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Martinelli 3 Internet-Draft M. Kattan 4 Intended status: Informational G. Galimberti 5 Expires: January 31, 2013 Cisco 6 A. Zanardi 7 CREATE-NET 8 July 30, 2012 10 Information Model for Wavelength Switched Optical Networks (WSON) with 11 Optical Impairments Validation. 12 draft-martinelli-ccamp-wson-iv-info-00 14 Abstract 16 This document defines the Information Model to support Impairment- 17 Aware (IA) Routing an Wavelength Assignment (RWA) function. This 18 operation might be required in Wavelength Switched Optical Networks 19 (WSON) that already support RWA and the Information model defined 20 here goes in addition and it is fully compatible with the already 21 defined information model for WSON. 23 This information model shall support all control plane architectural 24 options defined for WSON with impairment validation. 26 Status of this Memo 28 This Internet-Draft is submitted in full conformance with the 29 provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF). Note that other groups may also distribute 33 working documents as Internet-Drafts. The list of current Internet- 34 Drafts is at http://datatracker.ietf.org/drafts/current/. 36 Internet-Drafts are draft documents valid for a maximum of six months 37 and may be updated, replaced, or obsoleted by other documents at any 38 time. It is inappropriate to use Internet-Drafts as reference 39 material or to cite them other than as "work in progress." 41 This Internet-Draft will expire on January 31, 2013. 43 Copyright Notice 45 Copyright (c) 2012 IETF Trust and the persons identified as the 46 document authors. All rights reserved. 48 This document is subject to BCP 78 and the IETF Trust's Legal 49 Provisions Relating to IETF Documents 50 (http://trustee.ietf.org/license-info) in effect on the date of 51 publication of this document. Please review these documents 52 carefully, as they describe your rights and restrictions with respect 53 to this document. Code Components extracted from this document must 54 include Simplified BSD License text as described in Section 4.e of 55 the Trust Legal Provisions and are provided without warranty as 56 described in the Simplified BSD License. 58 Table of Contents 60 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 61 1.1. Requirements Language . . . . . . . . . . . . . . . . . . . 3 62 2. Properties of an Impairment Information Model . . . . . . . . . 3 63 3. Background from WSON Information Model . . . . . . . . . . . . 5 64 4. Optical Impairment Information Model . . . . . . . . . . . . . 5 65 4.1. Node Information . . . . . . . . . . . . . . . . . . . . . 6 66 4.2. Link Information . . . . . . . . . . . . . . . . . . . . . 7 67 5. Encoding Considerations . . . . . . . . . . . . . . . . . . . . 7 68 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 8 69 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 70 8. Security Considerations . . . . . . . . . . . . . . . . . . . . 8 71 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 72 9.1. Normative References . . . . . . . . . . . . . . . . . . . 8 73 9.2. Informative References . . . . . . . . . . . . . . . . . . 8 74 Appendix A. G.680 Essential information . . . . . . . . . . . . . 9 75 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9 77 1. Introduction 79 In the context of Wavelength Switched Optical Network (WSON), 80 [RFC6163] defines the basic framework for a GMPLS control plane. The 81 associated info model [I-D.ietf-ccamp-rwa-info] defines all 82 parameters required for the related RWA process. These references 83 are the foundation but they do not consider the Optical Impairment 84 case. 86 In case of WSON where optical impairments plays a significant role, 87 the framework document [RFC6566] defines related control plane 88 architectural options for an Impairment Aware routing and wavelength 89 assignment (IA-RWA). Options include different combinations of 90 Impairment Validation (IV) and RWA functions through control plane 91 elements and operations (PCE, Routing, Signaling). 93 This document intent to provide the information model for the 94 impairment aware case to allow the impairment validation function. 95 It goes in addition with [I-D.ietf-ccamp-rwa-info] and the model 96 itself is independ of any architectural option described by the 97 framework and shall support all of them. 99 Models for the optical impairments are defined by ITU and the only 100 available models are reported in [ITU.G680] to cover only the linear 101 impairment case while non-linear case is left for further study. The 102 information model defined here however provide a generic enough 103 mechanism that could be easily extended to additional impairments 104 models. 106 1.1. Requirements Language 108 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 109 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 110 document are to be interpreted as described in RFC 2119 [RFC2119]. 112 2. Properties of an Impairment Information Model 114 An information model may have several attributes or properties that 115 need to be defined for each optical parameter made available to the 116 control plane. The properties will help to determine how the control 117 plane can deal with it depending on architectural options chosen 118 within the overall impairment framework [RFC6566]. In some case 119 properties value will help to identify the level of approximation 120 supported by the IV process. 