--- 1/draft-ietf-ccamp-rwa-info-08.txt 2010-09-04 01:13:16.000000000 +0200 +++ 2/draft-ietf-ccamp-rwa-info-09.txt 2010-09-04 01:13:16.000000000 +0200 @@ -1,25 +1,25 @@ Network Working Group Y. Lee Internet Draft Huawei Intended status: Informational G. Bernstein -Expires: January 2011 Grotto Networking +Expires: March 2011 Grotto Networking D. Li Huawei W. Imajuku NTT - July 12, 2010 + September 3, 2010 Routing and Wavelength Assignment Information Model for Wavelength Switched Optical Networks - draft-ietf-ccamp-rwa-info-08.txt + draft-ietf-ccamp-rwa-info-09.txt 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. @@ -28,21 +28,21 @@ 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 January 12, 2011. + This Internet-Draft will expire on March 3, 2011. Copyright Notice Copyright (c) 2010 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 @@ -64,24 +64,25 @@ information that may be of use to other technologies utilizing a GMPLS control plane are discussed. Table of Contents 1. Introduction...................................................3 1.1. Revision History..........................................4 1.1.1. Changes from 01......................................4 1.1.2. Changes from 02......................................4 1.1.3. Changes from 03......................................4 - 1.1.4. Changes from 04......................................4 + 1.1.4. Changes from 04......................................5 1.1.5. Changes from 05......................................5 1.1.6. Changes from 06......................................5 1.1.7. Changes from 07......................................5 + 1.1.8. Changes from 08......................................5 2. Terminology....................................................5 3. Routing and Wavelength Assignment Information Model............6 3.1. Dynamic and Relatively Static Information.................6 4. Node Information (General).....................................7 4.1. Connectivity Matrix.......................................7 4.2. Shared Risk Node Group....................................8 5. Node Information (WSON specific)...............................8 5.1. Resource Accessibility/Availability.......................9 5.2. Resource Signal Constraints and Processing Capabilities..13 5.3. Compatibility and Capability Details.....................14 @@ -91,33 +92,34 @@ 5.3.4. Bit Rate Range List.................................14 5.3.5. Acceptable Client Signal List.......................15 5.3.6. Processing Capability List..........................15 6. Link Information (General)....................................15 6.1. Administrative Group.....................................16 6.2. Interface Switching Capability Descriptor................16 6.3. Link Protection Type (for this link).....................16 6.4. Shared Risk Link Group Information.......................16 6.5. Traffic Engineering Metric...............................16 6.6. Port Label (Wavelength) Restrictions.....................16 - 7. Dynamic Components of the Information Model...................18 - 7.1. Dynamic Link Information (General).......................18 - 7.2. Dynamic Node Information (WSON Specific).................19 - 8. Security Considerations.......................................19 - 9. IANA Considerations...........................................19 - 10. Acknowledgments..............................................19 - 11. References...................................................20 - 11.1. Normative References....................................20 - 11.2. Informative References..................................21 - 12. Contributors.................................................22 - Author's Addresses...............................................22 - Intellectual Property Statement..................................23 - Disclaimer of Validity...........................................24 + 6.6.1. Port-Wavelength Exclusivity Example.................18 + 7. Dynamic Components of the Information Model...................19 + 7.1. Dynamic Link Information (General).......................20 + 7.2. Dynamic Node Information (WSON Specific).................20 + 8. Security Considerations.......................................20 + 9. IANA Considerations...........................................21 + 10. Acknowledgments..............................................21 + 11. References...................................................22 + 11.1. Normative References....................................22 + 11.2. Informative References..................................23 + 12. Contributors.................................................24 + Author's Addresses...............................................24 + Intellectual Property Statement..................................25 + Disclaimer of Validity...........................................26 1. Introduction The purpose of the following information model for WSONs is to facilitate constrained lightpath computation and as such is not a general purpose network management information model. This constraint is frequently referred to as the "wavelength continuity" constraint, and the corresponding constrained lightpath computation is known as the routing and wavelength assignment (RWA) problem. Hence the information model must provide sufficient topology and wavelength @@ -199,20 +201,26 @@ Simplified information model for WSON specifics, by combining similar fields and introducing simpler aggregate information elements. 