CCAMP Working Group Richard Douville Internet Draft Dimitri Papadimitriou Emmanuel Dotaro Expires: April 2003 Alcatel Rauf Izmailov Aleksandar Kolarov NEC October 2002 Extensions to Generalized MPLS in support of Waveband Switching draft-douville-ccamp-gmpls-waveband-extensions-02.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 [1]. 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. 1. Abstract Generalized MPLS (GMPLS) extends the MPLS control plane to encompass time-division, wavelength and spatial switching. A functional description of the extensions to MPLS signaling needed to support the new types of switching is provided in [GMPLS-SIG]. On the other hand, along with the current development on IP over optical switching, there are considerable advances in optical transport systems based on the multiple optical switching granularities. [GMPLS-SIG] currently defines two layers of optical granularity (wavelength and fiber). As described in [IPO-MG], a revisited definition of waveband switching can be introduced. This document presents a functional description of the extensions, to the GMPLS protocol suite, to further integrate optical multi-granularity and benefit from the features of the corresponding switching layers. R.Douville et al. - Internet Draft û Expires April 2003 1 draft-douville-ccamp-gmpls-waveband-extensions-03.txt Oct. 2002 2. Summary for Sub-IP Area 2.1. Summary See the Abstract above. 2.2. Where does it fit in the Picture of the Sub-IP Work This work fits the CCAMP box. 2.3. Why is it Targeted at this WG This draft is targeted at the CCAMP WG, because it specifies the extensions to the GMPLS signaling. GMPLS is itself addressed in the CCAMP WG. 2.4. Justification of Work The WG should consider this document as it specifies the extensions to the GMPLS signaling. These extensions are related to the definition of waveband switching and the introduction of optical multi-granularity. 3. 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 [2]. Other abbreviations and terminology in addition to the [GMPLS-ARCH], [GMPLS-SIG] and [GMPLS-RTG] are: WB LSP = WaveBand LSP WBSC = WaveBand Switching Capable WXC = Wavelength Cross-Connect WBXC = WaveBand Cross-Connect FXC = Fiber Cross-Connect OXC = Optical Cross Connect PXC = Photonic Cross Connect 4. Introduction The optical multi-granularity concept relies on technologies working at the different switching levels (e.g. wavelength, waveband and fiber). In the context of this memo, the granularities considered inside optical networks are single wavelengths (Lambda LSP), bundles of wavelengths referred to as wavebands (WB LSP), and whole fibers (Fiber LSP). One of the key benefits of multi-granularity is to simplify the switching procedures of multiple lower order LSPs (Lambda LSPs, for instance) by switching these LSPs as a single entity or LSP at a higher order (e.g. WB LSP or Fiber LSP). To R.Douville et al. - Internet Draft û Expires April 2003 2 draft-douville-ccamp-gmpls-waveband-extensions-03.txt Oct. 2002 enable such grouping of LSPs, several grooming strategies can be employed (either end-to-end or intermediate). This memo proposes to extend GMPLS previous set of switching capabilities in the optical domain, by identifying uncovered characteristics of the optical transport, taking into account interest for optical components working at the band level and its impact on the control of the optical networks. In the efforts of describing the requirements and set of capabilities for optical multi-granularity, three approaches to waveband switching have been identified: - Inverse Multiplexing - Wavelength Concatenation - Waveband The common availability of optical/photonic switching equipment capable to work at the band level motivates the redefinition of waveband switching as defined in the GMPLS architecture. Current definition of waveband switching (see [GMPLS-ARCH] and [GMPLS-SIG]) refers to inverse multiplexing mechanism or wavelength concatenation (ôcontiguousö lambdas in a trunk defining a logical waveband at the control plane level). While this definition is still valid and applicable, it does not consider the approach where wavebands have a physical significance, i.e. where the interface is WaveBand-Switch Capable (WBSC). Physical waveband has the ability to switch directly a portion of the frequency spectrum without the need to distinguish between its inner components (e.g. wavelengths or even below in certain known cases). The following document groups the extensions to the GMPLS protocol suite required to provide optical multi-granularity (distributed) control and particularly the extensions required for waveband switching support. 