Network Working Group Fatai Zhang Internet-Draft Xian Zhang Intended status: Standards Track Huawei Adrian Farrel Old Dog Consulting Oscar Gonzalez de Dios Telefonica D. Ceccarelli Ericsson Expires: May 12, 2014 November 12, 2013 RSVP-TE Signaling Extensions in support of Flexible Grid draft-zhang-ccamp-flexible-grid-rsvp-te-ext-03.txt Abstract This memo describes the extensions to RSVP-TE signaling to support Label Switched Paths in a GMPLS-controlled network that includes devices using the new flexible optical grid. 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 May 12, 2014. Zhang et al Expires May 2014 [Page 1] draft-zhang-ccamp-flexible-grid-rsvp-te-ext-03.txt November 2013 Table of Contents 1. Introduction ................................................ 2 2. Terminology ................................................. 3 2.1. Conventions used in this document .......................3 3. Requirements for Flexible Grid Signaling .....................3 3.1. Slot Width ............................................. 4 3.2. Frequency Slot ......................................... 4 4. Protocol Extensions ......................................... 5 4.1. Traffic Parameters...................................... 5 4.1.1. Applicability to Fixed Grid Networks ...............6 4.2. Generalized Label....................................... 6 4.3. Signaling Procedures.................................... 6 5. IANA Considerations ......................................... 7 5.1. RSVP Objects Class Types................................ 7 6. Manageability Considerations................................. 7 7. Security Considerations...................................... 7 8. References .................................................. 8 8.1. Normative References.................................... 8 8.2. Informative References.................................. 8 9. Contributors' Address........................................ 8 10. Authors' Addresses ..........................................9 1. Introduction [G.694.1] defines the Dense Wavelength Division Multiplexing (DWDM) frequency grids for Wavelength Division Multiplexing (WDM) applications. A frequency grid is a reference set of frequencies used to denote allowed nominal central frequencies that may be used for defining applications. The channel spacing is the frequency spacing between two allowed nominal central frequencies. All of the wavelengths on a fiber use different central frequencies and occupy a fixed bandwidth of frequency. Fixed grid channel spacing is selected from 12.5 GHz, 25 GHz, 50 GHz, 100 GHz and integer multiples of 100 GHz. But [G.694.1] also defines "flexible grids", known as "flexi-grid". The terms "frequency slot (i.e. the frequency range allocated to a specific channel and unavailable to other channels within a flexible grid)" and "slot width" (i.e. the full width of a frequency slot in a flexible grid) are introduced to define a flexible grid. [FLEX-FWK] defines a framework and the associated control plane requirements for the GMPLS based control of flexi-grid DWDM networks. Zhang Expires May 2014 [Page 2] draft-zhang-ccamp-flexible-grid-rsvp-te-ext-03.txt November 2013 [RFC6163] provides a framework for GMPLS and Path Computation Element (PCE) control of Wavelength Switched Optical Networks (WSONs), and [WSON-SIG] describes the requirements and protocol extensions for signaling to set up Label Switched Paths (LSPs) in WSONs. This document describes the additional requirements and protocol extensions for signaling to set up LSPs in networks that support the flexi-grid. 2. Terminology For terminology related to flexi-grid, please refer to [FLEX-FWK] and [G.694.1]. 2.1. 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 [RFC2119]. 3. Requirements for Flexible Grid Signaling The architecture for establishing LSPs in a flexi-grid network is described in [FLEX-FWK]. A optical spectrum LSP occupies a specific frequency slot, i.e. a range of frequencies. The process of computing a route and the allocation of a frequency slot is referred to as RSA (Routing and Spectrum Assignment). [FLEX-FWK] describes three types of architecture approaches to RSA: combined RSA, separated RSA and distributed SA. The first two approaches are referred to as "centralized SA", because both routing and spectrum (frequency slot) assignment are performed by centralized entity before the signaling procedure. In the case of centralized SA, the assigned frequency slot is specified in the Path message during LSP setup. In the case of distributed SA, the slot width of the flexi-grid LSP is specified in the Path message, allowing the involved network elements to select the frequency slot to be used. If the capability of switching or converting the whole optical spectrum allocated to an optical spectrum LSP is not available at nodes along the path of the LSP, the LSP is subject to the Optical "Spectrum Continuity Constraint", as described in [FLEX-FWK]. Zhang Expires May 2014 [Page 3] draft-zhang-ccamp-flexible-grid-rsvp-te-ext-03.txt November 2013 The remainder of this section states the additional requirements for signaling in a flexi-grid network. 