IETF Internet Draft T. Otani Updates: RFC 3471 H. Guo Proposed status: standard track KDDI R&D Labs Expires:Dec. 2007 K. Miyazaki Fujitsu Lab. Diego Caviglia Ericsson June 2007 Generalized Labels of Lambda-Switching Capable Label Switching Routers (LSR) Document: draft-otani-ccamp-gmpls-lambda-labels-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of 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. Abstract Technology in the optical domain is constantly evolving and as a consequence new equipment providing lambda switching capability has been developed and is currently being deployed. However, RFC 3471 [RFC3471] has defined that a wavelength label (section 3.2.1.1) "only has significance between two neighbors" and global wavelength continuity is not considered and getting significant. In order to achieve interoperability in a network composed of new generation lambda switch-capable equipment, this document proposes a standard lambda label format. Moreover some consideration on how to ensure lambda continuity with RSVP-TE is provided. T. Otani et al. Standard track - Expires Dec. 2007 1 Internet Drafts June 2007 This document is a companion to the Generalized Multi-Protocol Label Switching (GMPLS) signaling. It defines the label format when Lambda Switching is requested in an all optical network. Table of Contents Status of this Memo................................................1 Abstract...........................................................1 1. Introduction....................................................3 2. Conventions used in this document...............................3 4. Requirements on Label Identification............................5 7. Security consideration..........................................9 8. Acknowledgement................................................10 9. Intellectual property considerations...........................10 Author's Addresses................................................11 Document expiration...............................................11 Copyright statement...............................................11 T. Otani et al. Informational - Expires Dec. 2007 2 Internet Drafts June 2007 1. Introduction As described in [RFC3945], Generalized MPLS (GMPLS) extends MPLS from supporting only packet (Packet Switching Capable - PSC) interfaces and switching to also include support for four new classes of interfaces and switching: - Layer-2 Switch Capable (L2SC) - Time-Division Multiplex (TDM) - Lambda Switch Capable (LSC) - Fiber-Switch Capable (FSC). A functional description of the extensions to MPLS signaling needed to support new classes of interfaces and switching is provided in [RFC3471]. This document presents details that are specific to the use of GMPLS with a new generation of Lambda Switch Capable (LSC) equipment. Technologies such as Reconfigurable Optical Add/Drop Multiplex (ROADM) and Wavelength Cross-Connect (WXC) operate at the wavelength switching level. As such, the wavelength is important information that is necessary to set up a wavelength-based LSP appropriately. 2. 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. Assumed network model and related problem statement Figure 1 depicts an all-optically switched network consisting of different vendor's optical network domains. Vendor A's network is a ring topology that consists of ROADM or WXC, and vendor B's network is a mesh topology consisting of PXCs and DWDMs, otherwise both vendors’ network is based on the same technology. In this case, the use of standardized wavelength label information is quite significant to establish a wavelength-based LSP. It is also an important constraint when conducting CSPF calculation for RSVP-TE signaling. The way the CSPF is performed is outside the scope of this document, but defined in [GMPLS-CSPF]. It is needless to say, a LSP must be appropriately provisioned between a selected pair of ports within Domain A, considering wavelength information. Even over multiple domains, a LSP must be accordingly established satisfying wavelength constraints. Figure 2 illustrates in detail the interconnection between Domain A and Domain B. T. Otani et al. Informational - Expires Dec. 2007 3 Internet Drafts June 2007 | Domain A (or Vendor A) | Domain B (or Vendor B) | Node-1 Node-2 | Node-6 Node-7 +--------+ +--------+ | +-------+ +-+ +-+ +-------+ | ROADM | | ROADM +---|---+ PXC +-+D| |D+-+ PXC | | or WXC +========+ or WXC +---|---+ +-+W+=====+W+-+ | | (LSC) | | (LSC) +---|---+ (LSC) +-+D| |D+-+ (LSC) | +---+----+ +--------+ | | +-|M| |M+-+ | || || | +++++++++ +-+ +-+ +++++++++ || Node-3 || | ||||||| ||||||| || +--------+ || | +++++++++ +++++++++ ||===| WXC +===|| | | DWDM | | DWDM | | (LSC) | | +--++---+ +--++---+ ||===+ +===|| | || || || +--------+ || | +--++---+ +--++---+ || || | | DWDM | | DWDM | +--------+ +--------+ | +++++++++ +++++++++ | ROADM | | ROADM | | ||||||| ||||||| | or WXC +========+ or WXC | | +++++++++ +-+ +-+ +++++++++ | (LSC) | | (LSC) | | | PXC +-+D| |D+-+ PXC | +--------+ +--------+ | | +-+W+=====+W+-+ | Node-4 Node-5 | | (LSC) +-+D| |D+-+ (LSC) | | | +-+M| |M+-+ | | +-------+ +-+ +-+ +-------+ | Node-8 Node-9 Figure 1 Wavelength-based network model +---------------------------------------------------------------+ | Domain A | Domain B | | | | | +---+ +---+ lambda 1 | +---+ +---+ | | | | |L S|---------------|---------|L S| |L S|-- | | --| | |A W| lambda 2 | |A W| |A W|-- | | --| | WDM |M I|---------------|---------|M I| |M I|-- | | --|L S|=====|B T| . | |B T| WDM |B T|-- | | --|A W| |D C| . | |D C|=====|D C|-- | | --|M I| |A H| lambda n | |A H| |A H|-- | | --|B T| | 2|---------------|---------| 3| | 4|-- | | --|D C| +---+ | +---+ +---+ | | --|A H| | | | --| 1| +---+ | +---+ +---+ | | --| | |L S| | |L S| |L S|-- | | --| | |A W| | |A W| |A W|-- | | --| | WDM |M I| WDM | |M I| WDM |M I|-- | | --| |=====|B T|=========================|B T|=====|B T|-- | | --| | |D C| | |D C| |D C|-- | | --| | |A H| | |A H| |A H|-- | | | | | 5| | | 6| | 7|-- | | +---+ +---+ | +---+ +---+ | +---------------------------------------------------------------+ Figure 2 Interconnecting details between two domains T. Otani et al. Informational - Expires Dec. 2007 4 Internet Drafts June 2007 In the scenario of Figure 2, consider the setting up of a bidirectional LSP from ingress switch 1 to egress switch 4. A fixed wavelength (lambda 1) will be used in domain A throughout domain B satisfying wavelength continuity. A Path message will be used for the signaling, the PATH message must contain the upstream label and a label set object; both this two objects have to contain the same lambda, that is, the label set object is made by only one sub channel that must be the same as the upstream label. The path setup will continue downstream to switch 4 by configuring each lambda switch based on the wavelength label. This label allows the correct switching of lambda switches and the label contents needs to be used over the inter-domain. As same above, the path setup will continue downstream to switch 7 by configuring lambda switch based on multiple wavelength labels. If the node has a tunable wavelength transponder, the tuning wavelength is considered as a part of wavelength switching operation. Not using a standardized label would add undue burden on the operator to enforce policy as each manufacturer may decide on a different representation and therefore each domain may have its own label formats. Moreover, manual provisioning may lead to misconfiguration if domain-specific labels are used. 4. Requirements on Label Identification Here, some signaling-related requirements are listed considering actual operation of above wavelength switched optical networks. 1. A wavelength label SHOULD be standardized in order to allow interoperability between multiple domains; otherwise appropriate existing labels are identified in support of wavelength availability. 2. The ITU-T frequency grid specified in [G.694.1] for Dense WDM (DWDM) and wavelength information in [G.694.2] for Coarse WDM (CWDM) SHOULD be used by LSC LSRs when setting up LSPs. 3. Labels SHOULD be stable and not allow for rounding errors. 4. Existing labels should be still utilized appropriately even if wavelength availability is advertised. Moreover, some routing-related requirements are indicated, but not covered in this document. 5. An operator MAY want to advertise wavelength availability in the network. 6. Care SHOULD be taken if advertising the wavelength availability in order to reduce impact on the existing OSPF-TE. 7. To decrease the probability of operators' error or difficulties, it is RECOMMENDED that advertising using OSPF-TE/ISIS-TE be standardized to simplify management. 