Network Working Group A. Takacs Internet-Draft F. Fondelli Intended status: Standards Track B. Tremblay Expires: April 25, 2013 Ericsson Z. Ali Cisco Systems October 22, 2012 RSVP-TE Recovery Extension for data plane initiated reversion, protection timer and SNC options signalling draft-takacs-ccamp-revertive-ps-07 Abstract RSVP-TE recovery extensions are specified in [RFC4872] and [RFC4873]. Currently recovery signalling does not support the request for revertive protection, recovery timers values, and sub-network connection (SNC) protection options. This document extends the PROTECTION Object format allowing sub-TLVs, and defines three sub-TLVs to carry wait-to-restore and hold-off intervals and SNC protection options. Takacs, et al. Expires April 25, 2013 [Page 1] Internet-Draft RSVP-TE Recovery Extenison October 2012 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 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 April 25, 2013. Copyright Notice 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. Takacs, et al. Expires April 25, 2013 [Page 2] Internet-Draft RSVP-TE Recovery Extenison October 2012 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Updated PROTECTION Object format and sub-TLVs . . . . . . . . 6 3. Error handling . . . . . . . . . . . . . . . . . . . . . . . . 9 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 5. Security Considerations . . . . . . . . . . . . . . . . . . . 11 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 Takacs, et al. Expires April 25, 2013 [Page 3] Internet-Draft RSVP-TE Recovery Extenison October 2012 1. Introduction Generalised MPLS (GMPLS) extends MPLS to include support for 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. It also does not provide information on the protection switching operation mode (i.e., revertive or non- revertive) and sub-network connection (SNC) protection options. 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 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 and SNC protection options must be accurately configured at both ends of the LSP. Operators may need to tune WTR and HOFF timers on a per LSP basis to ensure best protection switching performance (e.g., account for differential delays between Takacs, et al. Expires April 25, 2013 [Page 4] Internet-Draft RSVP-TE Recovery Extenison October 2012 worker and protection paths). Currently 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 format allowing sub-TLVs, and defines three sub-TLVs to carry WTR and HOFF timer values and SNC protection options. Takacs, et al. Expires April 25, 2013 [Page 5] Internet-Draft RSVP-TE Recovery Extenison October 2012 2. Updated PROTECTION Object format and sub-TLVs 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. The new format updates the PROTECTION Object format of C-Type 2. The updated format is depicted below. IANA is requested to maintain the TLV space for the PROTECTION Object. We retained C-Type to ensure that nodes not capable of interpreting the new format (sub-TLVs) will still be able to process the object without being required to generate an error; while nodes recognising the new format will process the TLVs accordingly. The processed sub- TLV MUST be included in the PROTECTION Object sent in the Resv message upstream, to ensure that the sender can maintain a consistent view of the actual protection configuration of the LSP. 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(2) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |S|P|N|O| Reserved | LSP Flags | Reserved | Link Flags| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |I|R| Reserved | Seg.Flags | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ sub-TLVs ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ This document specifies three new 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Takacs, et al. Expires April 25, 2013 [Page 6] Internet-Draft RSVP-TE Recovery Extenison October 2012 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ SNC protection options sub-TLV specifies attributes of the SNC protection. 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 (3) (IANA) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |mode | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Mode field (3 bits): The mode values are defined as follows: SNC Protection Mode Value ------------------- ----- Reserved 0x0 SNC/N 0x1 (Sub Network Connection protection with Non-intrusive monitoring) SNC/I 0x2 (Sub Network Connection protection with Inherent monitoring) SNC/S 0x3 (Sub Network Connection protection with Sub-layer monitoring) Reserved field (29 bits): This field is reserved for future use. It MUST be set to 0 when sent and MUST be ignored when received. In the case of end-to-end protection the PROTECTION Object is inserted at the top level in the Path message, the WTR, HOFF and SNC Takacs, et al. Expires April 25, 2013 [Page 7] Internet-Draft RSVP-TE Recovery Extenison October 2012 options sub-TLVs 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 and SNC protection optoins 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 April 25, 2013 [Page 8] Internet-Draft RSVP-TE Recovery Extenison October 2012 3. Error handling In the case a specific configuration of the timers or SNC option is not supported the corresponding error should be generated and sent in the PathErr message: "Routing Problem/Unsupported WTR value" or "Routing Problem/Unsupported HOFF value" or "Routing Problem/ Unsupported SNC protection mode". Takacs, et al. Expires April 25, 2013 [Page 9] Internet-Draft RSVP-TE Recovery Extenison October 2012 4. IANA Considerations 4.1. New TLV space for the PROTECTION object A new TLV space needs to be opened and maintained for the PROTECTION Object in the "Class Names, Class Numbers, and Class Types " Registry. 4.3. New RSVP error sub-code For Error Code = 24 "Routing Problem" (see [RFC3209]) the following sub-codes are defined. Sub-code Value -------- ----- Unsupported WTR value To be assigned by IANA (suggest value: 80) Unsupported HOFF value To be assigned by IANA (suggest value: 81) Unsupported SNC protection mode To be assigned by IANA (suggest value: 82) Takacs, et al. Expires April 25, 2013 [Page 10] Internet-Draft RSVP-TE Recovery Extenison October 2012 5. Security Considerations This document introduces no new security issues. The considerations in [RFC4872] and [RFC4873] apply. Takacs, et al. Expires April 25, 2013 [Page 11] Internet-Draft RSVP-TE Recovery Extenison October 2012 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 April 25, 2013 [Page 12] Internet-Draft RSVP-TE Recovery Extenison October 2012 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 Zafar Ali Cisco Systems Email: zali@cisco.com Takacs, et al. Expires April 25, 2013 [Page 13]