Network Working Group A. Takacs Internet-Draft F. Fondelli Intended status: Standards Track B. Tremblay Expires: September 10, 2009 Ericsson March 9, 2009 GMPLS RSVP-TE recovery extension for data plane initiated reversion draft-takacs-ccamp-revertive-ps-03 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 10, 2009. Takacs, et al. Expires September 10, 2009 [Page 1] Internet-Draft GMPLS revertive protection signalling March 2009 Copyright Notice Copyright (c) 2009 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. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Takacs, et al. Expires September 10, 2009 [Page 2] Internet-Draft GMPLS revertive protection signalling March 2009 Abstract GMPLS RSVP-TE recovery extensions are specified in [RFC4872] and [RFC4873]. Currently these extensions cannot signal request for revertive protection neither values for the associated timers to the remote endpoint. This document extends the PROTECTION Object allowing sub-TLVs, and defines two sub-TLVs to carry wait-to-restore and hold-off intervals. Takacs, et al. Expires September 10, 2009 [Page 3] Internet-Draft GMPLS revertive protection signalling March 2009 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 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. PROTECTION object extension . . . . . . . . . . . . . . . . . 7 3. Error handling . . . . . . . . . . . . . . . . . . . . . . . . 9 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 5. Security Considerations . . . . . . . . . . . . . . . . . . . 11 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 Intellectual Property and Copyright Statements . . . . . . . . . . 14 Takacs, et al. Expires September 10, 2009 [Page 4] Internet-Draft GMPLS revertive protection signalling March 2009 1. Introduction Generalised MPLS (GMPLS) extends MPLS to include support of different switching technologies [RFC3471]. These switching technologies provide several protection schemes [RFC4426][RFC4427] (e.g. 1+1, 1:N, M:N). Many characteristics of those protection schemes are common disregard of the switching technology (e.g. TDM, LSC, etc). GMPLS RSVP-TE signalling has been extended to support the various protection schemes and establish connections (Label Switched Paths (LSPs)) configuring its specific protection characteristics [RFC4426][RFC4872]. Currently RSVP-TE extensions do not address the configuration of protection switching timers neither provide information on the protection switching operation mode (i.e., revertive or non- revertive). The Hold-off time (HOFF) is defined as the time between the reporting of signal fail or degrade, and the initialization of the recovery switching operation [RFC4427]. This timer is useful to limit the number of switch actions when multiple layers of recovery are being used, or in case of 1+1 unidirectional protection scheme [G.808.1] to prevent too early switching due to the differential delay difference between the short and long path. The Wait-to-Restore time (WTR) is defined as a period of time that must elapse after a recovered fault before an LSP can be used again to transport the normal traffic and/or to select the normal traffic from the LSP [RFC4427]. The WTR time is fundamental in revertive mode of operation, to prevent frequent operation of the protection switch due to an intermittent defect [G.808.1]. Reversion refers to the process of moving normal traffic back to the original working LSP after the failure is cleared and the path is repaired [RFC4426][RFC4427][RFC4872]. In transport networks reversion is desirable since the protection path may not be optimal from a routing and resource consumption point of view, additionally, moving traffic back to the working LSP allows the protection resources to be used to protect other LSPs. On the other hand, reversion requires that the working resources remain allocated during failure. The operator needs to have the choice between revertive and non-revertive protection to balance the pros and cons in a given situation. WTR and HOFF timers must be accurately configured at both ends of the LSP. Operators may need to tune these timers on a per LSP basis to ensure best protection switching performance (e.g., account for differential delays between worker and protection paths). Currently Takacs, et al. Expires September 10, 2009 [Page 5] Internet-Draft GMPLS revertive protection signalling March 2009 these values are either pre-configured to a default value (and so may be suboptimal for some of the LSPs) or need to be manually set/tuned after the connections have been established. Since these parameters are important for recovery in transport networks, it is desirable that GMPLS RSVP-TE protection signalling carries the necessary information. This document extends the PROTECTION Object allowing sub-TLVs, and defines sub-TLVs to carry WTR and HOFF values. Takacs, et al. Expires September 10, 2009 [Page 6] Internet-Draft GMPLS revertive protection signalling March 2009 2. PROTECTION object extension In [RFC4872] and [RFC4873] the PROTECTION object is specified to support end-to-end and segment recovery. In order to ease addition of protection attributes the PROTECTION Object is extended to carry sub-TLVs. This is depicted below. A new C-Type (3 IANA to assign) is allocated for the new format. This document specifies two new sub-TLVs. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Length | Class-Num(37) | C-Type(3 IANA)| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |S|P|N|O| Reserved | LSP Flags | Reserved | Link Flags| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ sub-TLVs ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ WTR - Wait-to-Restore time sub-TLV specifies the WTR time. If the WTR field is 0 the protection switching operation mode is non- revertive, otherwise revertive operation with the signalled timer (in milliseconds) is requested. The value 0xffffffff is reserved, and refers to a locally pre-configured WTR value. 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 (1) (IANA) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | WTR | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ HOFF - Hold-off time sub-TLV specifies the HOFF time. The values are in milliseconds. The value 0xffffffff is reserved, and refers to a locally pre-configured HOFF value. 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 (2) (IANA) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | HOFF | Takacs, et al. Expires September 10, 2009 [Page 7] Internet-Draft GMPLS revertive protection signalling March 2009 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ In the case of end-to-end protection the PROTECTION Object is inserted at the top level in the Path message, the WTR and HOFF fields correspond to the end-to-end protection. In the case when a segment of the LSP is to be protected and the WTR and HOFF timers for the protection segment are to be set by signalling, explicit segment recovery control has to be used, i.e., the PROTECTION Object with the desired timers set must be inserted in the appropriate Secondary Explicit Route Object (SERO). Takacs, et al. Expires September 10, 2009 [Page 8] Internet-Draft GMPLS revertive protection signalling March 2009 3. Error handling In the case a specific configuration of the timers is not supported the corresponding error should be generated and sent in the PathErr message: "Routing Problem/Unsupported WTR value" and/or "Routing Problem/Unsupported HOFF value". Takacs, et al. Expires September 10, 2009 [Page 9] Internet-Draft GMPLS revertive protection signalling March 2009 4. IANA Considerations A new C-Type (3) is to be assigned for the modified PROTECTION Object in the "Class Names, Class Numbers, and Class Types " Registry. New error values need to be added to "Error Codes and Globally- Defined Error Value Sub-Codes " Registry for the "Routing Problem" Error Code: "Unsupported WTR value" and "Unsupported HOFF value". Takacs, et al. Expires September 10, 2009 [Page 10] Internet-Draft GMPLS revertive protection signalling March 2009 5. Security Considerations This document introduces no new security issues. The considerations in [RFC4872] and [RFC4873] apply. Takacs, et al. Expires September 10, 2009 [Page 11] Internet-Draft GMPLS revertive protection signalling March 2009 6. References [G.808.1] "Generic protection switching -- Linear trail and subnetwork protection", ITU-T Recommendation G.808.1, March 2006. [IEEE-PBBTE] "IEEE 802.1Qay Draft Standard for Provider Backbone Bridging Traffic Engineering", work in progress. [RFC3471] "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description", RFC 3471, January 2003. [RFC4426] "Generalized Multi-Protocol Label Switching (GMPLS) Recovery Functional Specification", RFC 4426, March 2006. [RFC4427] "Recovery (Protection and Restoration) Terminology for Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4427, March 2006. [RFC4872] "RSVP-TE Extensions in Support of End-to-End Generalized Multi-Protocol Label Switching (GMPLS) Recovery", RFC 4872, May 2007. [RFC4873] "GMPLS Segment Recovery", RFC 4873, May 2007. Takacs, et al. Expires September 10, 2009 [Page 12] Internet-Draft GMPLS revertive protection signalling March 2009 Authors' Addresses Attila Takacs Ericsson Laborc u. 1. Budapest, 1037 Hungary Email: attila.takacs@ericsson.com Francesco Fondelli Ericsson Via Negrone Genova, 16153 Italy Email: francesco.fondelli.ericsson.com Benoit Tremblay Ericsson 8400 Decarie. Montreal, Quebec H4P 2N2 Canada Email: benoit.c.tremblay@ericsson.com Takacs, et al. Expires September 10, 2009 [Page 13] Internet-Draft GMPLS revertive protection signalling March 2009 Takacs, et al. Expires September 10, 2009 [Page 14]