Network Working Group X. Fu Internet-Draft Y. Bao Intended status: Standards Track ZTE Corporation Expires: September 2, 2010 March 1, 2010 Framework for MPLS-TP Ownership Transfer Between Management Plane and Control Plane draft-fuxh-mpls-tp-transfer-framework-00 Abstract In MPLS-TP architecture, LSP and PW provisioning can be done either by Control Plane (CP) or Management Plane (MP). The MPLS-TP control plane must provide a mechanism for dynamic ownership transfer of the control of MPLS-TP transport paths from MP to CP and vice versa. [draft-bao-mpls-tp-path-transfer-reqs-00] defines requirement for MPLS-TP paths ownership transfer from MP to CP and vice versa. This document provides a framework to allow the development of protocol extensions to support the MPLS-TP paths ownership transfer between MP and CP and vice versa. Conventions Used In This Document 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 RFC 2119 [RFC2119]. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at Fu & Bao Expires September 2, 2010 [Page 1] Internet-Draft Framework for MPLS-TP Ownership Transfer March 2010 http://www.ietf.org/shadow.html. This Internet-Draft will expire on September 2, 2010. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. 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 BSD License. Fu & Bao Expires September 2, 2010 [Page 2] Internet-Draft Framework for MPLS-TP Ownership Transfer March 2010 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Ownership Transfer Procedures . . . . . . . . . . . . . . . . . 3 2.1. Ownership Transfer Procedure for Associated LSP . . . . . . 3 2.1.1. Associated LSP Ownership Transfer From MP to CP . . . . 3 2.1.2. Associated LSP Ownership Transfer From CP to MP . . . . 4 2.2. Ownership Transfer Procedures for PW . . . . . . . . . . . 4 2.2.1. PW Ownership Transfer From MP to CP . . . . . . . . . . 4 2.2.2. PW Ownership Transfer From CP to MP . . . . . . . . . . 7 3. Security Considerations . . . . . . . . . . . . . . . . . . . . 8 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 5.1. Normative References . . . . . . . . . . . . . . . . . . . 8 5.2. Informative References . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9 Fu & Bao Expires September 2, 2010 [Page 3] Internet-Draft Framework for MPLS-TP Ownership Transfer March 2010 1. Introduction In terms of MPLS-TP requirement, an MPLS-TP control plane MUST provide a mechanism for dynamic ownership transfer of the control of MPLS-TP transport paths from the Management Plane (MP) to the Control Plane (CP) and vice versa. In MPLS-TP architecture, LSP and PW provisioning can be done either by Control Plane or Management Plane. The MPLS-TP control plane must support unidirectional, associated bidirectional and co-routed bidirectional point-to-point transport paths. [RFC5493] defines the specific requirements for an LSP ownership transfer procedure. [PC-SPC] describes an extension to GMPLS RSVP-TE signaling that enables the LSP ownership transfer between the Management Plane and the Control Plane. Ownership transfers of the forward and the backward directions belonging to the same associated bidirectional transport path can't be done in the same signaling procedure. Edge nodes (i.e., ingress, egress and intermediate) must be aware about the pairing relationship of the forward and the backward directions belonging to the same associated bidirectional transport path. Ownership transfer procedures of the forward and the backward directions must be associated. This document describes the ownership transfer related procedures for associated LSP. [draft-bao-mpls-tp-path-transfer-reqs-00] defines the requirements for ownership transfer of existing PWs provisioned by NMS from the MP to the CP without disrupting user traffic flowing on them. This document describes the ownership transfer related procedures for PWs. 2. Ownership Transfer Procedures The ownership transfer of unidirectional and co-routed bidirectional LSPs is based on the [RFC5493] and [PC-SPC] 