3.1. Slot Width The slot width is an end-to-end parameter representing how much frequency resource is requested for a flexi-grid LSP. It is equivalent of optical bandwidth, although the amount of bandwidth associated with a slot width will depend on the encoding. Different LSPs may request different amounts of frequency resource in flexible grid networks, so the slot width needs to be carried in the signaling message during LSP establishment. This enables the nodes along the LSP to know how much frequency resource has been requested (in a Path message) and has been allocated (by a Resv message) for the LSP. 3.2. Frequency Slot The frequency slot information identifies which part of the frequency spectrum is allocated on each link for a flexi-LSP. This information is required in Resv message to indicate, hop-by-hop, the central frequency of the allocated resource. In combination with the slot width indicated in a Resv message (see Section 3.1) the central frequency carried in a Resv message identifies the resources reserved for the LSP (known as the frequency slot). The frequency slot can be represented by the two parameters as follows: Frequency slot = [(central frequency) - (slot width)/2] ~ [(central frequency) + (slot width)/2] As is common with other resource identifiers (i.e., labels) in GMPLS signaling, it must be possible for the head-end LSP to suggest or require the central frequency to be used for the LSP. Furthermore, for bidirectional LSPs, the Path message must be able to specify the central frequency to be used for reverse direction traffic. As described in [G.694.1], the allowed frequency slots for the flexible DWDM grid have a nominal central frequency (in THz) defined by: 193.1 + n * 0.00625 where n is zero or a positive or negative integer. Zhang Expires May 2014 [Page 4] draft-zhang-ccamp-flexible-grid-rsvp-te-ext-03.txt November 2013 The slot width (in GHz) is defined as: 12.5 * m where m is a positive integer. It is possible that implementing a subset of the possible slot widths and central frequencies are supported. For example, an implementation could built where the nominal central frequency granularity is 12.5 GHz (by only requiring values of n that are even) and that only supports slot widths as a multiple of 25 GHz (by only allowing values of m that are even). Further details can be found in [FLEX-FWK]. 4. Protocol Extensions This section defines the extensions to RSVP-TE signaling for GMPLS [RFC3473] to support flexible grid networks. 4.1. Traffic Parameters In RSVP-TE, the SENDER_TSPEC object in the Path message indicates the requested resource reservation. The FLOWSPEC object in the Resv message indicates the actual resource reservation. As described in Section 3.1, the slot width represents how much frequency resource is requested for a flexi-grid LSP. That is, it describes the end-to-end traffic profile of the LSP. Therefore, the traffic parameters for a flexi-grid LSP encode the slot width. This document defines new C-Types for the SENDER_TSPEC and FLOWSPEC objects to carry Spectrum Switched Optical Network (SSON) traffic parameters: SSON SENDER_TSPEC: Class = 12, C-Type = TBD1. SSON FLOWSPEC: Class = 9, C-Type = TBD2. The SSON traffic parameters carried in both objects have the same format as shown in Figure 1. Zhang Expires May 2014 [Page 5] draft-zhang-ccamp-flexible-grid-rsvp-te-ext-03.txt November 2013 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | m | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: The SSON Traffic Parameters m (8 bits): the slot width is specified by m*12.5 GHz. The Reserved bits MUST be set to zero and ignored upon receipt. 4.1.1. Applicability to Fixed Grid Networks Note that the slot width (i.e., traffic parameters) of a fixed grid defined in [G.694.1] can also be specified by using the SSON traffic parameters. The fixed grid channel spacings (12.5 GHz, 25 GHz, 50 GHz, 100 GHz and integer multiples of 100 GHz) are also the multiple of 12.5 GHz, so the m parameter can be used to represent these slot widths. Therefore, it is possible to consider using the new traffic parameter object types in common signaling messages for flexi-grid and legacy DWDM networks. 