PCE Working Group U. Palle Internet-Draft D. Dhody Intended status: Standards Track Huawei Technologies Expires: August 18, 2014 Y. Tanaka Y. Kamite NTT Communications February 14, 2014 Path Computation Element (PCE) Protocol Extensions for Stateful PCE usage for Point-to-Multipoint Traffic Engineering Label Switched Paths draft-palle-pce-stateful-pce-p2mp-02 Abstract The Path Computation Element (PCE) has been identified as an appropriate technology for the determination of the paths of point- to-multipoint (P2MP) TE LSPs. [I-D.ietf-pce-stateful-pce-app] presents several use cases, demonstrating scenarios that benefit from the deployment of a stateful PCE. [I-D.ietf-pce-stateful-pce] provides the fundamental PCE communication Protocol (PCEP) extensions needed to support stateful PCE functions. This memo provides extensions required for PCEP so as to enable the usage of a stateful PCE capability in supporting point-to-multipoint (P2MP) TE LSPs. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on August 18, 2014. Copyright Notice Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved. Palle, et al. Expires August 18, 2014 [Page 1] Internet-Draft STATEFUL-P2MP February 2014 This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Supporting P2MP TE LSP for Stateful PCE . . . . . . . . . . . 4 3.1. Motivation . . . . . . . . . . . . . . . . . . . . . . . 4 3.2. Objectives . . . . . . . . . . . . . . . . . . . . . . . 4 4. Functions to Support P2MP TE LSPs for Stateful PCEs . . . . . 4 5. Architectural Overview of Protocol Extensions . . . . . . . . 5 5.1. Extension of PCEP Messages . . . . . . . . . . . . . . . 5 5.2. Capability Advertisement . . . . . . . . . . . . . . . . 5 5.3. State Synchronization . . . . . . . . . . . . . . . . . . 6 5.4. LSP Delegation . . . . . . . . . . . . . . . . . . . . . 6 5.5. LSP Operations . . . . . . . . . . . . . . . . . . . . . 6 5.5.1. Passive Stateful PCE . . . . . . . . . . . . . . . . 6 5.5.2. Active Stateful PCE . . . . . . . . . . . . . . . . . 6 6. PCEP Object Extensions . . . . . . . . . . . . . . . . . . . 6 6.1. Extension of LSP Object . . . . . . . . . . . . . . . . . 6 6.2. P2MP-LSP-IDENTIFIER TLV . . . . . . . . . . . . . . . . . 7 6.3. S2L Object . . . . . . . . . . . . . . . . . . . . . . . 10 7. PCEP Message Extensions . . . . . . . . . . . . . . . . . . . 10 7.1. The PCRpt Message . . . . . . . . . . . . . . . . . . . . 11 7.2. The PCUpd Message . . . . . . . . . . . . . . . . . . . . 12 7.3. Example . . . . . . . . . . . . . . . . . . . . . . . . . 13 7.3.1. P2MP TE LSP Update Request . . . . . . . . . . . . . 13 7.3.2. P2MP TE LSP Report . . . . . . . . . . . . . . . . . 14 7.4. Report and Update Message Fragmentation . . . . . . . . . 15 7.4.1. Report Fragmentation Procedure . . . . . . . . . . . 15 7.4.2. Update Fragmentation Procedure . . . . . . . . . . . 15 8. Non-Support of P2MP TE LSPs for Stateful PCE . . . . . . . . 16 9. Security Considerations . . . . . . . . . . . . . . . . . . . 16 10. Manageability Considerations . . . . . . . . . . . . . . . . 16 10.1. Control of Function and Policy . . . . . . . . . . . . . 16 10.2. Information and Data Models . . . . . . . . . . . . . . 16 10.3. Liveness Detection and Monitoring . . . . . . . . . . . 16 10.4. Verify Correct Operations . . . . . . . . . . . . . . . 16 10.5. Requirements On Other Protocols . . . . . . . . . . . . 16 Palle, et al. Expires August 18, 2014 [Page 2] Internet-Draft STATEFUL-P2MP February 2014 10.6. Impact On Network Operations . . . . . . . . . . . . . . 17 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 11.1. Extension of LSP Object . . . . . . . . . . . . . . . . 17 11.2. Extension of PCEP-Error Object . . . . . . . . . . . . . 17 11.3. PCEP TLV Type Indicators . . . . . . . . . . . . . . . . 18 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 18 13.1. Normative References . . . . . . . . . . . . . . . . . . 18 13.2. Informative References . . . . . . . . . . . . . . . . . 