Network Working Group G. Bernstein Internet Draft Grotto Networking Intended status: Standards Track Sugang Xu NICT Expires: September 2012 Y.Lee Huawei G. Martinelli Cisco Hiroaki Harai NICT March 7, 2012 Signaling Extensions for Wavelength Switched Optical Networks draft-ietf-ccamp-wson-signaling-03.txt Abstract This memo provides extensions to Generalized Multi-Protocol Label Switching (GMPLS) signaling for control of wavelength switched optical networks (WSON). Such extensions are necessary in WSONs under a number of conditions including: (a) when optional processing, such as regeneration, must be configured to occur at specific nodes along a path, (b) where equipment must be configured to accept an optical signal with specific attributes, or (c) where equipment must be configured to output an optical signal with specific attributes. In addition this memo provides mechanisms to support distributed wavelength assignment with bidirectional LSPs, and choice in distributed wavelength assignment algorithms. These extensions build on previous work for the control of lambda and G.709 based networks. 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 Expires September 7, 2012 [Page 1] Internet-Draft WSON Signaling Extensions March 2012 The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on September 7, 2012. 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. 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 [RFC2119]. Table of Contents 1. Introduction...................................................3 2. Terminology....................................................3 3. Requirements for WSON Signaling................................4 3.1. WSON Signal Characterization..............................4 3.2. Per LSP Network Element Processing Configuration..........5 3.3. Bi-Directional WSON LSPs..................................5 3.4. Distributed Wavelength Assignment Support.................6 3.5. Out of Scope..............................................6 4. WSON Signal Traffic Parameters, Attributes and Processing......6 4.1. Traffic Parameters for Optical Tributary Signals..........6 4.2. Signal Attributes and Processing..........................7 4.2.1. WSON Processing Object Encoding......................8 5. Bidirectional Lightpath Setup..................................8 6. RWA Related....................................................9 6.1. Wavelength Assignment Method Selection....................9 7. Security Considerations.......................................10 Bernstein et al. Expires September 7, 2012 [Page 2] Internet-Draft WSON Signaling Extensions March 2012 8. IANA Considerations...........................................11 9. Acknowledgments...............................................11 10. References...................................................12 10.1. Normative References....................................12 10.2. Informative References..................................12 Author's Addresses...............................................14 Intellectual Property Statement..................................15 Disclaimer of Validity...........................................16 1. Introduction This memo provides extensions to Generalized Multi-Protocol Label Switching (GMPLS) signaling for control of wavelength switched optical networks (WSON). Fundamental extensions are given to permit simultaneous bi-directional wavelength assignment while more advanced extensions are given to support the networks described in [RFC6163] which feature connections requiring configuration of input, output, and general signal processing capabilities at a node along a LSP These extensions build on previous work for the control of lambda and G.709 based networks. 2. Terminology CWDM: Coarse Wavelength Division Multiplexing. DWDM: Dense Wavelength Division Multiplexing. FOADM: Fixed Optical Add/Drop Multiplexer. ROADM: Reconfigurable Optical Add/Drop Multiplexer. A reduced port count wavelength selective switching element featuring ingress and egress line side ports as well as add/drop side ports. RWA: Routing and Wavelength Assignment. Wavelength Conversion/Converters: The process of converting an information bearing optical signal centered at a given wavelength to one with "equivalent" content centered at a different wavelength. Wavelength conversion can be implemented via an optical-electronic- optical (OEO) process or via a strictly optical process. WDM: Wavelength Division Multiplexing. Bernstein et al. Expires September 7, 2012 [Page 3] Internet-Draft WSON Signaling Extensions March 2012 Wavelength Switched Optical Networks (WSON): WDM based optical networks in which switching is performed selectively based on the center wavelength of an optical signal. AWG: Arrayed Waveguide Grating. OXC: Optical Cross Connect. Optical Transmitter: A device that has both a laser tuned on certain wavelength and electronic components, which converts electronic signals into optical signals. Optical Responder: A device that has both optical and electronic components. It detects optical signals and converts optical signals into electronic signals. Optical Transponder: A device that has both an optical transmitter and an optical responder. Optical End Node: The end of a wavelength (optical lambdas) lightpath in the data plane. It may be equipped with some optical/electronic devices such as wavelength multiplexers/demultiplexer (e.g. AWG), optical transponder, etc., which are employed to transmit/terminate the optical signals for data transmission. 