Network Working Group A. Takacs Internet-Draft F. Fondelli Intended status: Standards Track B. Tremblay Expires: May 7, 2009 Ericsson November 3, 2008 GMPLS RSVP-TE recovery extension for data plane initiated reversion draft-takacs-ccamp-revertive-ps-02 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of 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 May 7, 2009. Takacs, et al. Expires May 7, 2009 [Page 1] Internet-Draft GMPLS revertive protection signalling November 2008 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 defines two new fields in the PROTECTION Object to specify wait-to-restore and hold-off intervals. Takacs, et al. Expires May 7, 2009 [Page 2] Internet-Draft GMPLS revertive protection signalling November 2008 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 . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. PROTECTION object extension . . . . . . . . . . . . . . . . . 6 3. Error handling . . . . . . . . . . . . . . . . . . . . . . . . 7 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 5. Security Considerations . . . . . . . . . . . . . . . . . . . 9 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11 Intellectual Property and Copyright Statements . . . . . . . . . . 12 Takacs, et al. Expires May 7, 2009 [Page 3] Internet-Draft GMPLS revertive protection signalling November 2008 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 disregarding 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 May 7, 2009 [Page 4] Internet-Draft GMPLS revertive protection signalling November 2008 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 adds two new fields to the PROTECTION Object to carry WTR and HOFF values. Takacs, et al. Expires May 7, 2009 [Page 5] Internet-Draft GMPLS revertive protection signalling November 2008 2. PROTECTION object extension In [RFC4872] and [RFC4873] the PROTECTION object is specified to support end-to-end and segment recovery. Two new fields are defined WTR and HOFF. This is depicted below. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |S|P|N|O| Reserved | LSP Flags | Reserved | Link Flags| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |I|R| Reserved | Seg.Flags | Resv. | WTR | HOFF | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ WTR - Wait-to-Restore time field specifies the WTR time. If the WTR field is 0 the protection switching operation modes is non-revertive, otherwise revertive operation with the signalled timer is requested. 9 values for WTR are permitted: WTR value timer -------------------------------- 0 non-revertive mode 1 5min 2-7 6-11min in 1min steps 8 12min HOFF - Hold-off time field specifies the HOFF time. The following values are permitted: HOFF value timer ------------------------------------------- 0 no HOFF 1 100ms 2-99 200ms-9900ms with 100ms steps 100 10sec In order to ensure that the new fields are properly handled by the nodes a new C-Type (3, IANA to assigned) is used to explicitly indicate the presence of WTR and HOFF fields. 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 May 7, 2009 [Page 6] Internet-Draft GMPLS revertive protection signalling November 2008 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 May 7, 2009 [Page 7] Internet-Draft GMPLS revertive protection signalling November 2008 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 May 7, 2009 [Page 8] Internet-Draft GMPLS revertive protection signalling November 2008 5. Security Considerations This document introduces no new security issues. The considerations in [RFC4872] and [RFC4873] apply. Takacs, et al. Expires May 7, 2009 [Page 9] Internet-Draft GMPLS revertive protection signalling November 2008 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 May 7, 2009 [Page 10] Internet-Draft GMPLS revertive protection signalling November 2008 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 May 7, 2009 [Page 11] Internet-Draft GMPLS revertive protection signalling November 2008 Full Copyright Statement Copyright (C) The IETF Trust (2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Takacs, et al. Expires May 7, 2009 [Page 12]