18 1. Introduction As per [RFC4655], the Path Computation Element (PCE) is an entity that is capable of computing a network path or route based on a network graph, and applying computational constraints. A Path Computation Client (PCC) may make requests to a PCE for paths to be computed. [RFC4857] describes how to set up point-to-multipoint (P2MP) Traffic Engineering Label Switched Paths (TE LSPs) for use in Multiprotocol Label Switching (MPLS) and Generalized MPLS (GMPLS) networks. The PCE has been identified as a suitable application for the computation of paths for P2MP TE LSPs ([RFC5671]). The PCEP is designed as a communication protocol between PCCs and PCEs for point-to-point (P2P) path computations and is defined in [RFC5440]. The extensions of PCEP to request path computation for P2MP TE LSPs are described in [RFC6006]. Stateful PCEs are shown to be helpful in many application scenarios, in both MPLS and GMPLS networks, as illustrated in [I-D.ietf-pce-stateful-pce-app]. These scenarios apply equally to P2P and P2MP TE LSPs. [I-D.ietf-pce-stateful-pce]provides the fundamental extensions needed for stateful PCE to support general functionality for P2P TE LSP. Complementarily, this document focuses on the extensions that are necessary in order for the deployment of stateful PCEs to support P2MP TE LSPs. 1.1. Requirements Language 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]. Palle, et al. Expires August 18, 2014 [Page 3] Internet-Draft STATEFUL-P2MP February 2014 2. Terminology Terminology used in this document is same as terminology used in [I-D.ietf-pce-stateful-pce]and [RFC6006]. 3. Supporting P2MP TE LSP for Stateful PCE 3.1. Motivation [I-D.ietf-pce-stateful-pce-app]presents several use cases, demonstrating scenarios that benefit from the deployment of a stateful PCE including optimization, recovery, etc. [I-D.ietf-pce-stateful-pce]defines the extensions to PCEP for P2P TE LSPs in applying these scenarios. But these scenarios apply equally to P2MP TE LSPs as well. In addition to that, the stateful nature of a PCE simplifies the information conveyed in PCEP messages since it is possible to refer to the LSPs via PLSP-ID. For P2MP this is an added advantage, where the size of message is much larger. Incase of stateless PCE, a modification of P2MP tree requires encoding of all leaves along with the paths in PCReq message, but using a stateful PCE with P2MP capability, the PCEP message can be used to convey only the modifications (the other information can be retrieved from the P2MP LSP identifier). 3.2. Objectives The objectives for the protocol extensions to support P2MP TE LSP for stateful PCE are same as the objectives described in section 3.2 of [I-D.ietf-pce-stateful-pce]. 4. Functions to Support P2MP TE LSPs for Stateful PCEs [I-D.ietf-pce-stateful-pce]specifies new functions to support a stateful PCE. It also specifies that a function can be initiated either from a PCC towards a PCE (C-E) or from a PCE towards a PCC (E-C). This document extends these functions to support P2MP TE LSPs. Capability Advertisement (E-C,C-E): both the PCC and the PCE must announce during PCEP session establishment that they support PCEP Stateful PCE extensions for P2MP using mechanisms defined in [I-D.ietf-pce-stateful-pce]and [RFC6006]. LSP State Synchronization (C-E): after the session between the PCC and a stateful PCE with P2MP capability is initialized, the PCE Palle, et al. Expires August 18, 2014 [Page 4] Internet-Draft STATEFUL-P2MP February 2014 must learn the state of a PCC's P2MP TE LSPs before it can perform path computations or update LSP attributes in a PCC. LSP Update Request (E-C): a stateful PCE with P2MP capability requests modification of attributes on a PCC's P2MP TE LSP. LSP State Report (C-E): a PCC sends an LSP state report to a PCE whenever the state of a P2MP TE LSP changes. LSP Control Delegation (C-E,E-C): a PCC grants to a PCE the right to update LSP attributes on one or more P2MP TE LSPs; the PCE becomes the authoritative source of the LSP's attributes as long as the delegation is in effect (See Section 5.5 of [I-D.ietf-pce-stateful-pce]); the PCC may withdraw the delegation or the PCE may give up the delegation at any time. [I-D.sivabalan-pce-disco-stateful]and [RFC6006]defines the IGP extensions needed to support autodiscovery of stateful PCEs with P2MP capability. 