MPLS OAM ............................................... 20 + 4.18 Scalability ................................................. 20 + 4.18.1 Absolute Limits ........................................... 21 + 4.19 Backwards Compatibility ..................................... 23 + 4.20 GMPLS ....................................................... 23 + 4.21 P2MP Crankback routing ...................................... 24 5. Security Considerations ....................................... 24 6. IANA Considerations ........................................... 25 7. Acknowledgements .............................................. 25 8. References .................................................... 25 - 8.1 Normative References ...................................... 25 - 8.2 Informational References .................................. 26 - 9. Editor's Address .............................................. 27 - 10. Authors' Addresses ........................................... 27 + 8.1 Normative References ......................................... 25 + 8.2 Informational References ..................................... 25 + 9. Editor's Address .............................................. 26 + 10. Authors' Addresses ........................................... 26 11. Intellectual Property Consideration .......................... 28 - 12. Full Copyright Statement ..................................... 29 + 12. Full Copyright Statement ..................................... 28 1. Introduction Existing MPLS Traffic Engineering (MPLS-TE) allows for strict QoS guarantees, resources optimization, and fast failure recovery, but - is limited to point-to-point (P2P) applications. Requirements have - been expressed for the provision of point-to-multipoint (P2MP) - services using traffic engineered LSPs and this clearly motivates - enhancements of the base MPLS-TE tool box in order to support P2MP - MPLS-TE LSPs. + is limited to point-to-point (P2P) LSPs. There is a desire to support + point-to-multipoint (P2MP) services using traffic engineered LSPs and + this clearly motivates enhancements of the base MPLS-TE tool box in + order to support P2MP MPLS-TE LSPs. + + A P2MP TE LSP is a TE LSP in the definitions of [RFC2702] and + [RFC3031] that has a single ingress LSR, one or more egress LSRs, and + is unidirectional. P2MP services (that deliver data from a single + source to one or more receivers) may be supported by any combination + of P2P and P2MP LSPs depending on the degree of optimization required + within the network, and such LSPs may be Traffic Engineered again + depending on the requirements of the network. Further, multipoint-to- + multipoint (MP2MP) services (that deliver data from more than one + source to one or more receivers) may be supported by a combination + of P2P and P2MP LSPs. [RFC2702] specifies requirements for traffic engineering over MPLS. - It describes traffic engineering in some detail, and those - definitions and objectives are equally applicable to traffic - engineering in a point-to-multipoint service environment. They are - not repeated here, but it is assumed that the reader is fully - familiar with them. + In Section 2, it describes traffic engineering in some detail, and + those definitions are equally applicable to traffic engineering in a + point-to-multipoint service environment. They are not repeated here, + but it is assumed that the reader is fully familiar with them. - [RFC2702] also explains how MPLS is particularly suited to traffic - engineering, and presents the following eight reasons. + Section 3.0 of [RFC2702] also explains how MPLS is particularly + suited to traffic engineering, and presents the following eight + reasons. 1. Explicit label switched paths which are not constrained by the destination based forwarding paradigm can be easily created through manual administrative action or through automated action by the underlying protocols. 2. LSPs can potentially be efficiently maintained. 3. Traffic trunks can be instantiated and mapped onto LSPs. 4. A set of attributes can be associated with traffic trunks which modulate their behavioral characteristics. 5. A set of attributes can be associated with resources which @@ -131,21 +140,21 @@ whereas classical destination only based IP forwarding permits only aggregation. 7. It is relatively easy to integrate a "constraint-based routing" framework with MPLS. 8. A good implementation of MPLS can offer significantly lower overhead than competing alternatives for Traffic Engineering. These points are equally applicable to point-to-multipoint traffic engineering. Points 1. and 7. are particularly important. Note that point 3. implies that the concept of a point-to-multipoint traffic - trunk is defined and is supported (or mapped onto) P2MP LSPs. + trunk is defined and is supported by (or mapped onto) P2MP LSPs. That is, the traffic flow for a point-to-multipoint LSP is not constrained to the path or paths that it would follow during multicast routing or shortest path destination-based routing, but can be explicitly controlled through manual or automated action. Further, the explicit paths that are used may be computed using algorithms based on a variety of constraints to produce all manner of tree shapes. For example, an explicit path may be cost-based [STEINER], shortest path, QoS-based, or may use some fair-cost QoS @@ -153,32 +162,32 @@ [RFC2702] also describes the functional capabilities required to fully support Traffic Engineering over MPLS in large networks. This document presents a set of requirements for Point-to-Multipoint (P2MP) Traffic Engineering (TE) extensions to Multiprotocol Label Switching (MPLS). It specifies functional requirements for solutions to deliver P2MP TE LSPs. Solutions that specify procedures for P2MP TE LSP setup MUST satisfy - these requirements. There is no intent to specify solution specific - details nor application specific requirements in this document. + these requirements. There is no intent to specify solution-specific + details nor application-specific requirements in this document. - The requirements presented in this document are not limited to the - requirements of packet switched networks, but also encompass the - requirements of TDM, lambda and port switching networks managed by - Generalized MPLS (GMPLS) protocols. Protocol solutions developed to - meet the requirements set out in this document MUST attempt to be + The requirements presented in this document apply equally to packet + packet switched networks under the control of MPLS protocols and to + packet switched, TDM, lambda, and port switching networks managed + by Generalized MPLS (GMPLS) protocols. Protocol solutions developed + to meet the requirements set out in this document MUST attempt to be equally applicable to MPLS and GMPLS. Existing MPLS TE mechanisms such as [RFC3209] do not support P2MP TE - LSPs so new mechanisms need to be developed. This should be achieved + LSPs so new mechanisms need to be developed. This SHOULD be achieved with