3. Requirements for WSON Signaling The following requirements for GMPLS based WSON signaling are in addition to the functionality already provided by existing GMPLS signaling mechanisms. 3.1. WSON Signal Characterization WSON signaling MUST convey sufficient information characterizing the signal to allow systems along the path to determine compatibility and perform any required local configuration. Examples of such systems include intermediate nodes (ROADMs, OXCs, Wavelength converters, Regenerators, OEO Switches, etc...), links (WDM systems) and end systems (detectors, demodulators, etc...). The details of any local configuration processes are out of the scope of this document. From [RFC6163] we have the following list of WSON signal characteristic information: Bernstein et al. Expires September 7, 2012 [Page 4] Internet-Draft WSON Signaling Extensions March 2012 List 1. WSON Signal Characteristics 1. Optical tributary signal class (modulation format). 2. FEC: whether forward error correction is used in the digital stream and what type of error correcting code is used 3. Center frequency (wavelength) 4. Bit rate 5. G-PID: General Protocol Identifier for the information format The first three items on this list can change as a WSON signal traverses a network with regenerators, OEO switches, or wavelength converters. An ability to control wavelength conversion already exists in GMPLS signaling along with the ability to share client signal type information (G-PID). In addition, bit rate is a standard GMPLS signaling traffic parameter. It is referred to as Bandwidth Encoding in [RFC3471]. This leaves two new parameters: modulation format and FEC type, needed to fully characterize the optical signal. 3.2. Per LSP Network Element Processing Configuration In addition to configuring a network element (NE) along an LSP to input or output a signal with specific attributes, we may need to signal the NE to perform specific processing, such as 3R regeneration, on the signal at a particular NE. In [RFC6163] we discussed three types of processing not currently covered by GMPLS: (A) Regeneration (possibly different types) (B) Fault and Performance Monitoring (C) Attribute Conversion The extensions here MUST provide for the configuration of these types of processing at nodes along an LSP. 3.3. Bi-Directional WSON LSPs WSON signaling MAY support LSP setup consistent with the wavelength continuity constraint for bi-directional connections. The following cases MAY be separately supported: Bernstein et al. Expires September 7, 2012 [Page 5] Internet-Draft WSON Signaling Extensions March 2012 (a) Where the same wavelength is used for both upstream and downstream directions (b) Where different wavelengths can be used for both upstream and downstream directions. (Editor's Note: an evaluation of current GMPLS bidirectional solutions should be evaluated if they would fit to the current WSON needs.) 3.4. Distributed Wavelength Assignment Support WSON signaling MAY support the selection of a specific distributed wavelength assignment method. This method is beneficial in cases of equipment failure, etc., where fast provisioning used in quick recovery is critical to protect carriers/users against system loss. This requires efficient signaling which supports distributed wavelength assignment, in particular when the centralized wavelength assignment capability is not available. As discussed in the [RFC6163] different computational approaches for wavelength assignment are available. One method is the use of distributed wavelength assignment. This feature would allow the specification of a particular approach when more than one is implemented in the systems along the path. 3.5. Out of Scope This draft does not address signaling information related to optical impairments. 4. WSON Signal Traffic Parameters, Attributes and Processing As discussed in [RFC6163] single channel optical signals used in WSONs are called "optical tributary signals" and come in a number of classes characterized by modulation format and bit rate. Although WSONs are fairly transparent to the signals they carry, to ensure compatibility amongst various networks devices and end systems it can be important to include key lightpath characteristics as traffic parameters in signaling [RFC6163]. 4.1. Traffic Parameters for Optical Tributary Signals In [RFC3471] we see that the G-PID (client signal type) and bit rate (byte rate) of the signals are defined as parameters and in Bernstein et al. Expires September 7, 2012 [Page 6] Internet-Draft WSON Signaling Extensions March 2012 [RFC3473] they are conveyed Generalized Label Request object and the RSVP SENDER_TSPEC/FLOWSPEC objects respectively. 