5. Architectural Overview of Protocol Extensions 5.1. Extension of PCEP Messages New PCEP messages are defined in [I-D.ietf-pce-stateful-pce]to support stateful PCE for P2P TE LSPs. In this document these messages are extended to support P2MP TE LSPs. Path Computation State Report (PCRpt): Each P2MP TE LSP State Report in a PCRpt message can contain actual P2MP TE LSP path attributes, LSP status, etc. An LSP State Report carried on a PCRpt message is also used in delegation or revocation of control of a P2MP TE LSP to/from a PCE. The extension of PCRpt message is described in Section 7.1. Path Computation Update Request (PCUpd): Each P2MP TE LSP Update Request in a PCUpd message MUST contain all LSP parameters that a PCE wishes to set for a given P2MP TE LSP. An LSP Update Request carried on a PCUpd message is also used to return LSP delegations if at any point PCE no longer desires control of a P2MP TE LSP. The PCUpd message is described in Section 7.2. 5.2. Capability Advertisement During PCEP Initialization Phase, as per Section 7.1.1 of [I-D.ietf-pce-stateful-pce], PCEP speakers advertises Stateful capability via Stateful PCE Capability TLV in open message and as per Section 3.1 of [RFC6006], PCE advertises P2MP capability via IGP Palle, et al. Expires August 18, 2014 [Page 5] Internet-Draft STATEFUL-P2MP February 2014 discovery or a P2MP capable TLV in open message. These mechanism when used together indicates a stateful PCE with P2MP capability. 5.3. State Synchronization State Synchronization operations described in Section 5.4 of [I-D.ietf-pce-stateful-pce]are applicable for P2MP TE LSPs as well. 5.4. LSP Delegation LSP delegation operations described in Section 5.5 of [I-D.ietf-pce-stateful-pce]are applicable for P2MP TE LSPs as well. 5.5. LSP Operations 5.5.1. Passive Stateful PCE LSP operations for passive stateful PCE described in Section 5.6.1 of [I-D.ietf-pce-stateful-pce]are applicable for P2MP TE LSPs as well. The Path Computation Request and Response message format for P2MP TE LSPs is as per Section 3.4 and Section 3.5 of [RFC6006]respectively. [Editor's Note: The Request and Response message should support LSP object, so that it is possible to refer to a LSP with a unique identifier and simplify the PCEP message exchange. for example, incase of modification of one leaf in a P2MP tree, there should be no need to carry the full P2MP tree in PCReq message.] 5.5.2. Active Stateful PCE LSP operations for active stateful PCE described in Section 5.6.2 of [I-D.ietf-pce-stateful-pce]are applicable for P2MP TE LSPs as well. 6. PCEP Object Extensions The PCEP TLV defined in this document is compliant with the PCEP TLV format defined in [RFC5440]. 6.1. Extension of LSP Object LSP Object is defined in Section 7.3 of [I-D.ietf-pce-stateful-pce]. It specifies PLSP-ID to uniquely identify an LSP that is constant for the life time of a PCEP session. Similarly for P2MP tunnel, PLSP-ID identify a P2MP TE LSP uniquely. This document adds the following flags to the LSP Object: Palle, et al. Expires August 18, 2014 [Page 6] Internet-Draft STATEFUL-P2MP February 2014 N (P2MP bit): If the bit is set to 1, it specifies the message is for P2MP TE LSP which MUST be set in PCRpt or PCUpd message for a P2MP TE LSP. F (Fragmentation bit): If the bit is set to 1, it specifies the message is fragmented. If P2MP bit is set, the following P2MP-LSP-IDENTIFIER TLV MUST be present in LSP object. 