maximum re-use of existing MPLS protocols. Note that there is a separation between routing and signaling in MPLS TE. In particular, the path of the MPLS TE LSP is determined by performing a constraint-based computation (such as CSPF) on a traffic engineering database (TED). The contents of the TED may be collected through a variety of mechanisms. This document focuses on requirements for establishing and maintaining P2MP MPLS TE LSPs through signaling protocols; and @@ -192,157 +201,170 @@ o A P2MP TE LSP will be set up with TE constraints and will allow efficient packet or data replication at various branching points in the network. Although replication is a data plane issue, it is the responsibility of the control plane (acting in conjunction with the path computation component) to install LSPs in the network such that replication can be performed efficiently. Note that the notion of "efficient" replication is relative and may have different meanings depending on the objectives (see section 4.2). o P2MP TE LSP setup mechanisms must include the ability to add/remove - receivers to/from an existing P2MP TE LSP. + receivers to/from the P2MP service supported by an existing P2MP TE + LSP. o Tunnel endpoints of P2MP TE LSP will be modified by adding/removing egress LSRs to/from an existing P2MP TE LSP. It is assumed that the - rate of change of leaves of a P2MP service (that is, the rate at + rate of change of leaves of a P2MP LSP (that is, the rate at which new egress LSRs join, or old egress LSRs are pruned) is "not so high" because P2MP TE LSPs are assumed to be utilized for TE applications. This issue is discussed at greater length in section 4.18.1. - o A P2MP TE LSP will be protected by fast error recovery mechanisms - to minimize disconnection of a P2MP service. And a set of - attributes of the P2MP TE LSP (e.g. bandwidth etc) will be modified - by some mechanism (e.g. Make-before-break etc) to accommodate - attribute changes to the P2MP service. These issues are discussed - in section 4.6 and 4.10. + o A P2MP TE LSP may be protected by fast error recovery mechanisms + to minimize disconnection of a P2MP service. + + o And a set of attributes of the P2MP TE LSP (e.g. bandwidth, etc.) + may be modified by some mechanism (e.g. make-before-break etc.) + to accommodate attribute changes to the P2MP service without + impacting data traffic. These issues are discussed in section 4.6 + and 4.10. + + It is not a requirement that the ingress LSR must control the + addition or removal of leaves from the P2MP tree. It is this document's objective that a solution compliant to the - requirements equips and operates these P2MP TE capabilities in a - scalable fashion. + requirements set out in this document MUST operate these P2MP + TE capabilities in a scalable fashion. 1.1 Non-Objectives For clarity, this section lists some items that are out of scope of this document. It is assumed that some information elements describing the P2MP TE LSP are known to the ingress LSR prior to LSP establishment. For example, the ingress LSRs knows the IP addresses that identify the egress LSRs of the P2MP TE LSP. The mechanisms by which the ingress LSR obtains this information is outside the scope of P2MP TE signaling and so is not included in this document. Other documents may complete the description of this function by providing automated, protocol-based ways of passing this information to the ingress LSR. - The following are non-objectives of this document. + This document does not specify any requirements for the following + functions. - Non-TE LSPs (such as per-hop, routing-based LSPs). - - Discovery of egress leaves for a P2MP LSP + - Discovery of egress leaves for a P2MP LSP. - - Hierarchical P2MP LSPs - - OAM for P2MP LSPs - - Inter-area and inter-AS P2MP TE LSPs + - Hierarchical P2MP LSPs. + - OAM for P2MP LSPs. + - Inter-area and inter-AS P2MP TE LSPs. - - Applicability of P2MP MPLS TE LSPs to service scenarios - - Specific application or application requirements + - Applicability of P2MP MPLS TE LSPs to service scenarios. + - Specific application or application requirements. - - Algorithms for computing P2MP distribution trees - - Multipoint-to-point LSPs - - Multipoint-to-multipoint LSPs - - Routing protocols - - Construction of the traffic engineering database + - Algorithms for computing P2MP distribution trees. + + - Multipoint-to-point LSPs. + - Multipoint-to-multipoint LSPs. + - Routing protocols. + - Construction of the traffic engineering database. - Distribution of the information used to construct the traffic - engineering database + engineering database. 2. Definitions 2.1 Acronyms P2P: Point-to-point P2MP: Point-to-multipoint 2.2 Terminology The reader is assumed to be familiar with the terminology in [RFC3031] and [RFC3209]. - The following terms are defined for use in the context of TE LSPs - only. + The following terms are defined for use in the context of P2MP TE + LSPs only. P2MP tree: The ordered set of LSRs and TE links that comprise the path of a P2MP TE LSP from its ingress LSR to all of its egress LSRs. ingress LSR: - The LSR that is responsible for initiating the signaling - messages that set up the P2MP TE LSP. + The LSR that is responsible for initiating the signaling messages + that set up the P2MP TE LSP. egress LSR: - One of potentially many destinations of the P2MP TE LSP. - Egress LSRs may also be referred to as leaf nodes or leaves. + One of potentially many destinations of the P2MP TE LSP. Egress + LSRs may also be referred to as leaf nodes or leaves. bud LSR: - An LSR that is an egress, but also has one or more directly + An LSR that is an egress LSR, but also has one or more directly connected downstream LSRs. branch LSR: An LSR that has more than one directly connected downstream LSR. - graft LSR: + P2MP-ID (P2ID): - An LSR that is already a member of the P2MP tree and is in - process of signaling a new sub-P2MP tree. + A unique identifier of a P2MP TE LSP, that is constant for the + whole LSP regardless of the number of branches and/or leaves. - prune LSR: + source: - An LSR that is a member of the P2MP tree and is in - process of tearing down an existing sub-P2MP tree. + The sender of traffic that is carried on a P2MP service supported + by a P2MP LSP. The sender is not necessarily the ingress LSR of + the P2MP LSP. - P2MP-ID (P2ID): + receiver: - A unique identifier of a P2MP TE LSP, that is constant for the - whole LSP regardless of the number of branches and/or leaves. + A recipient of traffic carried on a P2MP service supported by a + P2MP LSP. A receiver is not necessarily an egress LSR of the P2MP + LSP. Zero, one or more receivers may receive data through a given + egress LSR. 2.2.1 Terminology for Partial LSPs It is convenient to sub-divide P2MP trees for functional and representational reasons. A tree may be divided in two dimensions: - A division may be made along the length of the tree. For example, the tree may be split into two components each running from the - ingress LSR to a discrete