MPLS Working Group G. Liu Internet-Draft ZTE Corporation Intended status: Informational Y. Weingarten Expires: October 28, 2012 April 26, 2012 MPLS-TP protection for interconnected rings draft-liu-mpls-tp-interconnected-ring-protection-01 Abstract According to the ring protection Requirements in RFC 5654, Requirement 93 : When a network is constructed from interconnected rings, MPLS-TP MUST support recovery mechanisms that protect user data that traverses more than one ring. This includes the possibility of failure of the ring-interconnect nodes and links,so this document will describle all kinds of interconnected ring Scenarios and several protection solutions for recovery the failure of the ring-interconnect nodes and Links. . 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. This document may not be modified, and derivative works of it may not be created, and it may not be published except as an Internet-Draft. 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 October 28, 2012. Copyright Notice Liu & Weingarten Expires October 28, 2012 [Page 1] Internet-Draft MPLS-TP protection April 2012 Copyright (c) 2012 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions used in this document . . . . . . . . . . . . . . 7 3. recovery mechanisms . . . . . . . . . . . . . . . . . . . . . 8 3.1. recovery mechanism for Dual-node interconnected-ring . . . 8 3.2. recovery mechanism for Chained interconnected-ring . . . . 8 3.3. recovery mechanism for Dual-node and Single-node mixed interconnected-ring . . . . . . . . . . . . . . . . . . . 9 3.4. recovery mechanism for Dual-node and Chained mixed interconnected-ring . . . . . . . . . . . . . . . . . . . 9 3.5. recovery mechanism for Single-node and Chained mixed interconnected-ring . . . . . . . . . . . . . . . . . . . 9 3.6. recovery mechanism for Dual-node ,Single-node and Chained mixed interconnected-ring . . . . . . . . . . . . 9 4. Security Considerations . . . . . . . . . . . . . . . . . . . 9 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 9 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7.1. Normative References . . . . . . . . . . . . . . . . . . . 10 7.2. Informative References . . . . . . . . . . . . . . . . . . 10 7.3. URL References . . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10 Liu & Weingarten Expires October 28, 2012 [Page 2] Internet-Draft MPLS-TP protection April 2012 1. Introduction This document describles different interconnected ring scenarios and several protection solutions to protect against the failure of the ring-interconnect nodes and links. there are mainly three common interconnection scenarios that we will address in this document: Dual-node interconnection - when the interconnected rings are interconnected by two nodes from each ring (see Figure 1); Single-node interconnection - when the connection between the interconnected rings are through a single node (see Figure 2).As the interconnnection node(LSR-A) is a single-point of failure, such the interconnection scenario should be avoided in real network; Chain of rings - when a series of rings are connected through interconnection nodes that are part of both interconnected rings (see Figure 3) /LSR\******/LSR\******/LSR\xxxx/LSR\*****/LSR\******/LSR\ \_C_/ \_B_/ \_A_/ \_6_/ \_1_/ \_2_/ * * x x * * * Ring #1 * x x * Ring #2 * _*_ ___ _*_ x _*_ ___ _*_ /LSR\ /LSR\ /LSR\x x /LSR\ /LSR\ /LSR\ \_D_/******\_E_/******\_F_/xxxx\_5_/*****\_4_/******\_3_/ *** physical link xxx interconnection link Figure 1 Liu & Weingarten Expires October 28, 2012 [Page 3] Internet-Draft MPLS-TP protection April 2012 ___ ___ ___ ___ /LSR\**********/LSR\ /LSR\*********/LSR\ \_C_/ \_B_/* *\_1_/ \_2_/ * * * * * * * * * * * * _*_ * ___ * _*_ /LSR\ Ring #1 /LSR\ Ring #2 /LSR\ \_D_/ *\_A_/* \_3_/ * * * * * * * * * * * * _*_ ___* *___ _*_ /LSR\ /LSR\ /LSR\ /LSR\ \_E_/***********\_F_/ \_5_/**********\_4_/ *** physical link Figure 2 ___ ___ ___ ___ ___ /LSR\******/LSR\******/LSR\*****/LSR\******/LSR\ \_C_/ \_B_/ \_A_/ \_1_/ \_2_/ * x * * Ring #1 x Ring #2 * _*_ ___ _x_ ___ _*_ /LSR\ /LSR\ /LSR\ /LSR\ /LSR\ \_D_/******\_E_/******\_F_/*****\_4_/******\_3_/ *** physical link xxx shared link Liu & Weingarten Expires October 28, 2012 [Page 4] Internet-Draft MPLS-TP protection April 2012 Figure 3 Regarding traffic that traveres more than two rings.the different interconnection scenarios could be mixed. Dual-node and single-node mixed interconnection-when there not only exist two interconnected rings are interconnected by two nodes from each ring. but also there exist two interconnected rings are interconnected by single node( see figure 5); Dual-node and chained mixed interconnection-when there exist two interconnnected rings are interconnected by two nodes from each ring. in addtion, there still exist two interconnnected rings are interconnected by a common chained link(see figure 4); single-node and chained mixed interconnection-when there exist two interconnected rings are interconnected by single node, in addtion, there still exist two interconnected rings are interconnected by a common chained link(see figure 6); Dual-node, single-node and chained mixed interconnection-when there exist all three interconnection scenrios in the network domain including Dual-node interconnnection, single-node interconnection and chained interconnnection( see figure 7); ___ /LSR\******/LSR\xx/LSR\****/LSR\ /LSR\**** /LSR\***/LSR\ \_C_/ \_B_/ \_A_/ \_6_/ \_1_/ \_2_/ \_H_/ * * x x * * * x * x * x * * Ring 1 * x x * Ring 2 * .....*Ring 3 x Ring 4* _*_ *x x_*_ _*_ ___ ___ ___ /LSR\ /LSR\ /LSR\ /LSR\ /LSR\*****/LSR\**/LSR\ \_D_/******\_E_/xx\_5_/*****\_4_/ \_k_/ \_L_/ \_M_/ *** physical link xxx interconnection link Figure 4 Liu & Weingarten Expires October 28, 2012 [Page 5] Internet-Draft MPLS-TP protection April 2012 ___ /LSR\******/LSR\xx/LSR\****/LSR\ /LSR\ /LSR\ \_C_/ \_B_/ \_A_/ \_6_/ \_1_/ *\_H_/ * * x x * * * * * * x * * ___ * * * Ring 1 * x x * Ring 2 * .....*Ring 3/LSR\ Ring 4* _*_ *x x_*_ _*_ ___ * \_L_/* ___ /LSR\ /LSR\ /LSR\ /LSR\ /LSR\* * /LSR\ \_D_/******\_E_/xx\_5_/*****\_4_/ \_k_/ \_M_/ *** physical link xxx interconnection link Figure 5 ___ /LSR\******/LSR\**/LSR\****/LSR\ /LSR\ /LSR\ \_C_/ \_B_/ \_A_/ \_6_/ \_1_/ *\_H_/ * x * * * * * * * ___ * * * Ring 1 x Ring 2 * .....*Ring 3/LSR\ Ring 4* _*_ _ _x_ _*_ ___ * \_L_/* ___ /LSR\ /LSR\ /LSR\ /LSR\ /LSR\* * /LSR\ \_D_/******\_E_/**\_5_/*****\_4_/ \_k_/ *\_M_/ *** physical link xxx interconnection link Figure 6 Liu & Weingarten Expires October 28, 2012 [Page 6] Internet-Draft MPLS-TP protection April 2012 ___ /LSR\******/LSR\xx/LSR\****/LSR\**** /LSR\ /LSR\ \_C_/ \_B_/ \_A_/ \_6_/ \_1_/ *\_H_/ * * x x * x x * * * x x * ___ * * * Ring 1 * x x * Ring 2 xRing 5 xRing 3/LSR\ Ring 4* _*_ *x x_*_ _x_ ___ * \_L_/* ___ /LSR\ /LSR\ /LSR\ /LSR\****/LSR\* * /LSR\ \_D_/******\_E_/xx\_5_/*****\_4_/ \_k_/ *\_M_/ *** physical link xxx interconnection link Figure 7 For a multi-ring service, it will be accross more than one ring just like above seven scenrios. if a failur happens on a multi-ring path, quickly recovery is necessary requirement for MPLS-TP network, so there are describles for recoverying the failure in the multi-ring interconnection sencrios in the following sections . 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: Operations, Administration, Maintenance LSP: Label Switched Path. TLV: Type Length Value P2MP:Point to Multi-Point P2P:Point to Point PSC:Protection Switching Coordination SD:Signal Degrade Liu & Weingarten Expires October 28, 2012 [Page 7] Internet-Draft MPLS-TP protection April 2012 SF:Signal Fail RDI:Remote Defect Indication SPME:Sub-Path Maintenance Entity MPLS-TP:Multi-Protocol Label Switching Transport Profile ME: Maintenance Entity MEP:MEG End Point ACH: Associated Channel Header CC-V: Contunuity Check-Verification; 3. recovery mechanisms This following sections propose different mechanisms that may be used to protect traffic that traverses multiple rings in the different interconnection scenarios. 