122 o Time Dependency. 123 This will identify how the impairment may vary with time. There 124 could be cases where there is no time dependency, while in other 125 cases there may be need of impairment re- evaluation after a 126 certain time. In this category, variations in impairments due to 127 environmental factors such as those discussed in [G.sup47] are 128 considered. In some cases a level of approximation will consider 129 an impairment that has time dependency as constant. In this 130 Information Model we do neglect this property. 132 o Wavelength Dependency. 133 This property will identify if an impairment value can be 134 considered as constant over all the wavelength spectrum of 135 interest or if it has different values. Also in this case a 136 detailed impairment evaluation might lead to consider the exact 137 value while an approximation IV might take a constant value for 138 all wavelengths. In this Information Model we consider both case: 139 dependency / not dependency from a specific wavelengths. This 140 property may appear directly in the Information model definitions 141 or in the related encoding. 143 o Linearity. 144 As impairments are representation of physical effects there are 145 some that have a linear behavior while other are non-linear. 146 Linear approximation is in scope of scenario C of [RFC6566]. The 147 linearity implies the additivity optical quantities considered 148 during an Impairment Validation process. As an additional 149 approximation level, non-linear impairments as contribution into 150 linear ones. This Information Model deals with the linear 151 properties of optical impairments. 153 o Multi-Channel. 154 There are cases where a channel's impairments take different 155 values depending on the aside wavelengths already in place. In 156 this case a dependency among different LSP is introduced and is 157 typically a result of linear effects. This Information Model 158 neglect this effects on neighbor LSPs. 160 The following table summarize the above considerations where in the 161 first column reports the list of properties to be considered for each 162 optical parameters, while second column state if this property is 163 taken into account or not by this Information Model. 165 +-----------------------+----------------------+ 166 | Property | Info Model Awareness | 167 +-----------------------+----------------------+ 168 | Time Dependency | no | 169 | Wavelength Dependency | yes | 170 | Linearity | yes | 171 | Multi-channel | no | 172 +-----------------------+----------------------+ 174 Table 1: Optical Impairment Properties 176 3. Background from WSON Information Model 178 In this section we report terms already defined for the WSON-RWA (not 179 impairment aware) as in [I-D.ietf-ccamp-rwa-info] and 180 [I-D.ietf-ccamp-general-constraint-encode]. The purpose is to 181 provide essential information that will be reused or extended for the 182 impairment case. 184 In particular [I-D.ietf-ccamp-rwa-info] defines the connectivity 185 matrix as the follow: 187 ConnectivityMatrix ::= 189 However according to [I-D.ietf-ccamp-general-constraint-encode] this 190 definitions can be further detailed as: 192 ConnectivityMatrix ::= 193 (( ) ...) 195 This second definition highlights how the connectivity matrix is 196 built by pairs of LinkSet objects identifying the internal node 197 connectivity capability. 199 As a additional note, Connectivity Matrix belong to Node Information. 201 4. Optical Impairment Information Model 203 The idea behind this Information Model is to reuse the concept of the 204 Connectivity Matrix and defines an Impairment Matrix that summarize 205 optical impairments provided by the Node. 207 The goal of the information model is not to rephrase content from 208 [ITU.G680] but only provide necessary building blocks that allow the 209 IW-RWA process to apply the computational model defined by such 210 recommendation. Then the [ITU.G680] model defined in section 9 211 provide information to calculate the following parameters: 213 o OSNR. Section 9.1 215 o Chromatic Dispersion (CD). Section 9.2 217 o Polarization Mode Dispersion (PMD). Section 9.3 219 o Polarization Dependent Loss (PDL). Section 9.3 221 It should be noted that [ITU.G697] already defines an encoding for 222 all these parameters and in Section 5 we report some encoding 223 consideration. The [ITU.G697] is mainly oriented for monitoring so 224 the purpose is only reuse parameter definitions for those parameters 225 required by Impairment Validation process. 227 The information model defined here make the assumption that the 228 Optical Node is able to provide it's own contribution to such 229 parameters. To this extend the information model intentionally 230 ignore all internal detailed parameters that are used to by the 231 formulas. As an additional note, as reported in in [ITU.G680] 232 Section 10, each parameter can be reported as an OSNR contribution, 233 in such way the Optical Node not necessarily embed optical 234 computational capability but can provide an approximated contribution 235 to optical impairments. 