Network Working Group Yuanlin Bao Internet-Draft Xihua Fu Intended status: Informational Fei Zhang Expires: September 1, 2010 ZTE Corporation February 28, 2010 LDP Signaling Extension For Management Plane To Control Plane PW Ownership Transfer In A MPLS-TP Network draft-bao-pwe3-pw-transfer-ldp-ext-00.txt Abstract This memo describes an extension to LDP signaling that enables the PW ownership transfer between the Management Plane and the Control Plane. This document defines all PW transfer related procedures. This includes the handling of failure conditions and subsequent reversion to original state. A basic premise of the extension is that the transfer procedures must never impact an already established Data plane connection. 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 http://www.ietf.org/shadow.html. This Internet-Draft will expire on September 1, 2010. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. Yuanlin Bao, et al. Expires September 1, 2010 [Page 1] Internet-Draft LDP ext for PW Transfer February 2010 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Conventions used in this document . . . . . . . . . . . . . 3 2. LDP Extension . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. PW Ownership Transfer TLV . . . . . . . . . . . . . . . . . 4 3. PW Transfer Procedure . . . . . . . . . . . . . . . . . . . . . 4 3.1. PW Ownership Transfer from MP to CP . . . . . . . . . . . . 4 3.1.1. MS-PW specification . . . . . . . . . . . . . . . . . . 5 3.1.2. Failure Handling . . . . . . . . . . . . . . . . . . . 5 3.2. PW Ownership Transfer from CP to MP . . . . . . . . . . . . 5 3.2.1. Failure Handling . . . . . . . . . . . . . . . . . . . 5 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6 7.1. Normative References . . . . . . . . . . . . . . . . . . . 6 7.2. Informative References . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Yuanlin Bao, et al. Expires September 1, 2010 [Page 2] Internet-Draft LDP ext for PW Transfer February 2010 1. Introduction As defined in [RFC3985] PWE3 is a mechanism that emulates the essential attributes of a telecommunications service (such as a T1 leased line or Frame Relay) over a PSN. Traditionally, pseudowir (PW) are controlled by means of a Network Management System (NMS) operating within the Management Plane (MP). NMS/MP is the owner of PW, being responsible of it's set up, tear down and maintenance. The adoption of a PW Control Plane ([RFC4447] and [DYNAMIC-MS-PW]) in a network that is already in service - controlled by NMS at MP level - introduces the need for a procedure able to coordinate a control transfer of PW from MP to CP. In addition, the control transfer in the opposite direction, from CP to MP should be possible as well. The procedures described in this memo can be applied to a PW in any DP switching technology and any network architecture. This memo describes an extension to LDP Protocol [RFC4447], [RFC5036] signaling that enables the transfer of PW ownership between the Management and the Control Planes. All transfer related procedures are defined below. This includes the handling of failure conditions and subsequent reversion to original state. A basic premise of the extension is that the transfer procedures must never impact the exchange of user data on PWs that are already established in the data plane. 1.1. 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 [RFC2119]. 2. LDP Extension To ensure the PW ownership transfer between MP and CP automatically, T-PE/S-PE SHOULD has the knowledge that it is the PW transfer signaling message. Furthermore, for MS-PW transfer T-PE/S-PE SHOULD know the next hop, so, the PW path MUST be carried in the LDP Label Mapping message. Since [SEG-PW] has defined PW switching point TLV (S-PE TLV) and Sub-TLV to the switching points that the PW traverses, so S-PE TLV and Sub-TLV can be used to carry the PW path. Therefore, this section only defines a new LDP TLV - Transfer TLV - which can be used to indicate a PW transfer signaling procedure. Yuanlin Bao, et al. Expires September 1, 2010 [Page 3] Internet-Draft LDP ext for PW Transfer February 2010 2.1. PW Ownership Transfer TLV The PW Ownership Transfer TLV (PW-OH TLV) is defined as following: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0| PW Transfer (0x0xxxx) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |POT| +-+-+ Figure 1: PW Ownership Transfer TLV POT (2 bits): PW Ownership Transfer. This TLV is optional and carried in Optional Parameters of LDP Label Mapping and Label Withdraw message defined in [RFC5036]. 