5. Extensions to the GMPLS Architecture and Protocol Suite 5.1. Architecture The integration of optical multi-granularity in the GMPLS architecture requires some extensions to the definitions it currently includes. The [GMPLS-ARCH] document considers waveband switching a particular case of lambda switching. As specified, a waveband represents a set of contiguous wavelengths, which can be switched together. This definition of waveband is too restrictive at least on two key aspects: - The first one is that current definition of waveband implies a wavelength composition of the waveband, due to waveband switching by wavelength cross-connects (WXC). This definition provides support to inverse multiplexing mechanism and wavelength concatenation. This approach limits the use of waveband to the wavelength switch capable technologies. With waveband switching technologies, the interface R.Douville et al. - Internet Draft û Expires April 2003 3 draft-douville-ccamp-gmpls-waveband-extensions-03.txt Oct. 2002 does not distinguish between the component optical channels, sub- channels (i.e. timeslots) or packets on the waveband which is switch as a single unit (wide frequency spectrum) like it could be done with the fibers (the penultimate frequency spectrum) on photonic cross-connect (PXC). - The second restrictive point is that the current definition of the waveband does not enable intermediate grooming strategies. For this purpose, this memo introduces an additional optical granularity representing the waveband. This definition is quite general and backward compatible, it allows requesting a set of contiguous wavelengths (i.e. inverse multiplexing mechanism and wavelength concatenation) but also address the "real" waveband switching and the corresponding set of capabilities. Therefore, the proposed definition better fits into the whole GMPLS architecture. Correspondingly, this memo specifies a new type of interface switching capable interface: the Waveband-Switch Capable Interface (WBSC). The WBSC interface materializes the physical reality of optical waveband in the form of an atomic entity or granularity. As with the introduction of the waveband switching capable interface, a new class of LSP is defined: the WaveBand LSP (WB LSP). The below figure illustrates the hierarchy of the (optical) switching layers and highlights the optical multi-granularity part. The switching element column shows typical (piece of) equipment that can be part of the same node and thus simultaneously support such interfaces. LSP Hierarchy Interfaces Switching Element ------------- ---------- ----------------- Lambda LSP (1) <---> LSC <----> WXC - | WB LSP (1) <---> WBSC <----> WBXC > Optical MG | Fiber LSP <---> FSC <----> FXC - (1) WB LSPs can be supported on both Lambda and WaveBand Switch Capable interfaces depending on the nature of the waveband being requested (inverse multiplexing, wavelength concatenation, and physical waveband). Note that this representation does not aim at restricting interfaces that network elements can support. 5.2 GMPLS Signalling 5.2.1 Generalized Label Request To support Waveband LSP request, the values of the LSP Encoding Type, the Switching Type and the Generalized PID (G-PID) fields included in the Generalized Label Request, are extended. R.Douville et al. - Internet Draft û Expires April 2003 4 draft-douville-ccamp-gmpls-waveband-extensions-03.txt Oct. 2002 The information carried in a Generalized Label Request is: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LSP Enc. Type |Switching Type | G-PID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ LSP Encoding Type: 8 bits Indicates the encoding of the LSP being requested. The following Value 14 and Type Waveband (Photonic) is added to the existing LSP Encoding Type values to provide Waveband LSP support: Value Type ----- ---- 1 Packet 2 Ethernet 3 ANSI/ETSI PDH 4 Reserved 5 SDH ITU-T G.707 / SONET ANSI T1.105 6 Reserved 7 Digital Wrapper 8 Lambda (photonic) 9 Fiber 10 Reserved 11 FiberChannel 12 G.709 ODUk (Digital Path) 13 G.709 Optical Channel 14 Waveband (Photonic) For example, consider an LSP signaled with "WaveBand" encoding. It is expected that such an LSP would be supported with no electrical conversion and no knowledge of the frequency cutting, modulation and speed by the transit nodes. Other formats normally require framing knowledge, and field parameters are broken into the framing type and