2.1. Ownership Transfer Procedure for Associated LSP 2.1.1. Associated LSP Ownership Transfer From MP to CP Forward and backward paths belonging to the same associated LSP are signalled/routed independently in MPLS-TP networks. So ownership transfers from MP to CP of the forward and the backward directions belonging to the same associated bidirectional transport path can't be done in the same signaling procedure. But ownership transfer of each direction should be based on [RFC5493] and [PC-SPC]. In order to make edge nodes (i.e., ingress, egress and intermediate) Fu & Bao Expires September 2, 2010 [Page 4] Internet-Draft Framework for MPLS-TP Ownership Transfer March 2010 be aware about the pairing relationship of the forward and the backward directions belonging to the same associated bidirectional transport path, ownership transfer procedures of the forward and the backward directions must be associated. The ASSOCIATION object, as defined in RFC 4872 and RFC 4873 respectively, is used to provide end-to-end and segment recovery. Furthermore, draft-berger-ccamp-assoc-info-00.txt described how to utilize it in detail. [draft-zhang-mpls-tp-rsvpte-ext-associated-lsp-00] defines a mechanism to associated the forward and the backward direction LSPs to be an associated LSP. It extends the ASSOCIATION Object and defines a new Association Type. An ASSOCIATION object with an Association Type set to the value "Association" is used to bind two reverse unidirectional LSP to be an associated bidirectional LSP. Any node originating the forward or backward direction LSP MUST insert an ASSOCIATION object with an Association Type set to the value "Association". The Association ID MUST be set to a value that uniquely identifies the reverse direction LSP. Egress or intermediate nodes MUST use ASSOCIATION object(s) with the Association Type set to the value "Association" to bind the two reverse unidirectional LSPs together. 2.1.2. Associated LSP Ownership Transfer From CP to MP Ownership transfers from CP to MP of the forward and the backward directions belonging to the same associated bidirectional transport path also can't be done in the same signaling procedure. But ownership transfer from CP to MP of each direction should be based on [RFC5493] and [PC-SPC]. 2.2. Ownership Transfer Procedures for PW 2.2.1. PW Ownership Transfer From MP to CP 2.2.1.1. SS-PW Ownership Transfer From MP to CP SS-PW in MPLS-TP network signaling control plane is based on LDP with specific procedures defined in [RFC4447]. [Segmented-PW] and [MS-PW] allow for static switching of multi-segment pseudowires whereby signaling is still based on Targeted LDP (T-LDP). The ownership transfer procedure from MP to CP for PW (SS-PW and MS-PW) MUST create LDP sessions along the path which is transfered. The ownership transfer procedure for SS-PW must create an LDP session between PE1 and PE2. The ownership transfer procecure for SS-PW MUST Fu & Bao Expires September 2, 2010 [Page 5] Internet-Draft Framework for MPLS-TP Ownership Transfer March 2010 NOT cause any disruption of user traffic flowing over the PW whose control is being transferred. If the ownership transfer fails, the data plane MUST not be affected. The operator can synchronously instruct PE1 and PE2 to transfer control of the PW from the MP to the CP. PE1 initiates the ownership transfer by sending a Label Mapping Message to the ingress PE (PE2). PE2 also initiates the ownership transfer by sending a Label Mapping Message to the ingress PE (PE1). The Label Mapping message contains an FEC TLV, a Label TLV, and optional parameter TLVs. The signaling procedure must be based on [RFC4447]. The Status TLV defined in [RFC3337] is transported to the remote PW peer via the LDP Notification message. [draft-bao-pw3-pw-transfer-ldp-ext-00] defines an LDP extension by adding a PW Ownership Handover TLV to provide a mechanism to identify the LDP message of ownership transfer. The Egress node originating the LDP Mapping message of ownership transfer must insert a PW Ownership Handover TLV with a flag set to the value "Handover". The ingress that receives a LDP message must use the flag set to the value "Handover" to identify ownership transfer. It should not do the FEC and Label Mapping anymore. |<-------------- Emulated Service ---------------->| | | | |<------- Pseudowire ------->| | | | | | |Attachment| |<-- PSN Tunnel -->| |Attachment| | Circuit V V V V Circuit | V (AC) +----+ +----+ (AC) V +-----+ | | PE1|==================| PE2| | +-----+ | |----------|............PW1.............