Network Working Group L. Ong, Ciena Internet-Draft A. Malis, Verizon Intended status: Standards Track R. Theillaud, Marben Products Expires: January 12, 2011 July 12, 2010 Optimization of GMPLS BW advertisement for SONET/SDH draft-ong-gmpls-ason-routing-exper-02 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 January 12, 2011. Abstract IETF CCAMP WG has defined a set of extensions to OSPFv2 to support ASON routing requirements in [RFC5787]. No extensions were defined for bandwidth advertisement as the Interface Switching Capability Descriptor may optionally be included for each layer of a multi-layer link [RFC4202]. However, for some types SONET/SDH links there can be several data plane layers supported by a single link, and as a result a need to carry several copies of the ISCD. This draft defines an optimization for bandwidth advertisement for SONET/SDH that removes the need to carry multiple copies of the ISCD sub-TLV and has been designed to be consistent with advertisement of bandwidth for OTN. Ong & Theillaud Expires January 12, 2011 [Page 1] Internet-Draft draft-ong-gmpls-ason-routing-exper-01 July 2010 These formats are based on previous experience prototyping and testing control plane for ASON networks and are proposed for adoption as a Standards Track RFC for support of ASON routing. 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 RFC 2119 [RFC2119]. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Optimization of bandwidth advertisement for SONET/SDH. . . . . 3 2.1. Requirements for Multi-layer SONET/SDH Links . . . . . . . 3 2.2. Link Component Availability Sub-TLV. . . . . . . . . . . . 4 3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 4. Security Considerations . . . . . . . . . . . . . . . . . . . 6 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 6 6. References. . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6.1. Normative References. . . . . . . . . . . . . . . . . . . . 6 6.2. Informative References. . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7 Intellectual Property and Copyright Statements . . . . . . . . . . 7 Ong & Theillaud Expires January 12, 2011 [Page 2] Internet-Draft draft-ong-gmpls-ason-routing-exper-02 July 2010 1. Introduction The ITU-T defines the architecture of the Automatically Switched Optical Network (ASON) in [G.8080]. [RFC4258] details the routing requirements for the GMPLS suite of routing protocols to support the capabilities and functionality of ASON control planes identified in [G.7715] and in [G.7715.1]. [RFC4652] evaluates the IETF Link State Routing Protocols against the requirements identified in [RFC4258]. Section 7.1 of [RFC4652] summarizes the capabilities to be provided by OSPFv2 [RFC2328] in support of ASON routing. [RFC5787] is an Experimental RFC that defines extensions to OSPFv2 to support these requirements. It notes that the Interface Switching Capability Descriptor may be included for each layer of a multi-layer link [RFC4202] to meet ASON needs. However, for some types SONET/SDH links there can be several data plane layers supported by a single link, and as a result a need to carry several copies of the ISCD. This draft defines an optimization for bandwidth advertisement for SONET/SDH that removes the need to carry multiple copies of the ISCD sub-TLV and has been designed to be consistent with advertisement of bandwidth for OTN. 2. Optimization of bandwidth advertisement for SONET/SDH 2.1 Requirements for Multi-layer SONET/SDH Links [RFC4652] notes that in the ASON context, bandwidth accounting representations are possible, taking the form of a set of tuples , and that this representation may also require definition of additional signal types (from those defined in [RFC4606]) to represent support of contiguously concatenated signals, i.e., STS-(3xN)c SPE / VC-4-Nc, N = 4, 16, 64, 256. It notes that the ISCD defined in [RFC4202] can be used to support ASON without requiring any bandwidth accounting change from an LSR perspective. However, the ISCD defined in [RFC4202} must be advertised once per signal type (identified by the Minimum Reservable Bandwidth value) in order to provide an accurate advertisement of bandwidth for each signal. For SONET/SDH links, it is common to support 4-5 signal types (e.g., STS-1, 3c, 12c, 48c and 192c) at once, Ong & Theillaud Expires January 12, 2011 [Page 3] Internet-Draft draft-ong-gmpls-ason-routing-exper-02 July 2010 and advertisement of 4-5 ISCD sub-TLVs would consume about 200 bytes as compared to 20-30 bytes for a tuple format. Most of the ISCD bytes are required to advertise 8 levels of priority. We believe this overhead can be reduced as (a) ASON specifications do not identify priority as an ASON service; and (b) TDM networks generally to not support preemption priority and do not require 8 levels of priority. 