set of egress LSRs + ingress LSR to a discrete set of egress LSRs. Upstream LSRs (for + example, the ingress LSR) may be members of both components. - A tree may be divided at a branch LSR (or any transit LSR) to produce a component of the tree that runs from the branch (or - transit) LSR to all downstream egress LSRs. + transit) LSR to all egress LSRs downstream of this point. These two methods of splitting the P2MP tree can be combined, so it is useful to introduce some terminology to allow the partitioned trees to be clearly described. Use the following designations: Source (ingress) LSR - S Leaf (egress) LSR - L Branch LSR - B - Transit LSR - X + Transit LSR - X (any single, arbitrary LSR that is not a source, + leaf or branch) All - A Partial (i.e. not all) - P Define a new term: Sub-LSP A segment of a P2MP TE LSP that runs from one of the LSP's LSRs to one or more of its other LSRs. @@ -352,64 +374,64 @@ S2L sub-LSP The path from the source to one specific leaf. S2PL sub-LSP The path from the source to a set of leaves. B2AL sub-LSP The path from a branch LSR to all downstream leaves. X2X sub-LSP - A component of the P2MP LSP that is a simple path with - no branches. + A component of the P2MP LSP that is a simple path thatwith + does not branches. Note that the S2AL sub-LSP is equivalent to the P2MP LSP. 2.3 Conventions 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 [RFC2119]. 3. Problem Statement 3.1 Motivation As described in section 1, Traffic Engineering and Constraint Based - Routing, including Call Admission Control(CAC), explicit source - routing and bandwidth reservation, are required to enable efficient + Routing (including Call Admission Control(CAC), explicit source + routing, and bandwidth reservation) are required to enable efficient resource usage and strict QoS guarantees. Such mechanisms also make it possible to provide services across a congested network where conventional "shortest path first" forwarding paradigms would fail. Existing MPLS TE mechanisms [RFC3209] and GMPLS TE mechanisms [RFC3473] only provide support for P2P TE LSPs. While it is possible to provide P2MP TE services using P2P TE LSPs, any such approach is potentially suboptimal since it may result in data replication at the ingress LSR, or in duplicate data traffic within the network. Hence, to provide P2MP MPLS TE services in a fully efficient manner it is necessary to specify specific requirements. These requirements - can then be used to define mechanisms for the use of existing + can then be used when defining mechanisms for the use of existing protocols and/or extensions to existing protocols and/or new protocols. 3.2. Requirements Overview This document states basic requirements for the setup of P2MP TE LSPs. The requirements apply to the signaling techniques only, and no assumptions are made about which routing protocols are run within the network, nor about how the information that is used to construct the Traffic Engineering Database (TED) is distributed. These factors are out of the scope of this document. - A P2MP TE LSP path will be computed taking into account various + A P2MP TE LSP path computation will take into account various constraints such as bandwidth, affinities, required level of protection and so on. The solution MUST allow for the computation of P2MP TE LSP paths satisfying constraints with the objective of supporting various optimization criteria such as delays, bandwidth consumption in the network, or any other combinations. This is likely to require the presence of a TED, as well as the ability to signal the explicit path of an LSP. A desired requirement is also to maximize the re-use of existing MPLS TE techniques and protocols where doing so does not adversely @@ -421,21 +443,21 @@ ... the consensus reached by the Multiprotocol Label Switching (MPLS) Working Group within the IETF to focus its efforts on "Resource Reservation Protocol (RSVP)-TE: Extensions to RSVP for Label-Switched Paths (LSP) Tunnels" (RFC 3209) as the MPLS signaling protocol for traffic engineering applications... The P2MP TE LSP setup mechanism MUST include the ability to add/remove egress LSRs to/from an existing P2MP TE LSP and MUST allow for the support of all the TE LSP management procedures already defined for P2P TE LSP. Further, when new TE LSP procedures - are developed for P2P TE LSPs equivalent or identical procedures + are developed for P2P TE LSPs, equivalent or identical procedures SHOULD be developed for P2MP TE LSPs. The computation of P2MP trees is implementation dependent and is beyond the scope of the solutions that are built with this document as a guideline. Consider the following figure. Source 1 (S1) | @@ -444,73 +466,72 @@ | | R2----E-LSR3--LSR1 LSR2---E-LSR2--Receiver 1 (R1) | : R3----E-LSR4 E-LSR5 | : | : R4 R5 Figure 1 - Figure 1 shows a single ingress (I-LSR1), and four egresses(E-LSR2, - E-LSR3, E-LSR4 and E-LSR5). I-LSR1 is attached to a traffic source - that is generating traffic for a P2MP application. Receivers R1, R2, - R3 and R4 are attached to E-LSR2, E-LSR3 and E-LSR4. + Figure 1 shows a single ingress LSR (I-LSR1), and four egress LSRs + (E-LSR2, E-LSR3, E-LSR4 and E-LSR5). I-LSR1 is attached to a traffic + source that is generating traffic for a P2MP application. Receivers + R1, R2, R3 and R4 are attached to E-LSR2, E-LSR3 and E-LSR4. The following are the objectives of P2MP LSP establishment and use. a) A P2MP tree which satisfies various constraints is - pre-determined and supplied to ingress I-LSR1. + pre-determined and details are supplied to I-LSR1. Note that no assumption is made on whether the tree is - provided to I-LSR1 or computed by I-LSR1. Note that the - solution SHOULD also allow for the support of partial path by + provided to I-LSR1 or computed by I-LSR1. The + solution SHOULD also allow for the support of a partial path by means of loose routing. Typical constraints are bandwidth requirements, resource class - affinities, fast rerouting, preemption, to mention a few of - them. There should not be any restriction on the possibility - to support the set of constraints already defined for point to - point TE LSPs. A new constraint may specify which LSRs should - be used as branch points for the P2MP LSR in order to take - into account some LSR capabilities or network constraints. + affinities, fast rerouting, preemption. There should not be any + restriction on the possibility to support the set of + constraints already defined for point to point TE LSPs. A new + constraint may specify which LSRs should be used as branch LSRs + for the P2MP LSR in order to take into account LSR capabilities + or network constraints. b) A P2MP TE LSP is set up from I-LSR1 to E-LSR2, E-LSR3 and E-LSR4 using the tree information. c) In this case, the branch LSR1 should replicate incoming packets or data and send them to E-LSR3 and E-LSR4. d) If a new receiver (R5) expresses an interest in receiving - traffic, a new tree is determined and a B2L sub-LSP from - LSR2 to E-LSR5 is grafted onto