3.1. recovery mechanism for Dual-node interconnected-ring Under the interconnected-ring scenrio just as figure 1,multi-ring traffic will be transported by interconnection link(LSR C-LSR 6).protecting against a failure on the interconnection link could be based on 1:1 linear protection of the segment from LSR-A to LSR-6 by using the protection path LSR-A to LSR-F to LSR-6. Alternatively, an end-to-end protection path(LSR-C to LSR-2 through D-E-F-5-4-3) could be used to protect all traffic. For the two alternatives, they both have different advantage and disadvantage. 1:1 linear segment protection may be faster than end-to-end protection. but when the interconnection node(LSR-A or LSR-6) has a failure, it maybe need another protection solution to recovery it. but end-to-end protection may protect one or multiple failures on multi-ring working path.in specially, it may protect the failure of interconnection node. . 3.2. recovery mechanism for Chained interconnected-ring For the chained interconnected-ring scenrio, if the interconnection nodes(LSR-A and LSR-F) or the shared link(LSR-A-LSR-F) have failures, protecting each single ring will fail to provide recovery of the failure, so the affected multi-ring traffic should be protected by an end-to-end protection path. . Liu & Weingarten Expires October 28, 2012 [Page 8] Internet-Draft MPLS-TP protection April 2012 3.3. recovery mechanism for Dual-node and Single-node mixed interconnected-ring For the mixed interconnected-ring scenrio, As the single-node interconnection scenario should be avoided. if we only consider segment protection between two rings, the solution is the same as dual-node interconnected-ring. . 3.4. recovery mechanism for Dual-node and Chained mixed interconnected- ring . for the mixed interconnected-ring scenrio, each interconnection nodes or shared interconnection link will be protected by setting up segment protection path seperately. in addition, it may still use end to end multi-ring protection path to protect multiple interconnection nodes or shared interconnection link failure. 3.5. recovery mechanism for Single-node and Chained mixed interconnected-ring for the mixed interconnected-ring scenrios, As the single-node interconnection scenario should be avoided. if we only consider segment protection between two rings, the solution is the same as chained interconnected-ring. 3.6. recovery mechanism for Dual-node ,Single-node and Chained mixed interconnected-ring for the mixed interconnected-ring scenrios, As the single-node interconnection scenario should be avoided. here we can consider the protection solution maybe like solution of dual-node and chained mixed interconnected-ring scenario. 4. Security Considerations TBD 5. IANA Considerations TBD. 6. Acknowledgments TBD . Liu & Weingarten Expires October 28, 2012 [Page 9] Internet-Draft MPLS-TP protection April 2012 7. References 7.1. Normative References [RFC 5654] IETF, "IETF RFC5654(MPLS-TP requirement)", September 2009. [RFC 5921] IETF, "IETF RFC5654(MPLS-TP framework)", July 2010. [RFC 6372] N. Sprecher, A. Farrel, "Multiprotocol Label Switching Transport Profile Survivability Framework", September 2011. [RFC 6378] S. Bryant, N. Sprecher, A. Fulignoli Y. Weingarten, "MPLS transport profile Linear Protection", September 2011. 7.2. Informative References [MPLS-TP Ring Protection] Y. Weingarten, "Multiprotocol Label Switching Transport Profile Ring Protection", Sep 2011. 7.3. URL References [MPLS-TP-22] IETF - ITU-T Joint Working Team, "", 2008, . Authors' Addresses Liu guoman ZTE Corporation No.50, Ruanjian Road, Yuhuatai District Nanjing 210012 P.R.China Phone: +86 025 52871606 Email: liu.guoman@zte.com.cn Liu & Weingarten Expires October 28, 2012 [Page 10] Internet-Draft MPLS-TP protection April 2012 Yaacov Weingarten 34 Hagefen St Karnei Shomron 44853 Israel Phone: +972-9-775 1827 Email: wyaacov@gmail.com Liu & Weingarten Expires October 28, 2012 [Page 11]