5. Label Related Formats T. Otani et al. Informational - Expires Dec. 2007 5 Internet Drafts June 2007 To deal with the widening scope of MPLS into the optical and time domains, several new forms of "label" have been defined in [RFC3471]. This section contains clarifications for the Wavelength label and Label Set definition specific for LSC LSRs. 5.1 Wavelength Labels In section 3.2.1.1 of [RFC3471], a Wavelength label is defined to have significance between two neighbors, and the receiver may need to convert the received value into a value that has local significance. LSC equipment uses multiple wavelengths controlled by a single control channel. In such case, the label indicates the wavelength to be used for the LSP. This document proposes to standardize the wavelength label. As an example of wavelength values, the reader is referred to [G.694.1] which lists the frequencies from the ITU-T DWDM frequency grid. The same can be done for CWDM technology by using the wavelength defined in [G.694.2]. Since the ITU-T DWDM grid is based on nominal central frequencies, we will indicate the appropriate table, the channel spacing in the grid and a value n that allows the calculation of the frequency. That value can be positive or negative. The frequency is calculated as such in [G.694.1]: Frequency (THz) = 193.0 THz + n * channel spacing (THz) , Where n is an integer (positive, negative or 0) and channel spacing is defined to be 0.0125, 0.025, 0.05, 0.1, or 0.2 THz. For the other example of the case of the ITU-T CWDM grid, the spacing between different channels was defined to be 20nm, so we need to pass the wavelength value in nm in this case. Examples of CWDM wavelengths are 1470, 1490, etc. nm. The tables listed in [G.694.1] and [G.694.2] are not numbered and change with the changing frequency spacing as technology advances, so an index is not appropriate in this case. 5.2 DWDM Wavelength Label For the case of DWDM, the information carried in a Wavelength label 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Grid | C.S.|S| n | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (1) Grid: 3 bits T. Otani et al. Informational - Expires Dec. 2007 6 Internet Drafts June 2007 The value for grid is set to 1 for ITU-T DWDM Grid as defined in [G.694.1]. +----------+---------+ | Grid | Value | +----------+---------+ |ITU-T DWDM| 1 | +----------+---------+ |ITU-T CWDM| 2 | +----------+---------+ |Future use| 3 - 7 | +----------+---------+ (2) C.S.(channel spacing): 3 bits DWDM channel spacing is defined as follows. +----------+---------+ | C.S(GHz) | Value | +----------+---------+ | 12.5 | 1 | +----------+---------+ | 25 | 2 | +----------+---------+ | 50 | 3 | +----------+---------+ | 100 | 4 | +----------+---------+ | 200 | 5 | +----------+---------+ |Future use| 6 – 7 | +----------+---------+ (3) S: 1 bit Sign for the value of n, set to 1 for (-) and 0 for (+) (4) n: 9 bits The value used to compute the frequency as shown above. 5.3 CWDM Wavelength Label For the case of CWDM, the information carried in a Wavelength label 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Grid | Lambda | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ T. Otani et al. Informational - Expires Dec. 2007 7 Internet Drafts June 2007 (1) Grid: 3 bits The value for grid is set to 2 for ITU-T CWDM Grid as defined in [G.694.2]. +----------+---------+ | Grid | Value | +----------+---------+ |ITU-T DWDM| 1 | +----------+---------+ |ITU-T CWDM| 2 | +----------+---------+ |Future use| 3 - 7 | +----------+---------+ (2) Lambda: 11 bits Integer value of lambda in nm is defined as below. +-------------+ | Lambda (nm) | +-------------+ | 1470 | +-------------+ | 1490 | +-------------+ | 1510 | +-------------+ | 1530 | +-------------+ | 1550 | +-------------+ | 1590 | +-------------+ | 1610 | +-------------+ We do not need to define a new type as the information stored is either a port label or a wavelength label. Only the wavelength label as above needs to be defined. 