the P2MP TE LSP. LSR2 becomes a + traffic, a new tree is determined and a B2L sub-LSP from LSR2 + to E-LSR5 is grafted onto the P2MP TE LSP. LSR2 becomes a branch LSR. 4. Detailed requirements for P2MP TE extensions 4.1 P2MP LSP The P2MP TE extensions MUST be applicable to the signaling of LSPs for different switching types. For example, it MUST be possible to signal a P2MP TE LSP in any switching medium being packet or - non-packet based (including frame, cell, TDM, lambda, etc.) + non-packet based (including frame, cell, TDM, lambda, etc.). As with P2P MPLS technology [RFC3031], traffic is classified with a FEC in this extension. All packets which belong to a particular FEC and which travel from a particular node MUST follow the same P2MP tree. In order to scale to a large number of branches, P2MP TE LSPs SHOULD be identified by a unique identifier (the P2MP ID or P2ID) that is constant for the whole LSP regardless of the number of branches - and/or leaves. Therefore, the identification of the P2MP session by - its destination addresses is not adequate. + and/or leaves. 4.2 P2MP explicit routing Various optimizations in P2MP tree formation need to be applied to meet various QoS requirements and operational constraints. Some P2MP applications may request a bandwidth guaranteed P2MP tree which satisfies end-to-end delay requirements. And some operators may want to set up a cost minimum P2MP tree by specifying branch LSRs explicitly. @@ -542,32 +563,32 @@ support a mechanism that can setup this kind of bud LSR between an ingress LSR and egress LSRs. Note that this includes constrained Steiner trees that allow for the computation of a minimal cost trees with some other constraints such as a bounded delay between the source and every receiver. Another example is a CSPF (Constraint Shortest Path First) P2MP tree. By some metric (which can be set upon any specific criteria like the delay, bandwidth, a combination of those), one can calculate a shortest path P2MP tree. This P2MP tree is suitable for - carrying real time traffic. + carrying real-time traffic. The solution MUST allow the operator to make use of any tree computation technique. In the former case an efficient/optimal tree is defined as a minimal cost tree (Steiner tree) whereas in the later case it is defined as the tree that provides shortest path between the source and any receiver. To support explicit setup of any reasonable P2MP tree shape, a P2MP TE solution MUST support some form of explicit source-based control of the P2MP tree which can explicitly include particular LSRs as - branch nodes. This can be used by the ingress LSR to setup the P2MP + branch LSRs. This can be used by the ingress LSR to setup the P2MP TE LSP. For instance, a P2MP TE LSP can be simply represented as a whole tree or by its individual branches. 4.3 Explicit Path Loose Hops and Widely Scoped Abstract Nodes A P2MP tree is completely specified if all of the required branches and hops between a sender and leaf LSR are indicated. A P2MP tree is partially specified if only a subset of intermediate branches and hops are indicated. This may be achieved using loose @@ -579,58 +600,59 @@ beyond the scope of this document. Protocol solutions SHOULD include a way to specify loose hops and widely scoped abstract nodes in the explicit source-based control of the P2MP tree as defined in the previous section. Where this support is provided, protocol solutions MUST allow downstream LSRs to apply further explicit control to the P2MP tree to resolve a partially specified tree into a (more) completely specified tree. Protocol solutions MUST allow the P2MP tree to be completely - specified at the ingress where sufficient information exists to allow - the full tree to be computed and where policies along the path (such - as at domain boundaries) support full specification. + specified at the ingress LSR where sufficient information exists to + allow the full tree to be computed and where policies along the path + (such as at domain boundaries) support full specification. - In all cases, the egress nodes of the P2MP TE LSP must be fully + In all cases, the egress LSRs of the P2MP TE LSP must be fully specified either individually or through some collective identifier. Without this information, it is impossible to know to where the TE LSP should be routed. In case of a tree being computed by some downstream LSRs (e.g. the case of hops specified as loose hops), the solution MUST provide protocol mechanisms for the ingress LSR of the P2MP TE LSP to learn the full P2MP tree. Note that this information may not always be obtainable owing to policy considerations, but where part of the path remains confidential it MUST be reported through aggregation (for example, using an AS number). 4.4 P2MP TE LSP establishment, teardown, and modification mechanisms The P2MP TE solution MUST support establishment, maintenance and teardown of P2MP TE LSPs in a manner that is at least scalable in a linear way. This MUST include both the existence of very many LSPs at once, and the existence of very many destinations for a single P2MP LSP. - In addition to P2MP TE LSP establishment and teardown mechanism, it - SHOULD implement partial P2MP tree modification mechanism. + In addition to P2MP TE LSP establishment and teardown mechanisms, it + SHOULD support a partial P2MP tree modification mechanism. For the purpose of adding sub-P2MP TE LSPs to an existing P2MP TE LSP, the extensions SHOULD support a grafting mechanism. For the purpose of deleting a sub-P2MP TE LSPs from an existing P2MP TE LSP, the extensions SHOULD support a pruning mechanism. - It is RECOMMENDED that these grafting and pruning operations do not - cause any additional processing in nodes except along the path to - the grafting and pruning node and its downstream nodes. Moreover, - both grafting and pruning operations MUST not be traffic disruptive - for the traffic currently forwarded along the P2MP tree. + It is RECOMMENDED that these grafting and pruning operations cause + no additional processing in nodes that are not along the path to + the grafting or pruning node, or that are downstream of the grafting + or pruning node toward the grafted or pruned leaves. Moreover, both + grafting and pruning operations MUST NOT disrupt traffic currently + forwarded along the P2MP tree. There is no assumption that the explicitly routed P2MP LSP remains on an optimal path after several grafts and prunes have occurred. In this context, scalable refers to the signaling process for the P2MP TE LSP. The TE nature of the LSP allows that re-optimization may take place from time to time to restore the optimality of the LSP. 4.5 Fragmentation The P2MP TE solution MUST handle the situation where a single @@ -652,21 +674,21 @@ The solution to these problems SHOULD NOT rely on IP fragmentation of protocol messages and it is RECOMMENDED to rely on some protocol procedures specific to the signaling solution. In the event that fragmented IP packets containing protocol messages are