speed. Switching Type: 8 bits Indicates the type of switching that should be performed on a particular link. This field is needed for links that advertise more than one type of switching capability. For OXC or PXC enabling Waveband switching, the WBSC value is used to refer to such switching capability. Other values of this field are as the Switching Capability field defined in [GMPLS-RTG] Generalized PID (G-PID): 16 bits An identifier of the payload carried by an LSP, i.e. an identifier of the client layer of that LSP. This is used by R.Douville et al. - Internet Draft û Expires April 2003 5 draft-douville-ccamp-gmpls-waveband-extensions-03.txt Oct. 2002 the nodes at the endpoints of the LSP, and in some cases by the penultimate hop. Standard Ethertype values are used for packet and Ethernet LSPs; other values are defined in [GMPLS-SIG]. A waveband can carry a Lambda LSP while a Waveband LSP can be transported on a Fiber LSP, the following additional G-PID values must be considered: see [GMPLS-SIG] section 3.1.1 û Required Information, paragraph on Generalized-PID Value Type Technology ----- ---- ---------- 37 Lambda Waveband, Fiber .. ... ... 58 Waveband Fiber In addition the following existing values must be updated in order to reflect the transport of Ethernet and SDH/SONET payload over a waveband LSP: 33 Ethernet SDH, Lambda, Fiber 34 SDH Lambda, Waveband, Fiber 35 Reserved None 36 Digital Wrapper Lambda, Waveband, Fiber 5.2.2 Generalized Label As currently proposed in [GMPLS-SIG], the waveband label space definition is perfectly suitable for waveband switching as proposed in this memo and does not require any modification or extension. 5.3. GMPLS Routing 5.3.1 Waveband Interface Switching Capability A new WaveBand-Switch Capability (WBSC) value shall be defined to identify and distinguish the associated switching capability of a link [MPLS-HIER]. If the switching capability of a (TE) link is of type WBSC, it means that the node receiving data over this link (fiber) can recognize and switch individual WaveBands on this link (without distinguishing lambdas, channels or packets). Values defined in [GMPLS-RTG] and the one defined in the present context gives the following Interface Switching Capabilities list: Packet-Switch Capable-1 (PSC-1) Packet-Switch Capable-2 (PSC-2) Packet-Switch Capable-3 (PSC-3) Packet-Switch Capable-4 (PSC-4) Layer-2 Switch Capable (L2SC) Time-Division-Multiplex Capable (TDM) Lambda-Switch Capable (LSC) Waveband-Switch Capable (WBSC) Fiber-Switch Capable (FSC) R.Douville et al. - Internet Draft û Expires April 2003 6 draft-douville-ccamp-gmpls-waveband-extensions-03.txt Oct. 2002 Note that the node that is advertising a given link (i.e., the node that is transmitting) has to know the switching capabilities at the other end of the link (i.e., the receiving end of the link). One way to accomplish this is through configuration. Other options to accomplish this are outside the scope of this document. In brief, if an interface is of type WBSC, it means that the node receiving data over this interface can recognize and switch wavebands (sets of contiguous lambdas) within the interface as a unit (without distinguishing lambdas, sub-channels or packets). On the other hand, an interface that allows for waveband switching belongs (at least) to the WBSC type. 5.3.2. Interface Switching Capability Descriptor For ISIS, the Interface Switching Capability Descriptor is a sub-TLV (of type 21) of the extended IS reachability TLV. The length is the length of value field in octets. For OSPF, the Interface Switching Capability Descriptor is a sub-TLV of the Link TLV with type 15. The length is the length of value field in octets. The common format of the Interface Switching Capability Descriptor is defined in [GMPLS-OSPF] and [GMPLS-ISIS], respectively. A new value for the Switching Capability (Switching Cap) field is defined here to identify Waveband-Switch Capable (WBSC) interfaces: 151 Waveband Switching Capable (WBSC) In the Interface Switching Capability Descriptor (ISCD), when the Switching Capability (Switching Cap) field contains the value for WBSC, the technology specific information field includes the Minimum LSP Bandwidth, which is defined as the number of contiguous wavelength constituting a WaveBand entity. Additional technology specific information may also be considered such as the channel spacing. 