|----------| | | CE1 | | | | | | | | CE2 | | |----------|............PW2.............|----------| | +-----+ ^ | | |==================| | | ^ +-----+ ^ | +----+ +----+ | | ^ | | Provider Edge 1 Provider Edge 2 | | | | | | Customer | | Customer Edge 1 | | Edge 2 | | native service native service Figure 1: SS-PWE Reference Model Fu & Bao Expires September 2, 2010 [Page 6] Internet-Draft Framework for MPLS-TP Ownership Transfer March 2010 2.2.1.2. MS-PW Ownership Transfer From MP to CP The ownership transfer procedure for MS-PW must also create LDP sessions between T-PE1 and S-PE1, S-PE1 and S-PE2, and the other one between S-PE2 and T-PE2. The operator instructs T-PE1 to transfer control of the PW from the MP to the CP. In order to creat LDP sessions along the path of MS-PW, operator must give full information about the explicit route of MS-PW including the S-PEs (S-PE1 and S-PE2) traversed by PW. The ownership transfer procedure of each PW segment is based on the section 2.2.1.1, but the Label Mapping message must carry the explicit route of MS-PW including S-PE1 and S-PE2 encoded in S-PE TLV. After S-PE1 receive the Label Mapping message, it needs to get the next S-PEs (S-PE2) from the S-PE TLV and create the LDP session between S-PE1 and S-PE2. The node originating the LDP Mapping message of ownership transfer must insert a PW Ownership Handover TLV with a flag set to the value "Handover" defined in [draft-bao-pw3-pw-transfer-ldp-ext-00]. The ingress that receives a LDP Mapping message must use the flag set to the value "Handover" to identify ownership transfer. It should not do the FEC and Label Mapping anymore. Native |<---------------------- MS-PW ---------------------->| Native Service | |<-PSN1-->| |<--PSN2->| |<--PSN3->| | Service (AC) V V V V V V V V (AC) | +-----+ +-----+ +-----+ +-----+ +----+ | |T-PE1| |S-PE1| |S-PE2| |T-PE2| | +----+ | | | | |=========| |=========| |=========| | | | | | |------|......PW.Seg't1.......PW Seg't3.......PW Seg't5......|-----| | | CE1| | | | | | | | | | | |CE2 | | |------|......PW.Seg't2......|PW Seg't4......|PW Seg't6......|-----| | | | | | |=========| |=========| |=========| | | | | +----+ +-----+ +-----+ +-----+ +-----+ +----+ ^ ^ | | | | |<----------------------- Emulated Service ----------------------->| Figure 2: MS-PW switching Reference Model Fu & Bao Expires September 2, 2010 [Page 7] Internet-Draft Framework for MPLS-TP Ownership Transfer March 2010 2.2.2. PW Ownership Transfer From CP to MP The CP has the ownership and control of the PW. The CP to MP transfer procedure MUST delete the existing LDP session information and MUST NOT affect the cross-connected resources, but just move their ownership to the MP. 2.2.2.1. SS-PW Ownership Transfer From MP to CP The ownership transfer procedure for SS-PW must delete the existing LDP session between PE1 and PE2. . The operator can synchronously instruct PE1 and PE2 to transfer control of the PW from the CP to the MP. PE1 initiates the ownership transfer by sending a Label Withdraw message to the ingress PE (PE2). PE2 also initiates the ownership transfer by sending a Label Withdraw message to the ingress PE (PE1). The signaling procedure must be based on [RFC4447]. [draft-bao-pw3-pw-transfer-ldp-ext-00] defines an LDP extension by adding a PW Ownership Handover TLV to provide a mechanism to identify the LDP message of ownership transfer. The Egress node originating the Label Withdraw message of ownership transfer must insert a PW Ownership Handover TLV with a flag set to the value "Handover". The ingress that receives a Label Withdraw message must use the flag set to the value "Handover" to identify ownership transfer. There is no any action is taken over the Data Plane anymore. 