received, it is NOT RECOMMENDED that they are reassembled at the receiving LSR. 4.6 Failure Reporting and Error Recovery - Failure events may cause egress nodes or sub-P2MP LSPs to become + Failure events may cause egress LSRs or sub-P2MP LSPs to become detached from the P2MP TE LSP. These events MUST be reported upstream as for a P2P LSP. The solution SHOULD provide recovery techniques such as protection and restoration allowing recovery of any impacted sub-P2MP TE LSPs. In particular, a solution MUST provide fast protection mechanisms applicable to P2MP TE LSP similar to the solutions specified in [RFC4090] for P2P TE LSPs. Note also that no assumption is made on whether backup paths for P2MP TE LSPs should or should not be shared with P2P TE LSPs backup paths. @@ -684,39 +706,39 @@ requirements, or may want to relax some requirements stated in this document. This may lead to variations in the solution. The solution SHOULD also support the ability to meet other network recovery requirements such as bandwidth protection and bounded propagation delay increase along the backup path during failure. A P2MP TE solution MUST support P2MP fast protection mechanism to handle P2MP applications sensitive to traffic disruption. - If the ingress is informed of the failure of delivery to fewer than - all of the egress nodes this SHOULD NOT cause automatic teardown of - the P2MP TE LSP. That is, while some egress nodes remain connected to - the P2MP tree it SHOULD be a matter of local policy at the ingress - whether the P2MP LSP is retained. + If the ingress LSR is informed of the failure of delivery to fewer + than all of the egress LSRs this SHOULD NOT cause automatic teardown + of the P2MP TE LSP. That is, while some egress LSRs remain connected + to the P2MP tree it SHOULD be a matter of local policy at the ingress + LSR whether the P2MP LSP is retained. - When all egress nodes downstream of a branch node have become - disconnected from the P2MP tree, and the some branch node is unable + When all egress LSRs downstream of a branch LSR have become + disconnected from the P2MP tree, and some branch LSR is unable to restore connectivity to any of them by means of some recovery or - protection mechanisms, the branch node MAY remove itself from the + protection mechanisms, the branch LSR MAY remove itself from the P2MP tree provided that it is not also an egress LSR (that is, a bud). Since the faults that severed the various downstream egress - nodes from the P2MP tree may be disparate, the branch node MUST + LSRs from the P2MP tree may be disparate, the branch LSR MUST report all such errors to its upstream neighbor. An upstream LSR or - the ingress node can then decide to re-compute the path to those - particular egress nodes, around the failure point. + the ingress LSR can then decide to re-compute the path to those + particular egress LSRs, around the failure point. Solutions MAY include the facility for transit LSRs and particularly - branch nodes to recompute sub-P2MP trees to restore them after + branch LSRs to recompute sub-P2MP trees to restore them after failures. In the event of successful repair, error notifications SHOULD NOT be reported to upstream nodes, but the new paths are reported if route recording is in use. Crankback requirements are discussed in Section 4.21. 4.7 Record route of P2MP TE LSP Being able to identify the established topology of P2MP TE LSP is very important for various purposes such as management and operation of some local recovery mechanisms like Fast Reroute [RFC4090]. A @@ -740,106 +763,106 @@ P2MP TE LSPs P2MP TE LSPs may share network resource with P2P TE LSPs. Therefore it is important to use CAC and QoS in the same way as P2P TE LSPs for easy and scalable operation. P2MP TE solutions MUST support both resource sharing and exclusive resource utilization to facilitate co-existence with other LSPs to the same destination(s). - P2MP TE solution MUST be applicable to DiffServ-enabled networks + P2MP TE solutions MUST be applicable to DiffServ-enabled networks that can provide consistent QoS control in P2MP LSP traffic. Any solution SHOULD also satisfy the DS-TE requirements [RFC3564] and interoperate smoothly with current P2P DS-TE protocol specifications. Note that this requirement document does not make any assumption on the type of bandwidth pool used for P2MP TE LSPs which can either be shared with P2P TE LSP or be dedicated for P2MP use. 4.9 Variation of LSP Parameters Certain parameters (such as priority and bandwidth) are associated with an LSP. The parameters are installed by the signaling exchanges associated with establishing and maintaining the LSP. Any solution MUST NOT allow for variance of these parameters within a single P2MP LSP. That is: - - No attributes set and signaled by the ingress of a P2MP LSP may + - No attributes set and signaled by the ingress LSR of a P2MP LSP may be varied by downstream LSRs. - There MUST be homogeneous QoS from the root to all leaves of a single P2MP LSP. - Variation of parameters may be allowed so long as it applies to the - whole LSP from ingress to all egresses. + Changing the parameters for the whole tree MAY be supported, but the + change MUST apply to the whole tree from ingress LSR to all egress + LSRs. 4.10 Re-optimization of P2MP TE LSPs The detection of a more optimal path (for example, one with a lower overall cost) is an example of a situation where P2MP TE LSP re-routing may be required. While re-routing is in progress, an important requirement is avoiding double bandwidth reservation (over the common parts between the old and new LSP) thorough the use of resource sharing. Make-before-break MUST be supported for a P2MP TE LSP to ensure that there is minimal traffic disruption when the P2MP TE LSP is re-routed. - It is possible to achieve make-before-break that only applies to a - sub-P2MP tree without impacting the data on all of the other parts - of the P2MP tree. + Make-before-break that only applies to a sub-P2MP tree without + impacting the data on all of the other parts of the P2MP tree MUST be + supported. The solution SHOULD allow for make-before-break re-optimization of any subdivision of the P2MP LSP (S2PL sub-LSP, S2X sub-LSP, S2L sub-LSP, X2AL sub-LSP, B2PL sub-LSP, X2AL sub-LSP, or B2AL tree). Further it SHOULD do so minimizing the signaling impact on the rest of the P2MP LSP, and without affecting the ability of the management plane to manage the LSP. The solution SHOULD also provide the ability for the ingress LSR to - have a strict control on the re-optimization process. The ingress + have strict control over the re-optimization process. The ingress LSR SHOULD be able to limit all re-optimization to be source-initiated. Where sub-LSP re-optimization is allowed by the ingress LSR, such re-optimization MAY be initiated by a downstream LSR that is the root of the sub-LSP that is to be re-optimized. Sub-LSP re-optimization initiated by a downstream LSR MUST be carried out - with the same regard to minimizing the hit on active