1.1.7. Changes from 07 Added shared fiber connectivity to resource pool modeling. This includes information for determining wavelength collision on an internal fiber providing access to resource blocks. + 1.1.8. Changes from 08 + + Added PORT_WAVELENGTH_EXCLUSIVITY in the RestrictionType parameter. + Added section 6.6.1 that has an example of the port wavelength + exclusivity constraint. + 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 @@ -400,50 +409,59 @@ was generally discussed in [WSON-Frame] and consisted of a matrix to indicate possible connectivity along with wavelength constraints for links/ports. Since regenerators or wavelength converters may be considered a scarce resource we will also want to our model to include as a minimum the usage state (availability) of individual regenerators or converters in the pool. Models that incorporate more state to further reveal blocking conditions on ingress or egress to particular converters are for further study and not included here. The three stage model as shown schematically in Figure 1 and Figure - 2. In this model we assume N ingress ports (fibers), P resource - blocks containing one or more identical resources (e.g. wavelength + 2.The difference between the two figures is that in Figure 1 we + assume that each signal that can get to a resource block may do so, + while in Figure 2 the access to the resource blocks is via a shared + fiber which imposes its own wavelength collision constraint. In the + representation of Figure 1 we can have more than one ingress to each + resource block since each ingress represents a single wavelength + signal, while in Figure 2 we show a single multiplexed WDM ingress, + e.g., a fiber, to each block. + + In this model we assume N ingress ports (fibers), P resource blocks + containing one or more identical resources (e.g. wavelength converters), and M egress ports (fibers). Since not all ingress ports can necessarily reach each resource block, the model starts with a resource pool ingress matrix RI(i,p) = {0,1} whether ingress port i can reach potentially reach resource block p. Since not all wavelengths can necessarily reach all the resources or the resources may have limited input wavelength range we have a set of relatively static ingress port constraints for each resource. In addition, if the access to a resource block is via a shared fiber - this would impose a dynamic wavelength availability constraints on - that shared fiber. We can model each resource block ingress port - constraint via a static wavelength set mechanism and in the case of - shared access to a block via another dynamic wavelength set - mechanism. + (Figure 2) this would impose a dynamic wavelength availability + constraint on that shared fiber. We can model each resource block + ingress port constraint via a static wavelength set mechanism and in + the case of shared access to a block via another dynamic wavelength + set mechanism. Next we have a state vector RA(j) = {0,...,k} which tells us the number of resources in resource block j in use. This is the only state kept in the resource pool model. This state is not necessary for modeling "fixed" transponder system or full OEO switches with WDM interfaces, i.e., systems where there is no sharing. After that, we have a set of static resource egress wavelength constraints and possibly dynamic shared egress fiber constraints. The static constraints indicate what wavelengths a particular resource block can generate or are restricted to generating e.g., a fixed regenerator would be limited to a single lambda. The dynamic constraints would be used in the case where a single shared fiber is - used to egress the resource block. + used to egress the resource block (Figure 2). Finally, we have a resource pool egress matrix RE(p,k) = {0,1} depending on whether the output from resource block p can reach egress port k. Examples of this method being used to model wavelength converter pools for several switch architectures from the literature are given in reference [WC-Pool]. I1 +-------------+ +-------------+ E1 ----->| | +--------+ | |-----> I2 | +------+ Rb #1 +-------+ | E2 @@ -726,26 +744,31 @@ The RestrictionType parameter is used to specify general port restrictions and matrix specific restrictions. It can take the following values and meanings: SIMPLE_WAVELENGTH: Simple wavelength set restriction; The wavelength set parameter is required. CHANNEL_COUNT: The number of channels is restricted to be less than or equal to the Max number of channels parameter (which is required). + PORT_WAVELENGTH_EXCLUSIVITY: A wavelength can be used at most once + among a given set of ports. The set of ports is specified as a + parameter to this constraint. + WAVEBAND1: Waveband device with a tunable center frequency and passband. This constraint is characterized by the MaxWaveBandWidth parameters which indicates the maximum width of the waveband in terms of channels. Note that an additional wavelength set can be used to