2.2.2.2. MS-PW Ownership Transfer From MP to CP The ownership transfer procedure for MS-PW must also delete LDP sessions between T-PE1 and S-PE1, S-PE1 and S-PE2, and the other one between S-PE2 and T-PE2. The operator instructs T-PE1 to transfer control of the PW from the CP to the MP. In order to delete LDP sessions along the path of MS-PW, the CP must give full information about the explicit route of MS-PW including the S-PEs (S-PE1 and S-PE2) traversed by PW. The ownership transfer procedure of each PW segment is based on the section 2.2.2.1, but the Label Withdraw message must carry the explicit route of MS-PW including S-PE1 and S-PE2 encoded in S-PE TLV. After S-PE1 receive the Label Withdraw message, it needs to get the next S-PEs (S-PE2) from the S-PE TLV and delete the LDP session between S-PE1 and S-PE2. The node originating the LDP Withdraw message of ownership transfer must insert a PW Ownership Handover TLV with a flag set to the value Fu & Bao Expires September 2, 2010 [Page 8] Internet-Draft Framework for MPLS-TP Ownership Transfer March 2010 "Handover" defined in [draft-bao-pw3-pw-transfer-ldp-ext-00]. The ingress that receives a LDP Withdraw message must use the flag set to the value "Handover" to identify ownership transfer. There is no any action is taken over the Data Plane anymore. 3. Security Considerations TBD 4. IANA Considerations TBD 5. References 5.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3036] Andersson, L., Doolan, P., Feldman, N., Fredette, A., and B. Thomas, "LDP Specification", RFC 3036, January 2001. [RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP Specification", RFC 5036, October 2007. [RFC4447] Martini, L., Rosen, E., El-Aawar, N., Smith, T., and G. Heron, "Pseudowire Setup and Maintenance Using the Label Distribution Protocol (LDP)", RFC 4447, April 2006. [RFC5493] Caviglia, D., Bramanti, D., Li, D., and D. McDysan, "Requirements for the Conversion between Permanent Connections and Switched Connections in a Generalized Multiprotocol Label Switching (GMPLS) Network", RFC 5493, April 2009. [RFC5654] Niven-Jenkins, B., Brungard, D., Betts, M., Sprecher, N., and S. Ueno, "Requirements of an MPLS Transport Profile", RFC 5654, September 2009. 5.2. Informative References [I-D.ietf-ccamp-pc-spc-rsvpte-ext] Caviglia, D., Ceccarelli, D., Li, D., and S. Bardalai, "RSVP-TE Signaling Extension For Management Plane To Fu & Bao Expires September 2, 2010 [Page 9] Internet-Draft Framework for MPLS-TP Ownership Transfer March 2010 Control Plane LSP Handover In A GMPLS Enabled Transport Network.", draft-ietf-ccamp-pc-spc-rsvpte-ext-07 (work in progress), February 2010. [I-D.ietf-pwe3-ms-pw-arch] Bocci, M. and S. Bryant, "An Architecture for Multi- Segment Pseudowire Emulation Edge-to-Edge", draft-ietf-pwe3-ms-pw-arch-07 (work in progress), July 2009. [I-D.abfb-mpls-tp-control-plane-framework] Andersson, L., Berger, L., Fang, L., Bitar, N., Takacs, A., Vigoureux, M., and E. Bellagamba, "MPLS-TP Control Plane Framework", draft-abfb-mpls-tp-control-plane-framework-02 (work in progress), February 2010. [I-D.ietf-mpls-tp-framework] Bocci, M., Bryant, S., Frost, D., Levrau, L., and L. Berger, "A Framework for MPLS in Transport Networks", draft-ietf-mpls-tp-framework-10 (work in progress), February 2010. Authors' Addresses Xihua Fu ZTE Corporation West District,ZTE Plaza,No.10,Tangyan South Road,Gaoxin District Xi An 710065 P.R.China Phone: +8613798412242 Email: fu.xihua@zte.com.cn URI: http://wwwen.zte.com.cn/ Yuanlin Bao ZTE Corporation 5F,R&D Building 3, ZTE Industrial Park, XiLi LiuXian Road Nanshan District,Shenzhen 518055 P.R.China Phone: +86 755 26773731 Email: bao.yuanlin@zte.com.cn URI: http://wwwen.zte.com.cn/ Fu & Bao Expires September 2, 2010 [Page 10]