traffic as + with the same regard to minimizing the impact on active traffic as was described above for other re-optimization. -4.11 Tree Remerge +4.11 Merging of Tree Branches It is possible for a single transit LSR to receive multiple signaling messages for the same P2MP LSP but for different sets of destinations. These messages may be received from the same or different upstream nodes and may need to be passed on to the same or different downstream nodes. This situation may arise as the result of the signaling solution definition or implementation options within the signaling solution. Further, it may happen during make-before-break reoptimization - (section 4.10), or as a result of signaling message fragmentation - (section 4.5). + (section 4.10). It is even possible that it is necessary to construct distinct upstream branches in order to achieve the correct label choices in certain switching technologies managed by GMPLS (for example, photonic cross-connects where the selection of a particular lambda for the downstream branches is only available on different upstream switches). - The solution MUST support the case where of multiple signaling + The solution MUST support the case where multiple signaling messages for the same P2MP LSP are received at a single transit LSR and refer to the same upstream interface. In this case the result of the protocol procedures SHOULD be a single data flow on the upstream interface. The solution SHOULD support the case where multiple signaling messages for the same P2MP LSP are received at a single transit LSR and refer to different upstream interfaces, and where each signaling message results in the use of different downstream interfaces. This case represents data flows that cross at the LSR but which do not @@ -855,29 +878,30 @@ An alternative to supporting this last case is for the signaling protocol to indicate an error such that the merge may be resolved by the upstream LSRs. 4.12 Data Duplication Data duplication refers to the receipt by any recipient of duplicate instances of the data. In a packet environment this means the receipt of duplicate packets. Although small-scale packet duplication - should be a benign (if inefficient) situation, certain existing and - deployed applications will not tolerate packet duplication. Long-term + (that is, a few packets over a relatively short period of time) + should be a harmless (if inefficient) situation, certain existing and + deployed applications will not tolerate packet duplication. Sustained packet duplication is, at best, a waste of network and processing resources, and at worst may cause congestion and the inability to process the data correctly. - In a non-packet environment data duplication means the duplication in - time of some part of the signal that may lead to the replication of - data or to the scrambling of data. + In a non-packet environment data duplication means the duplication of + some part of the signal that may lead to the replication of data or + to the scrambling of data. Data duplication may legitimately arise in various scenarios including re-optimization of active LSPs as described in the previous section, and protection of LSPs. Thus, it is impractical to regulate against data duplication in this document. Instead, the solution: - SHOULD limit to bounded transitory conditions the cases where network bandwidth is wasted by the existence of duplicate delivery @@ -893,79 +917,80 @@ 4.14 P2MP MPLS Label A P2MP TE solution MUST allow the continued use of existing techniques to establish P2P LSPs (TE and otherwise) within the same network, and MUST allow the co-existence of P2P LSPs within the same network as P2MP TE LSPs. A P2MP TE solution MUST be specified in such a way that it allows P2MP and P2P TE LSPs to be signaled on the same interface. -4.15 Routing advertisement of P2MP capability +4.15 Advertisement of P2MP capability Several high-level requirements have been identified to determine the capabilities of LSRs within a P2MP network. The aim of such information is to facilitate the computation of P2MP trees using TE constraints within a network that contains LSRs that do not all have the same capabilities levels with respect to P2MP signaling and data forwarding. These capabilities include, but are not limited to: - - the ability of an LSR to support branching. - - the ability of an LSR to act as an egress and a branch for the same - LSP. - - the ability of an LSR to support P2MP MPLS-TE signaling. + - The ability of an LSR to support branching. + - The ability of an LSR to act as an egress LSR and a branch LSR for + the same LSP. + - The ability of an LSR to support P2MP MPLS-TE signaling. 4.16 Multi-access LANs P2MP MPLS TE may be used to traverse network segments that are provided by multi-access media such as Ethernet. In these cases, it is also possible that the entry point to the network segment is a - branch point of the P2MP LSP. + branch LSR of the P2MP LSP. Two options clearly exist: - - the branch point replicates the data and transmits multiple copies + - the branch LSR replicates the data and transmits multiple copies onto the segment - - the branch point sends a single copy of the data to the segment - and relies on the exit points to discriminate the reception of - the data. + - the branch LSR sends a single copy of the data to the segment + and relies on the exit points to determine whether to receive and + forward the data. The first option has a significant data plane scaling issue since all replicated data must be sent through the same port and carried on the same segment. Thus, a solution SHOULD provide a mechanism for a - branch node to send a single copy of the data onto a multi-access + branch LSR to send a single copy of the data onto a multi-access network and reach multiple (adjacent) downstream nodes. The second option may have control plane scaling issues. 4.17 P2MP MPLS OAM - The MPLS and GMPLS MIB modules will be enhanced to provide P2MP TE + The MPLS and GMPLS MIB modules MUST be enhanced to provide P2MP TE LSP management in line with whatever signaling solutions are developed. In order to facilitate correct management, P2MP TE LSPs MUST have unique identifiers since otherwise it is impossible to determine which LSP is being managed. Further discussions of OAM are out of scope for this document. See [P2MP-OAM] for more details. 4.18 Scalability Scalability is a key requirement in P2MP MPLS systems. Solutions MUST be designed to scale well with an increase in the number of any of the following: - the number of recipients - - the number of branch points + - the number of egress LSRs + - the number of branch LSRs - the number of branches. Both scalability of control plane operation (setup, maintenance, modification and teardown) MUST be considered. Key considerations MUST include: - the amount of refresh processing associated with maintaining a P2MP TE LSP. - the amount of protocol state that must be maintained by ingress and transit LSRs along a P2MP tree. @@ -986,94 +1011,96 @@ existing P2MP LSP. It is expected that the applicability of each solution will be evaluated with regards to the aforementioned scalability criteria. 