5.4. LSP Regions and Forwarding Adjacencies The information carried in the Switching Capability field (8 bits) of the Interface Switching Capability Descriptor (ISCD) is used to construct LSP regions, and determine regionsÆ boundaries as defined in [MPLS-HIER]. The introduction of the new WBSC Interface Switching Capability define a new ordering among the switching capabilities: PSC-1 < PSC- 2 < PSC-3 < PSC-4 < TDM < LSC < WBSC < FSC. Path computation may take into account this region boundary when computing a path for an LSP. When an LSP need to cross a region R.Douville et al. - Internet Draft û Expires April 2003 7 draft-douville-ccamp-gmpls-waveband-extensions-03.txt Oct. 2002 boundary, it can trigger the establishment of a Forwarding Adjacency LSP (FA-LSP) at the underlying layer. The new cascading of FAs can be triggered between layers with the new following obvious order: L2SC, then TDM, then LSC, then WBSC and then finally FSC. 6. Security Considerations No additional security considerations beyond the one covered in RSVP-TE (see [RFC-3209]) and CR-LDP (see [RFC-3212]). 7. References 7.1 Normative References [GMPLS-LDP] L.Berger (Editor) et al., æGeneralized MPLS Signaling - CR-LDP ExtensionsÆ, Internet Draft, Work in progress, draft-ietf-mpls-generalized-cr-ldp-07.txt, August 2002. [GMPLS-ISIS] K.Kompella et al., æIS-IS Extensions in Support of Generalized MPLSÆ, Internet Draft, Work in progress, draft-ietf-isis-gmpls-extensions-14.txt, August 2002. [GMPLS-OSPF] K.Kompella et al., æOSPF Extensions in Support of Generalized MPLSÆ, Internet Draft, Work in progress, draft-ietf-ccamp-ospf-gmpls-extensions-08.txt, August 02. [GMPLS-RSVP] L.Berger (Editor) et al., æGeneralized MPLS Signaling - RSVP-TE ExtensionsÆ, Internet Draft, Work in progress, draft-ietf-mpls-generalized-rsvp-te-09.txt, October 2002. [GMPLS-RTG] K.Kompella et al., æRouting Extensions in Support of Generalized MPLSÆ, Internet Draft, Work in Progress, draft-ietf-ccamp-gmpls-routing-05.txt, August 2002. [GMPLS-SIG] L.Berger (Editor) et al., æGeneralized MPLS - Signaling Functional DescriptionÆ, Internet Draft, Work in progress, draft-ietf-mpls-generalized- signaling-09.txt, August 2002. [ISIS-TE] T.Li et al., æIS-IS Extensions for Traffic EngineeringÆ, Internet Draft, Work in progress, draft- ietf-isis-traffic-04.txt, November 2001. [MPLS-BUNDLE]K.Kompella et al., æLink Bundling in MPLS Traffic EngineeringÆ, Internet Draft, draft-ietf-mpls-bundle- 04.txt, August 2002. [MPLS-HIER] K.Kompella et al., æLSP Hierarchy with MPLS TEÆ, Internet Draft, Work in progress, draft-ietf-mpls-lsp- hierarchy-08.txt, August 2002. R.Douville et al. - Internet Draft û Expires April 2003 8 draft-douville-ccamp-gmpls-waveband-extensions-03.txt Oct. 2002 [OSPF-TE] D.Katz et al., æTraffic Engineering Extensions to OSPFÆ, Internet Draft, Work in progress, draft-katz- yeung-ospf-traffic-08.txt, October 2002. [RFC-3209] D.Awduche (Editor) et al., æRSVP-TE: Extensions to RSVP for LSP TunnelsÆ, Internet RFC 3209, IETF Proposed Standard, December 2001. [RFC-3212] B.Jamoussi (Editor) et al. æConstraint-Based LSP Setup using LDPÆ, Internet RFC 3212, IETF Proposed Standard, January 2002. 7.2 Informative References [GMPLS-ARCH] E.Mannie (Editor) et al., æGeneralized Multi-Protocol Label Switching (GMPLS) ArchitectureÆ, Internet Draft, Work in progress, draft-ietf-ccamp-gmpls-architecture- 03.txt, August 2002. [RFC-2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels," RFC 2119. 8. Author's Addresses Richard Douville (Alcatel) Route de Nozay, 91460 Marcoussis, France Phone: +33 1 6963-4431 Email: richard.douville@alcatel.fr Martin Vigoureux (Alcatel) Route de Nozay, 91460 Marcoussis, France Phone: +33 1 6963-1852 Email: martin.vigoureux@alcatel.fr Emmanuel Dotaro (Alcatel) Route de Nozay, 91460 Marcoussis, France Phone: +33 1 6963-4723 Email: emmanuel.dotaro@alcatel.fr Dimitri Papadimitriou (Alcatel) Francis Wellesplein 1, B-2018 Antwerpen, Belgium Phone: +32 3 240-8491 Email: dimitri.papadimitriou@alcatel.be Rauf Izmailov (NEC Laboratories America, Inc.) 4 Independence Way, Princeton, NJ 08540, USA Phone: +1 609 951-2454 Email: rauf@nec-lab.com Aleksandar Kolarov (NEC Laboratories America, Inc.) 4 Independence Way, R.Douville et al. - Internet Draft û Expires April 2003 9 draft-douville-ccamp-gmpls-waveband-extensions-03.txt Oct. 2002 Princeton, NJ 08540, USA Phone: +1-609-951-2985 Email: kolarov@nec-lab.com R.Douville et al. - Internet Draft û Expires April 2003 10 draft-douville-ccamp-gmpls-waveband-extensions-03.txt Oct. 2002 9. Full Copyright Statement "Copyright (C) The Internet Society (date). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE." R.Douville et al. - Internet Draft û Expires April 2003 11