INTERNET DRAFT Tomohiro Otani Updates: RFC 3471 KDDI R&D Labs Intended status: standard track (Editor) Expires: Nov. 27, 2008 May 27, 2008 Generalized Labels for G.694 Lambda-Switching Capable Label Switching Routers Document: draft-ietf-ccamp-gmpls-g-694-lambda-labels-01.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 has defined that a wavelength label (section 3.2.1.1) "only has significance between two neighbors" and global wavelength continuity is not considered. In order to achieve interoperability in a network composed of next generation lambda switch-capable equipment, this document defines a standard lambda label format, being compliant with ITU-T G.694. Moreover some consideration on how to ensure lambda continuity with RSVP-TE is provided. 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 T. Otani et al. Standard track - Expires Aug. 2008 [Page 1]
Internet Drafts May 2008 Status of this Memo................................................ 1 Abstract........................................................... 1 1. Introduction.................................................... 3 2. Conventions used in this document............................... 3 3. Assumed network model and related problem statement............. 3 4. Label Related Formats........................................... 5 5. Security consideration.......................................... 8 6. Acknowledgement................................................. 8 7. References...................................................... 8 7.1. Normative References.......................................... 8 7.2. Informative References........................................ 8 Editor's address................................................... 9 Contributors' address.............................................. 9 Intellectual property considerations............................... 9 Copyright statement............................................... 10 T. Otani et al. Standard track - Expires Nov. 2008 [Page 2]
Internet Drafts May 2008 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: o Layer-2 Switch Capable (L2SC) o Time-Division Multiplex (TDM) o Lambda Switch Capable (LSC) o 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 and the wavelength defined in [G.694] is widely utilized. 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' networks are 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 not only within Domain A but also over multiple domains satisfying wavelength constraints. Figure 2 illustrates in detail the interconnection between Domain A and Domain B. T. Otani et al. Standard track - Expires Nov. 2008 [Page 3]
Internet Drafts May 2008 | 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) | | | |D|-| PXC +-+D| |D+-+ PXC | +--------+ +--------+ +=|==+W|-| +-+W+=====+W+-+ | Node-4 Node-5 | |D|-| (LSC) +-+D| |D+-+ (LSC) | | |M|-| +-+M| |M+-+ | | +-+ +-------+ +-+ +-+ +-------+ | Node-8 Node-9 Figure 1 Wavelength-based network model. +-------------------------------------------------------------+ | Domain A | Domain B | | | | | +---+ lambda 1 | +---+ | | | |---------------|---------| | | | WDM | N | lambda 2 | | N | WDM | | =====| O |---------------|---------| O |===== | | O | D | . | | D | O | | T WDM | E | . | | E | WDM T | | H =====| 2 | lambda n | | 7 |===== H | | E | |---------------|---------| | E | | R +---+ | +---+ R | | | | | N +---+ | +---+ N | | O | | | | | O | | D WDM | N | | | N | WDM D | | E =====| O | WDM | | O |===== E | | S | D |=========================| D | S | | WDM | E | | | E | WDM | | =====| 5 | | | 8 |===== | | | | | | | | | +---+ | +---+ | +-------------------------------------------------------------+ T. Otani et al. Standard track - Expires Nov. 2008 [Page 4]
Internet Drafts May 2008 Figure 2 Interconnecting details between two domains. In the scenario of Figure 2, consider the setting up of a bidirectional LSP from ingress switch 1 to egress switch 4. In order to satisfy wavelength continuity constraint, a fixed wavelength (lambda 1) needs to be used in domain A and domain B. A Path message will be used for the signaling, the PATH message must contain the upstream label and a label set object; both containing the same lambda. The label set object is made by only one sub channel that must be 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. Therefore, 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. As identical wavelength information, 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) are used by LSRs and should be followed as a wavelength label. 4. Label Related Formats 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 based on [G.694] and Label Set definition specific for LSC LSRs. 4.1 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]. In that sense, we can call G.694 wavelength labels. T. Otani et al. Standard track - Expires Nov. 2008 [Page 5]