indicate the overall tuning range. Specific center frequency tuning information can be obtained from dynamic channel in use information. + It is assumed that both center frequency and bandwidth (Q) tuning can be done without causing faults in existing signals. Restriction specific parameters are used with one or more of the previously listed restriction types. The currently defined parameters are: LabelSet is a conceptual set of labels (wavelengths). MaxNumChannels is the maximum number of channels that can be @@ -747,32 +770,85 @@ are: LabelSet is a conceptual set of labels (wavelengths). MaxNumChannels is the maximum number of channels that can be simultaneously used (relative to either a port or a matrix). MaxWaveBandWidth is the maximum width of a tunable waveband switching device. + PortSet is a conceptual set of ports. + For example, if the port is a "colored" drop port of a ROADM then we have two restrictions: (a) CHANNEL_COUNT, with MaxNumChannels = 1, and (b) SIMPLE_WAVELENGTH, with the wavelength set consisting of a single member corresponding to the frequency of the permitted wavelength. See [Switch] for a complete waveband example. This information model for port wavelength (label) restrictions is fairly general in that it can be applied to ports that have label restrictions only or to ports that are part of an asymmetric switch and have label restrictions. In addition, the types of label restrictions that can be supported are extensible. + 6.6.1. Port-Wavelength Exclusivity Example + + Although there can be many different ROADM or switch architectures + that can lead to the constraint where a lambda (label) maybe used at + most once on a set of ports Figure 3 shows a ROADM architecture based + on components known as a Wavelength Selective Switch (WSS)[OFC08]. + This ROADM is composed of splitters, combiners, and WSSes. This ROADM + has 11 egress ports, which are numbered in the diagram. Egress ports + 1-8 are known as drop ports and are intended to support a single + wavelength. Drop ports 1-4 egress from WSS #2, which is fed from WSS + #1 via a single fiber. Due to this internal structure a constraint is + placed on the egress ports 1-4 that a lambda can be only used once + over the group of ports (assuming uni-cast and not multi-cast + operation). Similarly we see that egress ports 5-8 have a similar + constraint due to the internal structure. + + | A + v 10 | + +-------+ +-------+ + | Split | |WSS 6 | + +-------+ +-------+ + +----+ | | | | | | | | + | W | | | | | | | | +-------+ +----+ + | S |--------------+ | | | +-----+ | +----+ | | S | + 9 | S |----------------|---|----|-------|------|----|---| p | + <--| |----------------|---|----|-------|----+ | +---| l |<-- + | 5 |--------------+ | | | +-----+ | | +--| i | + +----+ | | | | | +------|-|-----|--| t | + +--------|-+ +----|-|---|------|----+ | +----+ + +----+ | | | | | | | | | + | S |-----|--------|----------+ | | | | | | +----+ + | p |-----|--------|------------|---|------|----|--|--| W | + -->| l |-----|-----+ | +----------+ | | | +--|--| S |11 + | i |---+ | | | | +------------|------|-------|--| S |--> + | t | | | | | | | | | | +---|--| | + +----+ | | +---|--|-|-|------------|------|-|-|---+ | 7 | + | | | +--|-|-|--------+ | | | | | +----+ + | | | | | | | | | | | | + +------+ +------+ +------+ +------+ + | WSS 1| | Split| | WSS 3| | Split| + +--+---+ +--+---+ +--+---+ +--+---+ + | A | A + v | v | + +-------+ +--+----+ +-------+ +--+----+ + | WSS 2 | | Comb. | | WSS 4 | | Comb. | + +-------+ +-------+ +-------+ +-------+ + 1|2|3|4| A A A A 5|6|7|8| A A A A + v v v v | | | | v v v v | | | | + + Figure 3 A ROADM composed from splitter, combiners, and WSSs. + 7. Dynamic Components of the Information Model In the previously presented information model there are a limited number of information elements that are dynamic, i.e., subject to change with subsequent establishment and teardown of connections. Depending on the protocol used to convey this overall information model it may be possible to send this dynamic information separate from the relatively larger amount of static information needed to characterize WSON's and their network elements. @@ -874,20 +950,25 @@ [RFC5307] Kompella, K., Ed., and Y. Rekhter, Ed., "IS-IS Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 5307, October 2008. [WSON-Frame] Y. Lee, G. Bernstein, W. Imajuku, "Framework for GMPLS and PCE Control of Wavelength Switched Optical Networks", work in progress: draft-ietf-ccamp-rwa-wson-framework. 11.2. Informative References + [OFC08] P. Roorda and B. Collings, "Evolution to Colorless and + Directionless ROADM Architectures," Optical Fiber + communication/National Fiber Optic Engineers Conference, 2008. + OFC/NFOEC 2008. Conference on, 2008, pp. 1-3. + [Shared] G. Bernstein, Y. Lee, "Shared Backup Mesh Protection in PCE- based WSON Networks", iPOP 2008, http://www.grotto- networking.com/wson/iPOP2008_WSON-shared-mesh-poster.pdf . [Switch] G. Bernstein, Y. Lee, A. Gavler, J. Martensson, " Modeling WDM Wavelength Switching Systems for Use in GMPLS and Automated Path Computation", Journal of Optical Communications and Networking, vol. 1, June, 2009, pp. 187-195. [G.Sup39] ITU-T Series G Supplement 39, Optical system design and