4.2. Generalized Label In the case of a flexible grid network, the labels that have been requested or allocated as signaled in the RSVP-TE objects are encoded as described in [FLEX-LBL]. This new label encoding can appear in any RSVP-TE object or sub-object that can carry a label. As noted in Section 4.2 of [FLEX-LBL], the m parameter forms part of the label as well as part of the traffic parameters. 4.3. Signaling Procedures There are no differences between the signaling procedure described for LSP control in [FLEX-FWK] and those required for use in a fixed- grid network [WSON-SIG]. Obviously, the TSpec, FlowSpec and label formats described in Section 3 are used. The signaling procedures for distributed SA and centralized SA can be applied. Zhang Expires May 2014 [Page 6] draft-zhang-ccamp-flexible-grid-rsvp-te-ext-03.txt November 2013 5. IANA Considerations 5.1. RSVP Objects Class Types This document introduces two new Class Types for existing RSVP objects. IANA is requested to make allocations from the "Resource ReSerVation Protocol (RSVP) Parameters" registry using the "Class Names, Class Numbers, and Class Types" sub-registry. Class Number Class Name Reference ------------ ----------------------- --------- 9 FLOWSPEC [RFC2205] Class Type (C-Type): (TBD2) SSON FLOWSPEC [This.I-D] Class Number Class Name Reference ------------ ----------------------- --------- 12 SENDER_TSPEC [RFC2205] Class Type (C-Type): (TBD1) SSON SENDER_TSPEC [This.I-D] IANA is requested to assign the same value for TBD1 and TBD2, and a value of 8 is suggested. 6. Manageability Considerations This document makes minor modifications to GMPLS signaling, but does not change the manageability considerations for such networks. Clearly, protocol analysis tools and other diagnostic aids (including logging systems and MIB modules) will need to be enhanced to support the new traffic parameters and label formats. 7. Acknowledgments This work was supported in part by the FP-7 IDEALIST project under grant agreement number 317999. 8. Security Considerations This document introduces no new security considerations to [RFC3473]. Zhang Expires May 2014 [Page 7] draft-zhang-ccamp-flexible-grid-rsvp-te-ext-03.txt November 2013 9. References 9.1. Normative References [RFC2119] S. Bradner, "Key words for use in RFCs to indicate requirements levels", RFC 2119, March 1997. [RFC3473] L. Berger, Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol- Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. [G.694.1] ITU-T Recommendation G.694.1 (revision 2), "Spectral grids for WDM applications: DWDM frequency grid", February 2012. [FLEX-LBL]King, D., Farrel, A. and Y. Li, "Generalized Labels for the Flexi-Grid in Lambda Switched Capable (LSC) Label Switching Routers", draft-farrkingel-ccamp-flexigrid- lambda-label, work in progress. 9.2. Informative References [RFC2205] Braden, R., Zhang L., Berson, S., Herzog, S. and S. Jamin, "Resource ReServation Protocol (RSVP) - Version 1, Functional Specification', RFC2205, September 1997. [RFC6163] Y. Lee, G. Bernstein and W. Imajuku, "Framework for GMPLS and Path Computation Element (PCE) Control of Wavelength Switched Optical Networks (WSONs)", RFC 6163, April 2011. [FLEX-FWK] Gonzalez de Dios, O,, Casellas R., Zhang, F., Fu, X., Ceccarelli, D., and I. Hussain, "Framework and Requirements for GMPLS based control of Flexi-grid DWDM networks', draft-ogrcetal-cammp-flexi-grid-fwk, work in progress. [WSON-SIG] G. Bernstein, Sugang Xu, Y. Lee, G. Martinelli and Hiroaki Harai, "Signaling Extensions for Wavelength Switched Optical Networks", draft-ietf-ccamp-wson- signaling, work in progress. 10. Contributors' Address Ramon Casellas CTTC Av. Carl Friedrich Gauss n7 Castelldefels, Barcelona 08860 Zhang Expires May 2014 [Page 8] draft-zhang-ccamp-flexible-grid-rsvp-te-ext-03.txt November 2013 Spain Email: ramon.casellas@cttc.es Felipe Jimenez Arribas Telefonica Investigacion y Desarrollo Emilio Vargas 6 Madrid, 28045 Spain Email: felipej@tid.es Yi Lin Huawei Technologies Co., Ltd. F3-5-B R&D Center, Huawei Base, Bantian, Longgang District Shenzhen 518129 P.R.China Phone: +86-755-28972914 Email: yi.lin@huawei.com 11. Authors' Addresses Fatai Zhang Huawei Technologies Email: zhangfatai@huawei.com Xian Zhang Huawei Technologies Email: zhang.xian@huawei.com Adrian Farrel Old Dog Consulting Email: adrian@olddog.co.uk Oscar Gonzalez de Dios Telefonica Investigacion y Desarrollo Emilio Vargas 6 Madrid, 28045 Spain Phone: +34 913374013 Email: ogondio@tid.es Daniele Ceccarelli Ericsson Via A. Negrone 1/A Zhang Expires May 2014 [Page 9] draft-zhang-ccamp-flexible-grid-rsvp-te-ext-03.txt November 2013 Genova - Sestri Ponente Italy Email: daniele.ceccarelli@ericsson.com Intellectual Property The IETF Trust takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in any IETF Document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. 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