6. Lambda constraint in all-optical networks 6.1 Wavelength continuity An all-optical network imposes the Lambda continuity constraint, that is, a label cannot be changed hop by hop, but must have an end to end scope. The above is not supported by RFC3471 that states that a label has significance only between two neighbors. T. Otani et al. Informational - Expires Dec. 2007 8 Internet Drafts June 2007 This memo changes the way an all optical node process and manage a Path message with Lambda label. Two possible scenarios are taken into consideration: 1. The node is able via OEO operation to change the Lambda 2. The node is a pure optical device and is not able to change the Lambda The first scenario can be supported either by nodes with a double switching matrix (eclectic and optic) but also by nodes that have only an optic matrix and a G.709 tunable transponder on the outgoing interface. This scenario is covered by 3471 procedures and then will not be taken into consideration in the following. Scenario 2 imposes in case of bidirectional LSPs some constraints: . on the same hop Upstream and Downstream must be the same; . on an end to end basis the LSP must use the same Label The first constraint do not need any modification to the already defined RSVP-TE protocols and behaviors, and can be satisfied just setting the Upstream Label value equal to the Label Set subchannel value. The action must be inclusive and there must be only one subchannel in the object. The second constraint cannot be satisfied with the way RSVP-TE works today. The solution proposed here is: if a node is not able to perform OEO conversion then it must use on its outgoing interface the same Lambda it received on the incoming interface. The above applies in the case the ERO does not contain information up to the label level. 6.2 Advertising wavelength availability Wavelength availability may be thought of as a constraint in an all- optical network. Although it may be collected through an EMS/NMS system, operators may want to have it advertised using GMPLS routing. It may be needed to standardize the information advertised using OSPF-TE and ISIS-TE if an operator wishes to have it advertised. This allows the operator to parse LSA information without regard to the applied policy in different manufacturer domains. However, more investigation to extend the existing routing protocol is required from the point of routing scalability and this consideration is out of scope in this document. 7. Security consideration This document introduces no new security considerations to [RFC3473]. GMPLS security is described in section 11 of [RFC3471] and refers to [RFC3209] for RSVP-TE. T. Otani et al. Informational - Expires Dec. 2007 9 Internet Drafts June 2007 8. Acknowledgement The authors would like to express their thanks to Sidney Shiba, Richard Rabbat for originally initiating this work. They also thank Adrian Farrel and Lawrence Mao for the discussion. 9. Intellectual property considerations The IETF 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 this 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. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf- ipr@ietf.org. 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. [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 (MPLS) Signaling Functional Description", RFC 3471, January 2003. [RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching (MPLS} Signaling - Resource ReserVation Protocol Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. [RFC3945] Mannie, E., Ed., "Generalized Multiprotocol Label Switching (GMPLS) Architecture", RFC 3945, October 2004. T. Otani et al. Informational - Expires Dec. 2007 10 Internet Drafts June 2007 10.2. Informative References [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. [GMPLS-CSPF] Otani, T., et al, "Considering Generalized Multiprotocol Label Switching Traffic Engineering Attributes During Path Computation", draft-otani-ccamp-gmpls-cspf-constraints-05.txt, March 2007. Author's Addresses Tomohiro Otani KDDI R&D Laboratories, Inc. 2-1-15 Ohara Fujimino Phone: +81-49-278-7357 Saitama, 356-8502. Japan Email: otani@kddilabs.jp Hongxiang Guo KDDI R&D Laboratories, Inc. 2-1-15 Ohara Fujimino Phone: +81-49-278-7864 Saitama, 356-8502. Japan Email: ho-guo@kddilabs.jp Keiji Miyazaki Fujitsu Laboratories Ltd 4-1-1 Kotanaka Nakahara-ku, Kawasaki Phone: +81-44-754-2765 Kanagawa, 211-8588. Japan Email: miyazaki.keiji@jp.fujitsu.com Diego Caviglia Ericsson 16153 Genova Cornigliano Phone: +390106003736 ITALY Email: diego.caviglia@ericsson.com Document expiration This document will be expired in Dec. 30, 2007, unless it is updated. Copyright statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. 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