237 With the above considerations this Information Model is able provide 238 an abstract view for an optical node to enable WSON protocol 239 extension with optical impairments validation. 241 4.1. Node Information 243 This model defines the Impairment Matrix as the following: 245 ImpairmentMatrix ::= 246 (( ) ...) 248 Where: 250 MatrixID. Is a unique identifier for the Matrix. This ID shall 251 be unique in scope among all connectivity matrix defined in 252 [I-D.ietf-ccamp-rwa-info] and all impairment matrix defined here. 254 ConnType. The type of matrix. Since values 0 and 1 are already 255 defined. This document defines the value 2. 257 LinkSet. Same object definition and usage as 258 [I-D.ietf-ccamp-general-constraint-encode]. 260 ImpairmentVector is defined as list of optical parmeters associated 261 to the internal node connection. 263 ImpairmentVector ::= ... 265 The set of OPTICAL_PARAM is identified by [ITU.G697] since they match 266 with parameters required by the linear impairments evaluation 267 provided by [ITU.G680]. This info model does not preclude any of 268 such parameters and eventually new parameters can be added to the 269 list. 271 4.2. Link Information 273 Currently not evaluated yet any information is required at Link Level 274 however the same approach can be used as in case of Node Information 275 section. The Link information defined in [I-D.ietf-ccamp-rwa-info] 276 is extend in the following way: 278 ::= 279 [] 280 282 With ImpairmentVector defined as previous section. 284 5. Encoding Considerations 286 Details about encoding will be defined in a separate document however 287 worth remembering that, within [ITU.G697] Appending V, ITU already 288 provides a guideline for encoding some optical parameters. 290 In particular [ITU.G697] indicates that each parameters shall be 291 represented by a 32 bit floating point number. 293 As an additional consideration, actual values for parameters defined 294 in the information models are provided by the Optical Node and it 295 could provide by direct measurement or from some internal computation 296 starting from indirect measurement. In any case the encoding shall 297 provide an the possibility to associate a variance with the 298 parameter. This information will enable the function implementing 299 IV-RWA process to make some additional considerations on wavelength 300 feasibility. 302 6. Acknowledgements 304 TBD 306 7. IANA Considerations 308 This document does not have ant IANA requirement. 310 8. Security Considerations 312 All drafts are required to have a security considerations section. 313 See RFC 3552 [RFC3552] for a guide. 315 9. References 317 9.1. Normative References 319 [ITU.G680] 320 International Telecommunications Union, "Physical transfer 321 functions of optical network elements", ITU- 322 T Recommendation G.680, July 2007. 324 [ITU.G697] 325 International Telecommunications Union, "Optical 326 monitoring for dense wavelength division multiplexing 327 systems", ITU-T Recommendation G.697, February 2012. 329 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 330 Requirement Levels", BCP 14, RFC 2119, March 1997. 332 9.2. Informative References 334 [I-D.ietf-ccamp-general-constraint-encode] 335 Bernstein, G., Lee, Y., Li, D., and W. Imajuku, "General 336 Network Element Constraint Encoding for GMPLS Controlled 337 Networks", draft-ietf-ccamp-general-constraint-encode-08 338 (work in progress), July 2012. 340 [I-D.ietf-ccamp-rwa-info] 341 Lee, Y., Bernstein, G., Li, D., and W. Imajuku, "Routing 342 and Wavelength Assignment Information Model for Wavelength 343 Switched Optical Networks", draft-ietf-ccamp-rwa-info-14 344 (work in progress), March 2012. 346 [I-D.narten-iana-considerations-rfc2434bis] 347 Narten, T. and H. Alvestrand, "Guidelines for Writing an 348 IANA Considerations Section in RFCs", 349 draft-narten-iana-considerations-rfc2434bis-09 (work in 350 progress), March 2008. 352 [RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629, 353 June 1999. 355 [RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC 356 Text on Security Considerations", BCP 72, RFC 3552, 357 July 2003. 359 [RFC6163] Lee, Y., Bernstein, G., and W. Imajuku, "Framework for 360 GMPLS and Path Computation Element (PCE) Control of 361 Wavelength Switched Optical Networks (WSONs)", RFC 6163, 362 April 2011. 364 [RFC6566] Lee, Y., Bernstein, G., Li, D., and G. Martinelli, "A 365 Framework for the Control of Wavelength Switched Optical 366 Networks (WSONs) with Impairments", RFC 6566, March 2012. 368 Appendix A. G.680 Essential information 370 TBD if we need some info instead of reading [ITU.G680] 372 Authors' Addresses 374 Giovanni Martinelli 375 Cisco 376 via Philips 12 377 Monza, 20900 378 Italy 380 Phone: +39 039 2092044 381 Email: giomarti@cisco.com 382 Moustafa Kattan 383 Cisco 384 DUBAI, 500321 385 UNITED ARAB EMIRATES 387 Phone: 388 Email: mkattan@cisco.com 390 Gabriele M. Galimberti 391 Cisco 392 Via Philips,12 393 Monza 20900 394 Italy 396 Phone: +39 039 2091462 397 Email: ggalimbe@cisco.com 399 Andrea Zanardi 400 CREATE-NET 401 via alla Cascata 56 C, Povo 402 Trento 38100 403 Italy 405 Email: andrea.zanardi@create-net.org