4.2. Signal Attributes and Processing Section 3.2. gave the requirements for signaling to indicate to a particular NE along an LSP what type of processing to perform on an optical signal or how to configure that NE to accept or transmit an optical signal with particular attributes. One way of accomplishing this is via a new EXPLICIT_ROUTE subobject. Reference [RFC3209] defines the EXPLICIT_ROUTE object (ERO) and a number of subobjects, while reference [RFC5420] defines general mechanisms for dealing with additional LSP attributes. Although reference [RFC5420] defines a RECORD_ROUTE object (RRO) attributes subobject, it does not define an ERO subobject for LSP attributes. Regardless of the exact coding for the ERO subobject conveying the input, output, or processing instructions. This new "processing" subobject would follow a subobject containing the IP address, or the interface identifier [RFC3477], associated with the link on which it is to be used along with any label subobjects [RFC3473]. The WSON Signal Processing object is defined as an LSP_ATTRIBUTES and extends the PATH message. It is defined as the following: ::= [] ::= ::= (ModulationTypeList> Where: : Ipv4,Ipv6 address. Note: this not required if WSON Processing object become part of the ERO is defined in [WSON-Encode]. is defined in [WSON-Encode]. Bernstein et al. Expires September 7, 2012 [Page 7] Internet-Draft WSON Signaling Extensions March 2012 is defined in[WSON-Encode] is defined in [WSON-Encode] is defined in [WSON-Encode] is defined in [WSON-Encode] are only applied in the intermediate nodes of the LSP. The head and tail nodes will ignore regeneration capability processing. 4.2.1. WSON Processing Object Encoding 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 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | ~ Value ~ | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type: to be defined by IANA Value: sub-TLVS according to section 4.1. 5. Bidirectional Lightpath Setup With the wavelength continuity constraint in CI-incapable [RFC3471] WSONs, where the nodes in the networks cannot support wavelength conversion, the same wavelength on each link along a unidirectional lightpath should be reserved. In addition to the wavelength Bernstein et al. Expires September 7, 2012 [Page 8] Internet-Draft WSON Signaling Extensions March 2012 continuity constraint, requirement 3.2 gives us another constraint on wavelength usage in data plane, in particular, it requires the same wavelength to be used in both directions. [RFC6163] in section 6.1 reports on the implication to GMPLS signaling related to both bi-directionality and Distributed Wavelengths Assignment. Current GMPLS solution defines a bidirectional LSP (as defined by [RFC3471]). The label distribution is based on Label_Set and Upstream_Label objects. In case of specific constraints such as the same wavelengths in both directions, it may require several signaling attempts using information from the Acceptable_Label_Set received from path error messages. Some implementations may prefer using two unidirectional LSPs. This solution has been always available as per [RFC3209] however recent work introduces the association concept [RFC4872] and [ASSOC-Info]. Recent transport evolutions [ASSOC-ext] provide a way to associate two unidirectional LSPs as a bidirectional LSP. In line with this, a small extension can make this approach work for the WSON case. 6. RWA Related 6.1. Wavelength Assignment Method Selection Routing + Distributed wavelength assignment (R+DWA) is one of the options defined by the [RFC6163]. The output from the routing function will be a path but the wavelength will be selected on a hop-by-hop basis. Under this hypothesis the node initiating the signaling process needs to declare its own wavelength availability (through a label_set object). Each intermediate node may delete some labels due to connectivity constraints or its own assignment policy. At the end, the destination node has to make the final decision on the wavelength assignment among the ones received through the signaling process. As discussed in [HZang00] a number of different wavelength assignment algorithms maybe employed. In addition as discussed in Bernstein et al. Expires September 7, 2012 [Page 9] Internet-Draft WSON Signaling Extensions March 2012 [RFC6163] the wavelength assignment can be either for a unidirectional lightpath or for a bidirectional lightpath constrained to use the same lambda in both directions. A simple TLV could be used to indication wavelength assignment directionality and wavelength assignment method. This would be placed in an LSP_REQUIRED_ATTRIBUTES object per [RFC5420]. The use of a TLV in the LSP required attributes object was pointed out in [Xu]. [TO DO: The directionality stuff needs to be reconciled with the earlier material] Unique Wavelength: 0 same wavelength in both directions, 1 may use different wavelengths [TBD: shall we use only 1 bit] Wavelength Assignment Method: 0 unspecified (any), 1 First-Fit, 2 Random, 3 Least-Loaded (multi-fiber). Others TBD. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Unique WL | WA Method | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 7. Security Considerations This document has no requirement for a change to the security models within GMPLS and associated protocols. That is the OSPF-TE, RSVP-TE, and PCEP security models could be operated unchanged. However satisfying the requirements for RWA using the existing protocols may significantly affect the loading of those protocols. This makes the operation of the network more vulnerable to denial of service attacks. Therefore additional care maybe required to ensure that the protocols are secure in the WSON environment. Furthermore the additional information distributed in order to address the RWA problem represents a disclosure of network capabilities that an operator may wish to keep private. Consideration should be given to securing this information. Bernstein et al. Expires September 7, 2012 [Page 10] Internet-Draft WSON Signaling Extensions March 2012 8. IANA Considerations TBD. Once finalized in our approach we will need identifiers for such things and modulation types, modulation parameters, wavelength assignment methods, etc... 9. Acknowledgments Anyone who provide comments and helpful inputs Bernstein et al. Expires September 7, 2012 [Page 11] Internet-Draft WSON Signaling Extensions March 2012 10. References 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2578] McCloghrie, K., Perkins, D., and J. Schoenwaelder, "Structure of Management Information Version 2 (SMIv2)", STD 58, RFC 2578, April 1999. [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, December 2001. [RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description", RFC 3471, January 2003. [RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol- Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. [RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links in Resource ReSerVation Protocol - Traffic Engineering (RSVP-TE)", RFC 3477, January 2003. [RFC5420] Farrel, A., Ed., Papadimitriou, D., Vasseur, J.-P., and A. Ayyangar, " Encoding of Attributes for MPLS LSP Establishment Using Resource Reservation Protocol Traffic Engineering (RSVP-TE)", RFC 5420, February 2006. 10.2. Informative References [WSON-CompOSPF] Y. Lee, G. Bernstein, "OSPF Enhancement for Signal and Network Element Compatibility for Wavelength Switched Optical Networks", work in progress: draft-lee-ccamp-wson- signal-compatibility-OSPF. [RFC6163] Y. Lee, G. Bernstein, W. Imajuku, "Framework for GMPLS and PCE Control of Wavelength Switched Optical Networks", work in progress: draft-bernstein-ccamp-wavelength- switched-03.txt, February 2008. Bernstein et al. Expires September 7, 2012 [Page 12] Internet-Draft WSON Signaling Extensions March 2012 [HZang00] H. Zang, J. Jue and B. Mukherjeee, "A review of routing and wavelength assignment approaches for wavelength-routed optical WDM networks", Optical Networks Magazine, January 2000. [Xu] S. Xu, H. Harai, and D. King, "Extensions to GMPLS RSVP-TE for Bidirectional Lightpath the Same Wavelength", work in progress: draft-xu-rsvpte-bidir-wave-01, November 2007. [Winzer06] Peter J. Winzer and Rene-Jean Essiambre, "Advanced Optical Modulation Formats", Proceedings of the IEEE, vol. 94, no. 5, pp. 952-985, May 2006. [G.959.1] ITU-T Recommendation G.959.1, Optical Transport Network Physical Layer Interfaces, March 2006. [G.694.1] ITU-T Recommendation G.694.1, Spectral grids for WDM applications: DWDM frequency grid, June 2002. [G.694.2] ITU-T Recommendation G.694.2, Spectral grids for WDM applications: CWDM wavelength grid, December 2003. [G.Sup43] ITU-T Series G Supplement 43, Transport of IEEE 10G base-R in optical transport networks (OTN), November 2006. [RFC4427] Mannie, E., Ed., and D. Papadimitriou, Ed., "Recovery (Protection and Restoration) Terminology for Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4427, March 2006. [RFC4872] Lang, J., Rekhter, Y., and Papadimitriou, D., "RSVP-TE Extensions in Support of End-to-End Generalized Multi- Protocol Label Switching (GMPLS) Recovery", RFC 4872, [ASSOC-Info] Berger, L., Faucheur, F., and A. Narayanan, "Usage of The RSVP Association Object", draft-ietf-ccamp-assoc-info- 00 (work in progress), October 2010. [ASSOC-Ext] Zhang, F., Jing, R., "RSVP-TE Extension to Establish Associated Bidirectional LSP", draft-zhang-mpls-tp-rsvp- te-ext-associated-lsp-03 (work in progress), February 2011. Bernstein et al. Expires September 7, 2012 [Page 13] Internet-Draft WSON Signaling Extensions March 2012 Author's Addresses Greg M. Bernstein (editor) Grotto Networking Fremont California, USA Phone: (510) 573-2237 Email: gregb@grotto-networking.com Nicola Andriolli Scuola Superiore Sant'Anna, Pisa, Italy Email: nick@sssup.it Alessio Giorgetti Scuola Superiore Sant'Anna, Pisa, Italy Email: a.giorgetti@sssup.it Lin Guo Key Laboratory of Optical Communication and Lightwave Technologies Ministry of Education P.O. Box 128, Beijing University of Posts and Telecommunications, P.R.China Email: guolintom@gmail.com Hiroaki Harai National Institute of Information and Communications Technology 4-2-1 Nukui-Kitamachi, Koganei, Tokyo, 184-8795 Japan Phone: +81 42-327-5418 Email: harai@nict.go.jp Yuefeng Ji Key Laboratory of Optical Communication and Lightwave Technologies Ministry of Education P.O. Box 128, Beijing University of Posts and Telecommunications, P.R.China Email: jyf@bupt.edu.cn Daniel King Old Dog Consulting Email: daniel@olddog.co.uk Young Lee (editor) Huawei Technologies Bernstein et al. Expires September 7, 2012 [Page 14] Internet-Draft WSON Signaling Extensions March 2012 1700 Alma Drive, Suite 100 Plano, TX 75075 USA Phone: (972) 509-5599 (x2240) Email: ylee@huawei.com Sugang Xu National Institute of Information and Communications Technology 4-2-1 Nukui-Kitamachi, Koganei, Tokyo, 184-8795 Japan Phone: +81 42-327-6927 Email: xsg@nict.go.jp Giovanni Martinelli Cisco Via Philips 12 20052 Monza, IT Phone: +39 039-209-2044 Email: giomarti@cisco.com Intellectual Property Statement 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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