6.2. P2MP-LSP-IDENTIFIER TLV The P2MP LSP Identifier TLV MUST be included in the LSP object in PCRpt message for RSVP-signaled P2MP TE LSPs. If the TLV is missing, the PCE will generate an error with error-type 6 (mandatory object missing) and error-value TBD (12) (P2MP-LSP-IDENTIFIERS TLV missing) and close the PCEP session. The P2MP LSP Identifier TLV MAY be included in the LSP object in PCUpd message for RSVP-signaled P2MP TE LSPs. The special value of all zeros for this TLV is used to refer to all paths pertaining to a particular PLSP-ID. There are two P2MP LSP Identifier TLVs, one for IPv4 and one for IPv6. The format of the IPV4-P2MP-LSP-IDENTIFIER TLV is shown in the following figure: 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=[TBD] | Length=16 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 Tunnel Sender Address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LSP ID | Tunnel ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Extended Tunnel ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | P2MP ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: IPV4-P2MP-LSP-IDENTIFIER TLV format Palle, et al. Expires August 18, 2014 [Page 7] Internet-Draft STATEFUL-P2MP February 2014 The type of the TLV is [TBD] and it has a fixed length of 12 octets. The value contains the following fields: IPv4 Tunnel Sender Address: contains the sender node's IPv4 address, as defined in [RFC3209], Section 4.6.2.1 for the LSP_TUNNEL_IPv4 Sender Template Object. LSP ID: contains the 16-bit 'LSP ID' identifier defined in [RFC3209], Section 4.6.2.1 for the LSP_TUNNEL_IPv4 Sender Template Object. Tunnel ID: contains the 16-bit 'Tunnel ID' identifier defined in [RFC3209], Section 4.6.1.1 for the LSP_TUNNEL_IPv4 Session Object. Tunnel ID remains constant over the life time of a tunnel. Extended Tunnel ID: contains the 32-bit 'Extended Tunnel ID' identifier defined in [RFC3209], Section 4.6.1.1 for the LSP_TUNNEL_IPv4 Session Object. P2MP ID: contains the 32-bit 'P2MP ID' identifier defined in Section 19.1.1 of [RFC4875]for the P2MP LSP Tunnel IPv4 SESSION Object. The format of the IPV6-P2MP-LSP-IDENTIFIER TLV is shown in the following figure: Palle, et al. Expires August 18, 2014 [Page 8] Internet-Draft STATEFUL-P2MP February 2014 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=[TBD] | Length=40 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | IPv6 tunnel sender address | + (16 octets) + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LSP ID | Tunnel ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | Extended Tunnel ID | + (16 octets) + | | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | P2MP ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: IPV6-P2MP-LSP-IDENTIFIER TLV format The type of the TLV is [TBD] and it has a fixed length of 24 octets. The value contains the following fields: IPv6 Tunnel Sender Address: contains the sender node's IPv6 address, as defined in [RFC3209], Section 4.6.2.2 for the LSP_TUNNEL_IPv6 Sender Template Object. LSP ID: contains the 16-bit 'LSP ID' identifier defined in [RFC3209], Section 4.6.2.2 for the LSP_TUNNEL_IPv6 Sender Template Object. Tunnel ID: contains the 16-bit 'Tunnel ID' identifier defined in [RFC3209], Section 4.6.1.2 for the LSP_TUNNEL_IPv6 Session Object. Tunnel ID remains constant over the life time of a tunnel. Extended Tunnel ID: contains the 128-bit 'Extended Tunnel ID' identifier defined in [RFC3209], Section 4.6.1.2 for the LSP_TUNNEL_IPv6 Session Object. Palle, et al. Expires August 18, 2014 [Page 9] Internet-Draft STATEFUL-P2MP February 2014 P2MP ID: As defined above in IPV4-P2MP-LSP-IDENTIFIERS TLV. 6.3. S2L Object The S2L (Source-to-Leaf) Object is used to report RSVP state of one or more destiantions(leaves) encoded within the END-POINTS object for a P2MP TE LSP. It MUST be carried in PCRpt message along with END- POINTS object when N bit is set in LSP object. The format of the S2L object is shown in the following figure: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags | O| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // Optional