4.18.1 Absolute Limits In order to achieve the best solution for the problem space it is helpful to clarify the boundaries for P2MP TE LSPs. - - Number of recipients. + - Number of egress LSRs. A scaling bound is placed on the solution mechanism such that a P2MP TE LSP MUST reduce to similar scaling properties as a P2P LSP - when the number of recipients reduces to one. + when the number of egress LSRs reduces to one. That is, + establishing a P2MP TE LSP to a single egress LSR should cost + approximately as much as establishing a P2P LSP. It is important to classify the issues of scaling within the context of Traffic Engineering. It is anticipated that the initial deployments of P2MP TE LSPs will be limited to a maximum of around - a hundred recipients, but that medium term deployments may increase - this to several hundred, and that future deployments may require - significantly larger numbers. + a hundred egress LSRs, but that within five years deployments may + increase this to several hundred, and that future deployments may + require significantly larger numbers. An acceptable upper bound for a solution, therefore, is one that - scales linearly with the number of recipients. It is expected that + scales linearly with the number of egress LSRs. It is expected that solutions will scale better than linearly. Solutions that scale worse than linear (that is, exponential or - polynomial) are not acceptable whatever the number of recipients + polynomial) are not acceptable whatever the number of egress LSRs they could support. - - Number of branch points. + - Number of branch LSRs. Solutions MUST support all possibilities from one extreme of a - single branch point that forks to all leaves on a separate branch, - to the greatest number of branch points which is (n-1) for n - recipients. Assumptions MUST NOT be made in the solution regarding - which topology is more common, and the solution MUST be designed - to ensure scalability in all topologies. + single branch LSR that forks to all leaves on a separate branch, + to the greatest number of branch LSRs which is (n-1) for n egress + LSRs. Assumptions MUST NOT be made in the solution regarding which + topology is more common, and the solution MUST be designed to + ensure scalability in all topologies. - Dynamics of P2MP tree. - Recall that the mechanisms for determining which recipients should - be added to an LSP, and for adding and removing recipients from + Recall that the mechanisms for determining which egress LSRs should + be added to an LSP, and for adding and removing egress LSRs from that group are out of the scope of this document. Nevertheless, it is useful to understand the expected rates of arrival and - departure of recipients since this can impact the selection of + departure of egress LSRs since this can impact the selection of solution techniques. - Again, it must be recalled that this document is limited to - Traffic Engineering, and in this model the rate of change of LSP - egresses may be expected to be lower than the rate of change of + Again, it must be recalled that this document is limited to Traffic + Engineering, and in this model the rate of change of LSP egress + LSRs may be expected to be lower than the rate of change of recipients in an IP multicast group. - Although the absolute number of recipients coming and going is the + Although the absolute number of egress LSRs coming and going is the important element for determining the scalability of a solution, it may be noted that a percentage may be a more comprehensible - measure but that this is not as significant for LSPs with a small + measure, but that this is not as significant for LSPs with a small number of recipients. A working figure for an established P2MP TE LSP is less than 10% churn per day. That is, a relatively slow rate of churn. We could say that a P2MP LSP would be shared by multiple multicast groups and so the dynamics of the P2MP LSP would be relatively small. - Solutions MUST optimize around such relatively low rates of change - and are NOT REQUIRED to optimize for significantly higher rates - of change. + Solutions MUST optimize for such relatively low rates of change and + are not required to optimize for significantly higher rates of + change. - Rate of change within the network. It is also important to understand the scaling with regard to - changes within the network. That is, one of the features of a - P2MP TE LSP is that it can be robust or protected against network + changes within the network. That is, one of the features of a P2MP + TE LSP is that it can be robust or protected against network failures, and can be re-optimized to take advantage of newly available network resources. It is more important that a solution be optimized for scaling with - respect to recovery and re-optimization of the LSP, than for change - in the recipients, because P2MP is used as a TE tool. + respect to recovery and re-optimization of the LSP than for change + in the egress LSRs, because P2MP is used as a TE tool. - The solution MUST follow this distinction. + The solution MUST follow this distinction and optimize accordingly. 4.19 Backwards Compatibility It SHOULD be an aim of any P2MP solution to offer as much backward compatibility as possible. An ideal which is probably impossible to achieve would be to offer P2MP services across legacy MPLS networks without any change to any LSR in the network. If this ideal cannot be achieved, the aim SHOULD be to use legacy nodes as both transit non-branch LSRs and egress LSRs. @@ -1092,37 +1119,40 @@ The requirement for P2MP services for non-packet switch interfaces is similar to that for Packet-Switch Capable (PSC) interfaces. Therefore, it is a requirement that reasonable attempts must be made to make all the features/mechanisms (and protocol extensions) that will be defined to provide MPLS P2MP TE LSPs equally applicable to P2MP PSC and non-PSC TE-LSPs. If the requirements of non-PSC networks over-complicate the PSC solution a decision may be taken to separate the solutions. Solutions for MPLS P2MP TE-LSPs when applied to GMPLS P2MP PSC or - non-PSC TE-LSPs MUST be backward and forward compatible with the - other features of GMPLS including: + non-PSC TE-LSPs MUST be compatible with the other features of GMPLS + including: - - control and data plane separation (IF_ID RSVP_HOP and IF_ID - ERROR_SPEC), - - full support of numbered and unnumbered TE links (see [RFC 3477] - and [GMPLS-ROUTE]), - - use of the GENERALIZED_LABEL_REQUEST, the GENERALIZED_LABEL (C-Type - 2 and 3), the SUGGESTED_LABEL and the RECOVERY_LABEL, in - conjunction with the LABEL_SET and the ACCEPTABLE_LABEL_SET object, - - processing of the ADMIN_STATUS object, - - processing of the PROTECTION object, - - support of Explicit Label Control, - - processing of the Path_State_Removed Flag, + - control and data plane separation, + - full