Network Working Group G. Bernstein Internet Draft Grotto Networking Intended status: Informational Y. Lee Expires: April 2010 Huawei Ben Mack-Crane Huawei October 7, 2009 WSON Signal Characteristics and Network Element Compatibility Constraints for GMPLS draft-bernstein-ccamp-wson-compatibility-01.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. 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." 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Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the BSD License. Abstract While the current GMPLS WSON framework can deal with many types of wavelength switching systems there is a desire to extend the control plane to networks that include a combination of transparent optical and hybrid electro optical systems such as OEO switches, regenerators, and wavelength converters. Such networks are frequently referred to as translucent optical networks in the literature. Some of the systems use in such networks can be limited to processing WSON signals with specific characteristics or attributes. In addition, some of the network elements may be able to perform important optional processing functions such as regeneration on a signal and would need to be provisioned as part of optical path establishment. This document provides a WSON signal definition and attributes characterization based on ITU-T interface and signal class standards and describes the signal compatibility constraints of this extended set of network elements. The signal characterization, network element compatibility constraints and enhanced provisioning support enable GMPLS routing and signaling to control these devices and PCE to compute optical light-paths subject to signal compatibility attributes. Table of Contents 1. Introduction...................................................3 2. Describing Optical Signals in WSONs............................3 2.1. Optical Interfaces........................................4 2.2. Optical Tributary Signals.................................4 2.3. WSON Signal Characteristics...............................5 3. Electro-Optical Systems........................................6 3.1. Regenerators..............................................6 3.2. OEO Switches..............................................9 3.3. Wavelength Converters.....................................9 4. Characterizing WSON Network Elements..........................10 4.1. Input Constraints........................................10 4.2. Output Constraints.......................................11 4.3. Processing Capabilities..................................11 5. Networking Scenarios and the Control Plane....................12 Bernstein and Lee Expires April 7, 2010[Page 2] Internet-Draft Wavelength Switched Optical Networks October 2009 5.1. Fixed Regeneration Points................................12 5.2. Shared Regeneration Pools................................13 5.3. Reconfigurable Regenerators..............................13 5.4. Relation to Translucent Networks.........................13 6. Implications for GMPLS and PCE................................14 6.1. Link and Network Element Extensions for GMPLS Routing....14 6.2. Implications for GMPLS Signaling.........................15 6.3. PCEP Extensions..........................................16 7. Security Considerations.......................................17 8. IANA Considerations...........................................17 9. Acknowledgments...............................................17 10. References...................................................18 10.1. Normative References....................................18 10.2. Informative References..................................19 Author's Addresses...............................................19 Intellectual Property Statement..................................20 Disclaimer of Validity...........................................20 1. Introduction The current GMPLS WSON formalism can deal with many types of wavelength switching systems. However, there is an implicit assumption that all signals used in a WSON are compatible with all network elements. This arises in practice for a number of reasons (a) in some WSONs only one class of signal is used throughout the network, or (b) only "relatively" transparent network elements are utilized in the WSON. Assumption (a) limits the inherent flexibility that carriers seek from a WSON and assumption (b) leaves out very common optical network elements including regenerators, OEO switches, and wavelength converters. Therefore there is a requirement to extend the GMPLS control plane to allow both multiple WSON signal types and common hybrid electro optical systems. In the following we characterize WSON signals in line with ITU-T standards, and add attributes describing signal compatibility constraints to WSON network elements. This way the control plane signaling and path computation functions can ensure "signal" compatibility between source, sink and any links or network elements as part of the path selection process, and configure devices appropriately via signaling as part of the connection provisioning process. 2. Describing Optical Signals in WSONs As we will later see the new network elements that we wish to incorporate within the GMPLS control plane(OEO switches, regenerators, and wavelength converters) can impose constraints on the types of signals they can "process". Hence to enable the use of a Bernstein and Lee Expires April 7, 2010[Page 3] Internet-Draft Wavelength Switched Optical Networks October 2009 larger set of network elements the first step is to more precisely define and characterize our "optical signal". 2.1. Optical Interfaces In wavelength switched optical networks (WSONs) our fundamental unit of switching is intuitively that of a "wavelength". The transmitters and receivers in these networks will deal with one wavelength at a time, while the switching systems themselves can deal with multiple wavelengths at a time. Hence we are generally concerned with multichannel dense wavelength division multiplexing (DWDM) networks with single channel interfaces. Interfaces of this type are defined in ITU-T recommendations [G.698.1] and [G.698.1]. Key non-impairment related parameters defined in [G.698.1] and [G.698.2] are: (a) Minimum Channel Spacing (GHz) (b) Bit-rate/Line coding (modulation) of optical tributary signals (c) Minimum and Maximum central frequency We see that (a) and (c) above are related to properties of the link and have been modeled in [Otani], [WSON-FRAME], [WSON-Info] and (b) is related to the "signal". 