2.2. Link Component Availability Sub-TLV A Link Component Availability Sub-TLV is defined that carries an indication of SONET/SDH bandwidth at multiple link component signal types as supplementary information to the ISCD sub-TLV. When multiple SONET/SDH signal types are advertised, a single ISCD is given for the smallest bandwidth signal type and the LCA sub-TLV is also advertised to provide compact bandwidth availability advertisement for all signal types. The type used for the sub-TLV is TBD. The following format is defined: 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 (tbd) | Length = 8 + n*4 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Switching Cap | Encoding | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |7|6|5|4|3|2|1|0| Reserved | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Signal Type | Number of Unallocated Timeslots | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Signal Type | Number of Unallocated Timeslots | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // ... // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Signal Type | Number of Unallocated Timeslots | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Note: n defines the number of signal types supported on this link, and thus has a value greater than or equal to 1. Inherited from [RFC4202], the Switching Capability field and the Encoding field MUST take the following values for Sonet/SDH interfaces: Switching Capability (8 bits)=100 (TDM). Encoding (8 bits)=5 (Sonet/SDH). Ong & Theillaud Expires January 12, 2011 [Page 4] Internet-Draft draft-ong-gmpls-ason-routing-exper-02 July 2010 Priority flags (8 bits): Indicate the priorities supported on the advertised link (0 is highest and 7 is lowest). When the flag is set, the corresponding priority is supported and for each signal type, a "row" (i.e. signal type + unreserved bandwidth field) is included, in order from the highest to the lowest priority. If no priority is supported, just the 0 priority MUST be advertised. Signal Type (8 bits) (as defined in [RFC4606]): Value Type (Elementary Signal) ----- ------------------------ 5 STS-1 SPE / VC-3 [RFC4606] 6 STS-3c SPE / VC-4 [RFC4606] TBD STS-12c SPE/VC-4-4c TBD STS-48c SPE/VC-4-16c TBD STS-192c SPE/VC-4-64c Number of Unallocated Timeslots (24 bits): Specifies the number of identical unallocated timeslots per Signal Type and per TE Link. As such, the initial value(s) of this TLV indicates the total capacity in terms of number of timeslots per TE link. The signal type included in the BW announcement is specific to the layer link being reported and is not derived from some other signal type (e.g. STS-48c is not announced as 16 x STS-3c). For instance on an OC-192/STM-64 interface either the number of STS-3c SPE/VC-4 unallocated timeslots is initially equal to 64, or the number of STS-48c SPE/VC-4-16c unallocated timeslots is equal to 4 or even a combination of both type of signals depending on the interface capabilities. Once one of these timeslots is occupied either by being allocated for a connection at the same or a larger signal type or by being blocked due to the allocation of part of the timeslot for a connection at a smaller signal type, the number of unallocated timeslots is decreased by the number of timeslots this connection implies. 3. IANA Considerations IANA will allocate codepoints for the new Link Component Allocation sub-TLV and its associated sub-fields from the standard range. Three new Signal Type values are needed. Ong & Theillaud Expires January 12, 2011 [Page 5] Internet-Draft draft-ong-gmpls-ason-routing-exper-02 July 2010 4. Security Considerations This document defines an optimization for SONET/SDH link bandwidth advertisement consistent with the requirements in [RFC4258] and [RFC4652]. No additional security issues are identified. 5. Acknowledgements The authors would like to thank the following OIF members for their comments and support for this document: Richard Graveman (Department of Defense) Hans-Martin Foisel (Deutsche Telekom) Thierry Marcot (France Telecom) Evelyne Roch (Nortel Networks) Jonathan Sadler (Tellabs) Yoshiaki Sone (NTT Corporation) Takehiro Tsuritani (KDDI R&D Laboratories) 6. References 6.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2328] Moy, J., "OSPF Version 2", RFC 2328,April 1998. [RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering (TE) Extensions to OSPF Version 2", RFC 3630, September 2003. [RFC4202] Kompella, K. and Y. Rekhter, "Routing Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4202,February 2005. [RFC4606] Mannie, E. and D. Papadimitriou, "Generalized Multi- Protocol Label Switching (GMPLS) Extensions for Synchronous Optical Network (SONET) and Synchronous Digital Hierarchy (SDH) Control", RFC 4606, August 2006. 6.2. Informative References [RFC5787] Papadimitriou, D., "OSPFv2 Routing Protocol Extensions for ASON Routing," RFC 5787, March 2010. [RFC4258] Brungard, D., "Requirements for Generalized Multi-Protocol Label Switching (GMPLS) Routing for the Automatically Switched Optical Network (ASON)", RFC 4258, November 2005. [RFC4652] Papadimitriou, D., L.Ong, Sadler, J., Shew, S., and D. Ward, "Evaluation of Existing Routing Protocols against Automatic Switched Optical Network (ASON) Routing Requirements", RFC 4652, February 2006. Ong & Theillaud Expires January 12, 2011 [Page 6] Internet-Draft draft-ong-gmpls-ason-routing-exper-02 July 2010 Authors' Addresses Lyndon Ong Ciena P.O.Box 308 Cupertino CA 95015 USA Phone: +1 408 962 4929 Email: lyong@ciena.com Andrew Malis Verizon 117 West St. Waltham, MA 02451 USA Email: andrew.g.malis@verizon.com Phone: +1 781 466 2362 Remi Theillaud Marben Products 176 rue Jean Jaures Puteaux 92800 France Email: remi.theillaud@marben-products.com Copyright Notice Copyright (c) 2010 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. Ong & Theillaud Expires January 12, 2011 [Page 7]