01 - PW ownership transfer from management plane to control plane 11 - PW ownership transfer from control plane to management plane 3. PW Transfer Procedure 3.1. PW Ownership Transfer from MP to CP The MP to CP PW transfer procedure MUST create a LDP session along the path of the PW to be transfer from MP to CP, associat the LDP session to the existing FEC-Label mapping owned by the MP and at the same time transfer PW ownership to the CP. The operator instructs the source/destinational T-PE to transfer control of the PW from the MP to the CP. For MS-PW operator MUST also supply the exact path of the MS-PW and FEC-Label mapping information. The source/destinational T-PE MUST check that no corresponding LDP state exists and that corresponding Data Plane state does exist. If there is an error, this MUST be reported to the operator and further protocol action MUST NOT be taken. The source/destination T-PE completes the LDP initialization as the procedure described in [RFC5036] and [RFC4447]. After the LDP initialization, the source T-PE SHOULD sends a Label Mapping message with PW Ownership Transfer TLV in Optional Parameters to it's LDP peer the destination T-PE, and vis versa. When destination/source T-PE receives this PW transfer Label Mapping message, it only creates Yuanlin Bao, et al. Expires September 1, 2010 [Page 4] Internet-Draft LDP ext for PW Transfer February 2010 the LDP signaling state on the control plane, and any action for data plane MUST not be triggered. 3.1.1. MS-PW specification o The behaviour of T-PE The source/destination T-PE of PW transfering from MP to CP, SHOULD encond the PW path into S-PE TLV and Sub-TLV and set the Ho of PW-OH TLV to 01, then encond these TLVs into Label Mapping message. After source/destination T-PE completes the Label Message enconding, it sends the message to the downstream node, i.e. S-PE. o The behaviour of S-PE When S-PE receives the PW transfer Label Mapping message, it SHOULD create the PW signaling state in the control plane, and get the next hop from the S-PE TLV and Sub-TLV. After S-PE creates the PW signaling state in the control plane, it sends the PW transfer LDP Label Mapping message to the next hop. 3.1.2. Failure Handling This section is to be studied in the next version. 3.2. PW Ownership Transfer from CP to MP 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. That is, after PW ownership transfer from CP to MP, the PW is no longer under control of LDP. The source/destination T-PE node MUST send a Label Withdraw message in the downstream direction with the Ho of PW-OH TLV set to 11 carried in Optional Parameters. No action is taken over the DP. For MS-PW, S-PE must forward such message towards the source or destination node for forward and reverse direction respectively. Downstream nodes processing a Label Withdraw message MUST NOT remove any associated data plane state. 3.2.1. Failure Handling This section is to be studied in the next version. Yuanlin Bao, et al. Expires September 1, 2010 [Page 5] Internet-Draft LDP ext for PW Transfer February 2010 4. Security Considerations TBD. 5. IANA Considerations TBD. 6. Acknowledgements The RFC text was produced using Marshall Rose's xml2rfc tool. 7. References 7.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3985] Bryant, S. and P. Pate, "Pseudo Wire Emulation Edge-to- Edge (PWE3) Architecture", RFC 3985, March 2005. [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. [RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP Specification", RFC 5036, October 2007. [RFC5659] Bocci, M. and S. Bryant, "An Architecture for Multi- Segment Pseudowire Emulation Edge-to-Edge", RFC 5659, October 2009. 7.2. Informative References [DYNAMIC-MS-PW] Luca Martini, Matthew Bocci, and Florin Balus, "Dynamic Placement of Multi Segment Pseudo Wires", draft-ietf-pwe3-dynamic-ms-pw-10.txt Working in progress. [MPLS-TP-CP] Loa Andersson, Lou Berger, and Luyuan Fang, "MPLS-TP Control Plane Framework", draft-abfb-mpls-tp-control-plane-framework-01.txt Working in progress. Yuanlin Bao, et al. Expires September 1, 2010 [Page 6] Internet-Draft LDP ext for PW Transfer February 2010 [SEG-PW] Luca Martini and Chris Metz, "Segmented Pseudowire", draft-ietf-pwe3-segmented-pw-13.txt Working in progress. Authors' Addresses 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://www.zte.com.cn/ Xihua Fu ZTE Corporation West District,ZTE Plaza,No.10,Tangyan South Road,Gaoxin District Xi An 710065 P.R.China Phone: +86 13798412242 Email: fu.xihua@zte.com.cn URI: http://www.zte.com.cn/ Fei Zhang ZTE Corporation NO.68, Zijinhua Road, Yuhuatai District Nanjing 210000 P.R.China Phone: +86 25 52877612 Email: zhang.fei3@zte.com.cn Yuanlin Bao, et al. Expires September 1, 2010 [Page 7]