TLVs // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: S2L object format Flags(32 bits): O(Operational - 3 bits) the O Field represents the operational status of the group of destinations. The values are as per Operational field in LSP object defined in Section 7.3 of [I-D.ietf-pce-stateful-pce]. When N bit is set in LSP object then the O field in LSP object represents the operational status of the full P2MP TE LSP and the O field in S2L object represents the operational status of a group of destinations encoded within the END-POINTS object. Optional TLVs that may be included in the S2L Object. [Editor's Note: Further discussions are needed to find the need to encode Sub-Group Originator ID and Sub-Group ID in a TLVs.] 7. PCEP Message Extensions Palle, et al. Expires August 18, 2014 [Page 10] Internet-Draft STATEFUL-P2MP February 2014 7.1. The PCRpt Message As per Section 6.1 of [I-D.ietf-pce-stateful-pce], PCRpt message is used to report the current state of a P2P TE LSP. This document extends the PCRpt message in reporting the status of P2MP TE LSP. The format of PCRpt message is as follows: ::= Where: ::= [] ::= [] Where: ::= [] [] ::= (|) [] [] is defined in [RFC5440] and extended by PCEP extensions. The P2MP END-POINTS object defined in [RFC6006]is mandatory for specifying address of P2MP leaves grouped based on leaf types. o New leaves to add (leaf type = 1) o Old leaves to remove (leaf type = 2) o Old leaves whose path can be modified/reoptimized (leaf type = 3) o Old leaves whose path must be left unchanged (leaf type = 4) Palle, et al. Expires August 18, 2014 [Page 11] Internet-Draft STATEFUL-P2MP February 2014 When reporting the status of a P2MP TE LSP, the destinations are grouped in END-POINTS object based on the operational status (O field in S2L object) and leaf type (in END-POINTS). This way the leaves that share the same operational status are grouped together. For reporing the status of delegated P2MP TE LSP, leaf-type = 3, where as for non-delegated P2MP TE LSP, leaf-type = 4 is used. For delegated P2MP TE LSP configuration changes are reported via PCRpt message. For example, adding of new leaves END-POINTS (leaf- type = 1) is used where as removing of old leaves (leaf-type = 2) is used. Note that we preserve compatibility with the [I-D.ietf-pce-stateful-pce]definition of . At least one instance of MUST be present in this message. [Editor Note: suggest to add object mandatory in [I-D.ietf-pce-stateful-pce]document for ]. During state synchronization, the PCRpt message must report the status of the full P2MP TE LSP. 7.2. The PCUpd Message As per Section 6.2 of [I-D.ietf-pce-stateful-pce], PCUpd message is used to update P2P TE LSP attributes. This document extends the PCUpd message in updating the attributes of P2MP TE LSP. The format of a PCUpd message is as follows: Palle, et al. Expires August 18, 2014 [Page 12] Internet-Draft STATEFUL-P2MP February 2014 ::= Where: ::= [] ::= Where: ::= [] [] ::= (|) [] is defined in [RFC5440] and extended by PCEP extensions. Note that we preserve compatibility with the [I-D.ietf-pce-stateful-pce]definition of . 7.3. Example 7.3.1. P2MP TE LSP Update Request LSP Update Request message is sent by an active stateful PCE to update the P2MP TE LSP parameters or attributes. An example of a PCUpd message for P2MP TE LSP is described below: Common Header SRP LSP with P2MP flag set END-POINTS for leaf type 3 ERO list In this example, a stateful PCE request updation of path taken by some of the leaves in a P2MP tree. The update request uses the END- POINT type 3 (modified/reoptimized). The ERO list represents the S2L Palle, et al. Expires August 18, 2014 [Page 13] Internet-Draft STATEFUL-P2MP February 2014 path after modification. The update message does not need to encode the full P2MP tree in this case. 7.3.2. P2MP TE LSP Report LSP State Report message is sent by a PCC to report or delegate the P2MP TE LSP. An example of a PCRpt message