Internet Drafts May 2008 Since the ITU-T DWDM grid is based on nominal central frequencies, we need to 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) = 193.1 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 or 0.1 THz. When wider channel spacing such as 0.2 THz is utilized, the combination of narrower channel spacing and the value n can provide proper frequency with that channel spacing. Channel spacing is not utilized to indicate the LSR capability but only to specify a frequency in signaling. 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 wavelength is calculated as follows Wavelength (nm) = 1470 nm + n * 20 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. 4.2 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| Reserved | n | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (1) Grid: 3 bits 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 | +----------+---------+ T. Otani et al. Standard track - Expires Nov. 2008 [Page 6]
Internet Drafts May 2008 |Future use| 3 - 7 | +----------+---------+ (2) C.S.(channel spacing): 4 bits DWDM channel spacing is defined as follows. +----------+---------+ | C.S(GHz) | Value | +----------+---------+ | 12.5 | 1 | +----------+---------+ | 25 | 2 | +----------+---------+ | 50 | 3 | +----------+---------+ | 100 | 4 | +----------+---------+ |Future use| 5 - 15 | +----------+---------+ (3) S: 1 bit Sign for the value of n, set to 1 for (-) and 0 for (+) (4) n: 16 bits The value used to compute the frequency as shown above. 4.3 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 | Reserved | n | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (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 | +----------+---------+ T. Otani et al. Standard track - Expires Nov. 2008 [Page 7]
Internet Drafts May 2008 (2) Lambda: 8 bits The value used to compute the wavelength as shown above. 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. 5. 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. 6. Acknowledgement The authors would like to thank Adrian Farrel, Lawrence Mao and Zafar Ali for the discussion. 7. References 7.1. 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. 7.2. Informative References [GMPLS-CSPF] Otani, T., et al, "Considering Generalized Multiprotocol Label Switching Traffic Engineering Attributes During Path Computation", draft-otani-ccamp-gmpls-cspf-constraints-07.txt, Nov. 2007. [G.694.1] ITU-T Recommendation G.694.1, "Spectral grids for WDM applications: DWDM frequency grid", June 2002. T. Otani et al. Standard track - Expires Nov. 2008 [Page 8]
Internet Drafts May 2008 [G.694.2] ITU-T Recommendation G.694.2, "Spectral grids for WDM applications: CWDM wavelength grid", December 2003. Editor's address Tomohiro Otani KDDI R&D Laboratories, Inc. 2-1-15 Ohara Kamifukuoka Saitama, 356-8502, Japan Phone: +81-49-278-7357 Email: otani@kddilabs.jp Contributors' address Richard Rabbat Google, Inc. 1600 Amphitheatre Pkwy Mountain View, CA 94043 Email: rabbat@alum.mit.edu Sidney Shiba Email: sidney.shiba@yahoo.com Hongxiang Guo KDDI R&D Laboratories, Inc. 2-1-15 Ohara Fujimino Saitama, 356-8502, Japan. Phone: +81-49-278-7864. Email: ho-guo@kddilabs.jp Keiji Miyazaki Fujitsu Laboratories Ltd 4-1-1 Kotanaka Nakahara-ku, Kawasaki Kanagawa, 211-8588, Japan Phone: +81-44-754-2765 Email: miyazaki.keiji@jp.fujitsu.com Diego Caviglia Ericsson 16153 Genova Cornigliano, ITALY Phone: +390106003736 Email: diego.caviglia@ericsson.com 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. T. Otani et al. Standard track - Expires Nov. 2008 [Page 9]
Internet Drafts May 2008 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. Copyright statement Copyright (C) The IETF Trust (2008). 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. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM 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. T. Otani et al. Standard track - Expires Nov. 2008 [Page 10]
