PWE3 Working Group G. Liu Internet-Draft ZTE Corporation Intended status: Informational June 09, 2013 Expires: December 11, 2013 p2mp pw protection for MPLS-TP network draft-liu-pwe3-mpls-tp-p2mp-pw-protection-03 Abstract The requirements of MPLS-TP in RFC 5654 include a requirement(R63) that requires MPLS-TP MUST be possible to provide protection for MPLS-TP data plane without any IP forwarding capability and control plane.If applying 1:1 protection mechanism for the p2mp traffic in rfc6718 , it must have a return path to coordinate switch state to select the same path to receive and send traffic packet.For the above problem,this document describes a kind of protection solution to recovery and protect the p2mp traffic under the failure condition. This document is a product of a joint Internet Task Force(IETF) / International Telecommunications Union Telecommunications Standardization Sector (ITU-T) effort to include an MPLS Transport Profile within the IETF MPLS and PWE3 architectures to support the capabilities and functionalities of a packet transport network as defined by the ITU-T. 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 December 11, 2013. Liu Expires December 11, 2013 [Page 1] Internet-Draft p2mp pw protection for mpls-tp network June 2013 Copyright Notice Copyright (c) 2013 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 Simplified BSD License. This document may not be modified, and derivative works of it may not be created, and it may not be published except as an Internet-Draft. Table of Contents 1. Problem statement . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions used in this document . . . . . . . . . . . . . . 3 3. Protection Mechanism . . . . . . . . . . . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . 6 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 6 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 7.1. Normative References . . . . . . . . . . . . . . . . . . 6 7.2. URL References . . . . . . . . . . . . . . . . . . . . . 6 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6 1. Problem statement According to MPLS-TP requirement(RFC 5654), It requires that MPLS-TP data plane is independent of control plane and IP forwarding capability. So it means that MPLS-TP data plane can still work without control plane and any IP forwarding capability.It must be essential for unidiretional path including p2p or p2mp path to set up a return path between any two end nodes . So it costs more configuration and maintenece . While this document provides a protection mechanism for p2mp traffic without return path, IP forwarding capability and control plane. Liu Expires December 11, 2013 [Page 2] Internet-Draft p2mp pw protection for mpls-tp network June 2013 2. 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. OAM: Operation, Administration, Maintenance LSP: Label Switched Path. PW: Pseudowire P2MP:Point to Multi-Point P2P:Point to Point PSC:Protection Switching Coordination CE:Customer Equipment LER:Label Edge Router LSR:Label Switch Router IP: Interenet Protocol MPLS-TP:Multi-Protocol Label Switching Transport Profile ME: Maintenance Entity MEP:MEG End Point CE: Customer Equipment 3. Protection Mechanism This section will describe a protection mechanism for p2mp pw path,which regards a leaf node as protector node of another leaf node on the p2mp pw path.The two leaf nodes protect each other.in addtion, In order to be easy to access to CE node, It should select LER as backup node which will connect protector node and CE node. If the backup node is still a leaf node of the p2mp pw path ,in a result, the protector node and the backup node are the same node. in addtion, A bidirectional p2p pw should be configurated between the protected node and the backup node or the protector node , and between the protector node and the backup node .Just as the following figure 1: Liu Expires December 11, 2013 [Page 3] Internet-Draft p2mp pw protection for mpls-tp network June 2013 ___ ___ ___ */LSR\ ********* /LER\########## /CE1\ * \ A / \_1_/ # \___/ __ * - - + # /LER\* . _+_ # /LER\# \_O_/* . \_2_/# * . + # * ___ _+_ # ___ * /LSR\ /LER\ # /CE2\ * \ B / ********** \_3_/########### \___/ - - ***** working pw +++++ protection pw ##### access link Figure 1: p2mp pw protection configuration topology figure LER0 is root node of a p2mp pw, LER1 and LER3 are leaf nodes of the p2mp pw. LER2 is a backup node for LER1 and LER3. When the protected node LER1 or LER3 has a failure, its backup node LER2 will replace of the protected node LER1 or LER3 to transmit the protected p2mp traffic to CE1 or CE2. If LER1 has a failure, LER2 MUST detect the failure by PW OAM. Then LER2 will notify its protector node LER3 of the failure by pw status message[1]. When LER3 receives the failure status message, it will begin to duplicate the p2mp traffic to send to LER2 by pre-configured p2p protection pw. Then LER2 sends the p2mp traffic to CE1 by its access link(LER2-CE1) ,Just as the following figure 2. ___ _X_ ___ */LSR\ ********* /LER\########## /CE1\ * \ A / \_1_/ # \___/ __ * - - + # /LER\* . _+_ # /LER\# \_O_/* . \_2_/# * . + # * ___ _+_ # ___ * /LSR\ /LER\ # /CE2\ * \ B / ********** \_3_/########### \___/ - - Liu Expires December 11, 2013 [Page 4] Internet-Draft p2mp pw protection for mpls-tp network June 2013 ***** working pw +++++ protection pw ##### access link X failure Figure 2: node failure When a leaf node detects a failure on its working pw , it will notify the failure of its backup node or protector node by pw status message[1]. So its backup node or protector node will transmit the protected p2mp traffic to the protected node.Just as the following figure 3. ___ ___ ___ */LSR\ *****X**** /LER\######### /CE1\ * \ A / \_1_/ # \___/ __ * - - + # /LER\* . _+_ # /LER\# \_O_/* . \_2_/# * . + # * ___ _+_ # ___ * /LSR\ /LER\ # /CE2\ * \ B / ********** \_3_/########### \___/ - - ***** working pw +++++ protection pw ##### access link X failure Figure 3: working pw failure Liu Expires December 11, 2013 [Page 5] Internet-Draft p2mp pw protection for mpls-tp network June 2013 When a failure happens on the branch working pw path(LER0-LSRA-LER1), the protected node LER1 will detect the failure and inform the failure of its backup node LER2 and protector node LER3. Then LER2 and LER3 receive the failure message from LER1 ,LER3 will duplicate the protected p2mp traffic to send to the backup node LER2 firstly by its protection pw between LER2 and LER3. Then LER2 sends the traffic to the protected node LER1 by the protection pw between LER1 and LER2. At last CE1 will receive the traffic by its access link(LER1-CE1) 4. Security Considerations TBD 5. IANA Considerations TBD. 6. Acknowledgments TBD . 7. References 7.1. Normative References [RFC5654] IETF, "IETF RFC5654(MPLS-TP requirement) ", September 2009. [RFC5921] IETF, "IETF RFC5654(MPLS-TP framework) ", July 2010. [RFC6478] IETF, "IETF RFC6478(Pseudowire Status for Static Pseudowires) ", May 2012. [RFC6718] IETF, "IETF RFC6718(Pseudowire Redundancy) ", August 2012. [RFC6870] IETF, "IETF RFC6870(Pseudowire Preferential Forwarding Status Bit) ", February 2013. 7.2. URL References [MPLS-TP-22] IETF - ITU-T Joint Working Team, 2008, . Author's Address Liu Expires December 11, 2013 [Page 6] Internet-Draft p2mp pw protection for mpls-tp network June 2013 Guoman Liu ZTE Corporation No.50, Ruanjian Road, Yuhuatai District Nanjing 210012 P.R.China Phone: +86 025 88014227 Email: liu.guoman@zte.com.cn Liu Expires December 11, 2013 [Page 7]