for a delegated P2MP TE LSP is described below to add new leaves to an existing P2MP TE LSP: Common Header LSP with P2MP flag set END-POINTS for leaf type 1 S2L (O=DOWN) ERO list (empty) An example of a PCRpt message for P2MP TE LSP is described below to prune leaves from an existing P2MP TE LSP: Common Header LSP with P2MP flag set END-POINTS for leaf type 2 S2L (O=UP) ERO list An example of a PCRpt message for a delegated P2MP TE LSP is described below to report status of leaves in an existing P2MP TE LSP: Common Header LSP with P2MP flag set END-POINTS for leaf type 3 S2L (O=UP) ERO list END-POINTS for leaf type 3 S2L (O=DOWN) ERO list An example of a PCRpt message for a non-delegated P2MP TE LSP is described below to report status of leaves: Palle, et al. Expires August 18, 2014 [Page 14] Internet-Draft STATEFUL-P2MP February 2014 Common Header LSP with P2MP flag set END-POINTS for leaf type 4 S2L (O=ACTIVE) ERO list END-POINTS for leaf type 4 S2L (O=DOWN) ERO list 7.4. Report and Update Message Fragmentation The total PCEP message length, including the common header, is 16 bytes. In certain scenarios the P2MP report and update request may not fit into a single PCEP message (initial report or update). The F-bit is used in the LSP object to signal that the initial report or update was too large to fit into a single message and will be fragmented into multiple messages. In order to identify the single report or update, each message will use the same PLSP-ID. Fragmentation procedure described below for report or update message is similar to [RFC6006]which describes request and response message fragmentation. 7.4.1. Report Fragmentation Procedure If the initial report is too large to fit into a single report message, the PCC will split the report over multiple messages. Each message sent to the PCE, except the last one, will have the F-bit set in the LSP object to signify that the report has been fragmented into multiple messages. In order to identify that a series of report messages represents a single report, each message will use the same PLSP-ID. 7.4.2. Update Fragmentation Procedure Once the PCE computes and updates a path for some or all leaves in a P2MP TE LSP, an update message is sent to the PCC. If the update is too large to fit into a single update message, the PCE will split the update over multiple messages. Each update message sent by the PCE, except the last one, will have the F-bit set in the LSP object to signify that the update has been fragmented into multiple messages. In order to identify that a series of update messages represents a single update, each message will use the same PLSP-ID and SRP-ID- number. [Editor Note: P2MP message fragmentation errors associated with a P2MP path report and update will be defined in future version]. Palle, et al. Expires August 18, 2014 [Page 15] Internet-Draft STATEFUL-P2MP February 2014 8. Non-Support of P2MP TE LSPs for Stateful PCE The PCEP protocol extensions described in this document for stateful PCEs with P2MP capability MUST NOT be used if PCE has not advertised its stateful capability with P2MP as per Section 5.2. If this is not the case and Stateful operations on P2MP TE LSPs are attempted, then a PCErr with error-type 19 (Invalid Operation) and error-value TBD needs to be generated. If a Stateful PCE receives a P2MP TE LSP report message and it understands the P2MP flag in the LSP object, but the stateful PCE is not capable of P2MP computation, the PCE MUST send a PCErr message with error-type 19 (Invalid Operation) and error-value TBD. If a Stateful PCE receives a P2MP TE LSP report message and the PCE does not understand the P2MP flag in the LSP object, and therefore the PCEP extensions described in this document, then the PCE SHOULD reject the request. [Editor Note: more information on exact error value is needed] 9. Security Considerations TBD 10. Manageability Considerations 10.1. Control of Function and Policy TBD. 10.2. Information