support of numbered and unnumbered TE links, + - use of the arbitrary labels and labels for specific technologies, + as well as negotiation of labels where necessary to support limited + label processing and swapping capabilities, + - the ability to apply external control to the labels selected on + each hop of the LSP, and to control the next hop + label/port/interface for data after it reaches the egress LSR, + - support for graceful and alarm-free enablement and termination of + LSPs, + - full support for protection including link level protection, + end-to-end protection and segment protection, + - the ability to teardown an LSP from a downstream LSR, in particular + from the egress LSR, - handling of Graceful Deletion procedures, - - E2E and Segment Recovery procedures, - - support of Graceful Restart. + - support for failure and restart or reconnection of the control + plane without any disruption of the data plane. In addition, since non-PSC TE-LSPs may have to be processed in environments where the "P2MP capability" could be limited, specific constraints may also apply during the P2MP TE Path computation. Being technology specific, these constraints are outside the scope of this document. However, technology independent constraints (i.e. constraints that are applicable independently of the LSP class) SHOULD be allowed during P2MP TE LSP message processing. It has to be emphasized that path computation and management techniques shall be as close as possible to those being used for @@ -1134,134 +1164,100 @@ [CRANKBACK]. In particular, they SHOULD provide sufficient information to a branch LSR from downstream LSRs to allow the branch LSR to re-route a sub-LSP around any failures or problems in the network. 5. Security Considerations This requirements document does not define any protocol extensions and does not, therefore, make any changes to any security models. + It is a requirement that any P2MP solution developed to meet some or + all of the requirements expressed in this document MUST include + mechanisms to enable the secure establishment and management of P2MP + MPLS-TE LSPs. This includes, but is not limited to: + - mechanisms to ensure that the ingress LSR of a P2MP LSP is + identified + - mechanisms to ensure that communicating signaling entities can + verify each other's identities + - mechanisms to ensure that control plane messages are protected + against spoofing and tampering + - mechanisms to ensure that unauthorized leaves or branches are not + added to the P2MP LSP + - mechanisms to protect signaling messages from snooping. + It should be noted that P2MP signaling mechanisms built on P2P RSVP-TE signaling are likely to inherit all of the security techniques and problems associated with RSVP-TE. These problems may be exacerbated in P2MP situations where security relationships may - need to maintained between an ingress and multiple egresses. Such - issues are similar to security issues for IP multicast. + need to maintained between an ingress LSR and multiple egress LSRs. + Such issues are similar to security issues for IP multicast. It is a requirement that documents offering solutions for P2MP LSPs MUST have detailed security sections. 6. IANA Considerations This informational draft does not introduce any new encodings or code points. It requires no action from IANA. 7. Acknowledgements The authors would like to thank George Swallow, Ichiro Inoue, Dean Cheng, Lou Berger and Eric Rosen for their review and suggestions. Thanks to Loa Andersson for his help resolving the final issues in - this document. + this document and to Harald Alvestrand for a thorough GenArt review. 8. References 8.1 Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. - [RFC2205] Braden, R., Zhang, L., Berson, S., Herzog, S. and - S. Jamin, "Resource ReSerVation Protocol (RSVP) - - Version 1, Functional Specification", RFC 2205, - September 1997. - - [RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z. - and W. Weiss, "An Architecture for Differentiated - Services", RFC 2475, December 1998. - - [RFC2597] Heinanen, J., Baker, F., Weiss, W. and J. Wroclawski, - "Assured Forwarding PHB Group", RFC 2597, June 1999. - [RFC2702] D. Awduche, J. Malcolm, J. Agogbua, M. O'Dell, J. McManus, "Requirements for Traffic Engineering Over MPLS", RFC2702, September 1999. [RFC3031] Rosen, E., Viswanathan, A. and R. Callon, "Multiprotocol Label Switching Architecture", RFC 3031, January 2001. [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V. and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, December 2001. - [RFC3246] Davie, B., Charny, A., Bennet, J.C.R., Benson, K., Le - Boudec, J.Y., Davari, S., Courtney, W., Firioiu, V. and - D. Stiliadis, "An Expedited Forwarding PHB (Per-Hop - Behavior)", RFC 3246, March 2002. - - [RFC3667] Bradner, S., "IETF Rights in Contributions", BCP 78, - RFC 3667, February 2004. - - [RFC3668] Bradner, S., Ed., "Intellectual Property Rights in IETF - Technology", BCP 79, RFC 3668, February 2004. - 8.2 Informational References - [RFC3471] Berger, L., Editor, "Generalized Multi-Protocol Label - Switching (GMPLS) Signaling Functional Description", - RFC 3471, January 2003. - [RFC3473] Berger, L., Editor, "Generalized Multi-Protocol Label Switching (GMPLS) Signaling - Resource ReserVation Protocol-Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. - [RFC3477] K. Kompella, Y. Rekhter, "Signalling Unnumbered Links - in Resource ReSerVation Protocol -Traffic Engineering - (RSVP-TE)", RFC3477, January 2003. - [RFC3564] F. Le Faucheur, W. Lai, "Requirements for Support of Differentiated Services-aware MPLS Traffic Engineering", RFC 3564, July 2003. - [RFC3630] D. Katz, D. Yeung, K. Kompella, "Traffic Engineering - Extensions to OSPF Version 2", RFC 3630, September - 2003. - [RFC4090] P. Pan, G. Swallow, A. Atlas, "Fast Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090, May 2005. - [GMPLS-ROUTE] K. Kompella, Y. Rekhter, Editor, "Routing Extensions - in Support of Generalized Multi-Protocol Label - Switching", draft-ietf-ccamp-gmpls-routing, work in - progress. - [STEINER] H. Salama, et al., "Evaluation of Multicast Routing Algorithm for Real-Time Communication on High-Speed Networks," IEEE Journal on Selected Area in Communications, pp.332-345, 1997. - [IS-IS-TE] Henk Smit, Tony Li, "Intermediate System to - Intermediate System (IS-IS) Extensions for Traffic - Engineering (TE)", RFC 3784, June 2004. - [CRANKBACK] A. Farrel, A. Satyanarayana, A. Iwata, N. Fujita, G. Ash, S. Marshall, "Crankback Signaling Extensions for MPLS Signaling", draft-ietf-ccamp-crankback, work in progress. - [LSP-HIER] K. Kompella, Y. Rekhter, "LSP Hierarchy with - Generalized MPLS TE", - draft-ietf-mpls-lsp-hierarchy, work in progress. - [P2MP-OAM] S. Yasukawa, A. Farrel, D. King, and T. Nadeau, "OAM Requirements for Point-to-Multipoint MPLS Networks", draft-yasukawa-mpls-p2mp-oam-reqs, work in progress. 9. Editor's Address Seisho Yasukawa NTT Corporation 9-11, Midori-Cho 3-Chome Musashino-Shi, Tokyo 180-8585,