and Data Models TBD. 10.3. Liveness Detection and Monitoring TBD. 10.4. Verify Correct Operations TBD. 10.5. Requirements On Other Protocols TBD. Palle, et al. Expires August 18, 2014 [Page 16] Internet-Draft STATEFUL-P2MP February 2014 10.6. Impact On Network Operations TBD. 11. IANA Considerations This document requests IANA actions to allocate code points for the protocol elements defined in this document. Values shown here are suggested for use by IANA. 11.1. Extension of LSP Object This document requests that a registry is created to manage the Flags field of the LSP object. New values are to be assigned by Standards Action [RFC5226]. Each bit should be tracked with the following qualities: o Bit number (counting from bit 0 as the most significant bit) o Capability description o Defining RFC The following values are defined in this document: Bit Description Reference 24 P2MP This.I-D 23 Fragmentation This.I-D 11.2. Extension of PCEP-Error Object A new error types 6 and 19 defined in section 8.4 of [I-D.ietf-pce-stateful-pce]. This document extend the new Error- Values for those error types for the following error conditions: Error-Type Meaning 6 Mandatory Object missing Error-value=12: P2MP-LSP-IDENTIFIER TLV missing 19 Invalid Operation Error-value= TBD. Palle, et al. Expires August 18, 2014 [Page 17] Internet-Draft STATEFUL-P2MP February 2014 11.3. PCEP TLV Type Indicators This document defines the following new PCEP TLVs: Value Meaning Reference 22 P2MP-IPV4-LSP-IDENTIFIERS This.I-D 23 P2MP-IPV6-LSP-IDENTIFIERS This.I-D 12. Acknowledgments Thanks to Quintin Zhao for his comments. 13. References 13.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5440, March 2009. [I-D.ietf-pce-stateful-pce] Crabbe, E., Medved, J., Minei, I., and R. Varga, "PCEP Extensions for Stateful PCE", draft-ietf-pce-stateful- pce-07 (work in progress), October 2013. 13.2. Informative References [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. [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, August 2006. [RFC4857] Fogelstroem, E., Jonsson, A., and C. Perkins, "Mobile IPv4 Regional Registration", RFC 4857, June 2007. [RFC4875] Aggarwal, R., Papadimitriou, D., and S. Yasukawa, "Extensions to Resource Reservation Protocol - Traffic Engineering (RSVP-TE) for Point-to-Multipoint TE Label Switched Paths (LSPs)", RFC 4875, May 2007. Palle, et al. Expires August 18, 2014 [Page 18] Internet-Draft STATEFUL-P2MP February 2014 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. [RFC5671] Yasukawa, S. and A. Farrel, "Applicability of the Path Computation Element (PCE) to Point-to-Multipoint (P2MP) MPLS and GMPLS Traffic Engineering (TE)", RFC 5671, October 2009. [RFC6006] Zhao, Q., King, D., Verhaeghe, F., Takeda, T., Ali, Z., and J. Meuric, "Extensions to the Path Computation Element Communication Protocol (PCEP) for Point-to-Multipoint Traffic Engineering Label Switched Paths", RFC 6006, September 2010. [I-D.ietf-pce-stateful-pce-app] Zhang, X. and I. Minei, "Applicability of Stateful Path Computation Element (PCE)", draft-ietf-pce-stateful-pce- app-01 (work in progress), September 2013. [I-D.sivabalan-pce-disco-stateful] Sivabalan, S., Medved, J., and X. Zhang, "IGP Extensions for Stateful PCE Discovery", draft-sivabalan-pce-disco- stateful-03 (work in progress), January 2014. Authors' Addresses Udayasree Palle Huawei Technologies Leela Palace Bangalore, Karnataka 560008 INDIA EMail: udayasree.palle@huawei.com Dhruv Dhody Huawei Technologies Leela Palace Bangalore, Karnataka 560008 INDIA EMail: dhruv.ietf@gmail.com Palle, et al. Expires August 18, 2014 [Page 19] Internet-Draft STATEFUL-P2MP February 2014 Yosuke Tanaka NTT Communications Corporation Granpark Tower 3-4-1 Shibaura, Minato-ku Tokyo 108-8118 Japan EMail: yosuke.tanaka@ntt.com Yuji Kamite NTT Communications Corporation Granpark Tower 3-4-1 Shibaura, Minato-ku Tokyo 108-8118 Japan EMail: y.kamite@ntt.com Palle, et al. Expires August 18, 2014 [Page 20]