2.2. Optical Tributary Signals The optical interface specifications [G.698.1], [G.698.2], and [G.959.1] all use the concept of an Optical Tributary Signal which is defined as "a single channel signal that is placed within an optical channel for transport across the optical network". Note the use of the qualifier "tributary" to indicate that this is a single channel entity and not a multichannel optical signal. This is our candidate terminology for the entity that we will be controlling in our GMPLS extensions for WSONs. There are a currently a number of different "flavors" of optical tributary signals, known as "optical tributary signal classes". These are currently characterized by a modulation format and bit rate range [G.959.1]: (a) optical tributary signal class NRZ 1.25G (b) optical tributary signal class NRZ 2.5G (c) optical tributary signal class NRZ 10G Bernstein and Lee Expires April 7, 2010[Page 4] Internet-Draft Wavelength Switched Optical Networks October 2009 (d) optical tributary signal class NRZ 40G (e) optical tributary signal class RZ 40G Note that with advances in technology more optical tributary signal classes may be added and that this is currently an active area for deployment and standardization. In particular at the 40G rate there are a number of non-standardized advanced modulation formats that have seen significant deployment including Differential Phase Shift Keying (DPSK) and Phase Shaped Binary Transmission (PSBT)[Winzer06]. Note that according to [G.698.2] it is important to fully specify the bit rate of the optical tributary signal: "When an optical system uses one of these codes, therefore, it is necessary to specify both the application code and also the exact bit rate of the system. In other words, there is no requirement for equipment compliant with one of these codes to operate over the complete range of bit rates specified for its optical tributary signal class." Hence we see that modulation format (optical tributary signal class) and bit rate are key in characterizing the optical tributary signal. 2.3. WSON Signal Characteristics We refer an optical tributary signal defined in ITU-T G.698.1 and .2 to as the signal in this document. This is an "entity" that can be put on an optical communications channel formed from links and network elements in a WSON. This corresponds to the "lambda" LSP in GMPLS. For signal compatibility purposes we will be interested in the following signal characteristics: List 1. WSON Signal Characteristics 1. Optical tributary signal class (modulation format). 2. FEC: whether forward error correction is used in the digital stream and what type of error correcting code is used 3. Center frequency (wavelength) 4. Bit rate 5. G-PID: General Protocol Identifier for the information format The first three items on this list can change as a WSON signal traverses a network with regenerators, OEO switches, or wavelength converters. An ability to control wavelength conversion already exists in GMPLS. Bernstein and Lee Expires April 7, 2010[Page 5] Internet-Draft Wavelength Switched Optical Networks October 2009 Bit rate and GPID would not change since they describe the encoded bit stream. A set of G-PID values are already defined for lambda switching in [RFC3471] and [RFC4328]. Note that a number of "pre-standard" or proprietary modulation formats and FEC codes are commonly used in WSONs. For some digital bit streams the presence of FEC can be detected, e.g., in [G.707] this is indicated in the signal itself via the FEC status indication (FSI) byte, while in [G.709] this can be inferred from whether the FEC field of the OTUk is all zeros or not. 3. Electro-Optical Systems This section describes how Electro-Optical Systems (e.g., OEO switches, wavelength converters, and regenerators) interact with the WSON signal characteristics defined in List 1 in Section 2.3. OEO switches, wavelength converters and regenerators all share a similar property: they can be more or less "transparent" to an "optical signal" depending on their functionality and/or implementation. Regenerators have been fairly well characterized in this regard so we start by describing their properties. 3.1. Regenerators The various approaches to regeneration are discussed in ITU-T G.872 Annex A [G.872]. They map a number of functions into the so-called 1R, 2R and 3R categories of regenerators as summarized in Table 1 below: Bernstein and Lee Expires April 7, 2010[Page 6] Internet-Draft Wavelength Switched Optical Networks October 2009 Table 1 Regenerator functionality mapped to general regenerator classes from [G.872]. --------------------------------------------------------------------- 1R | Equal amplification of all frequencies within the amplification | bandwidth. There is no restriction upon information formats. +----------------------------------------------------------------- | Amplification with different gain for frequencies within the | amplification bandwidth. This could be applied to both single- | channel and multi-channel systems. +----------------------------------------------------------------- | Dispersion compensation (phase distortion). This analogue | process can be applied in either single-channel or multi- | channel systems. --------------------------------------------------------------------- 2R | Any or all 1R functions. Noise suppression. +----------------------------------------------------------------- | Digital reshaping (Schmitt Trigger function) with no clock | recovery. This is applicable to individual channels and can be | used for different bit rates but is not transparent to line | coding (modulation). -------------------------------------------------------------------- 3R | Any or all 1R and 2R functions. Complete regeneration of the | pulse shape including clock recovery and retiming within | required jitter limits. -------------------------------------------------------------------- From the previous table we can see that 1R regenerators are generally independent of signal modulation format (also known as line coding), but may work over a limited range of wavelength/frequencies. We see that 2R regenerators are generally applicable to a single digital stream and are dependent upon modulation format (line coding) and to a lesser extent are limited to a range of bit rates (but not a specific bit rate). Finally, 3R regenerators apply to a single channel, are dependent upon the modulation format and generally sensitive to the bit rate of digital signal, i.e., either are designed to only handle a specific bit rate or need to be programmed to accept and regenerate a specific bit rate. In all these types of regenerators the digital bit stream contained within the optical or electrical signal is not modified. However, in the most common usage of regenerators the digital bit stream may be slightly modified for performance monitoring and fault management purposes. SONET, SDH and G.709 all have a digital signal "envelope" designed to be used between "regenerators" (in this case 3R regenerators). In SONET this is known as the "section" signal, in SDH this is known as the "regenerator section" signal, in G.709 this is known as an OTUk (Optical Channel Transport Unit-k). These Bernstein and Lee Expires April 7, 2010[Page 7] Internet-Draft Wavelength Switched Optical Networks October 2009 signals reserve a portion of their frame structure (known as overhead) for use by regenerators. The nature of this overhead is summarized in Table 2. Table 2. SONET, SDH, and G.709 regenerator related overhead. +-----------------------------------------------------------------+ |Function | SONET/SDH | G.709 OTUk | | | Regenerator | | | | Section | | |------------------+----------------------+-----------------------| |Signal | J0 (section | Trail Trace | |Identifier | trace) | Identifier (TTI) | |------------------+----------------------+-----------------------| |Performance | BIP-8 (B1) | BIP-8 (within SM) | |Monitoring | | | |------------------+----------------------+-----------------------| |Management | D1-D3 bytes | GCC0 (general | |Communications | | communications | | | | channel) | |------------------+----------------------+-----------------------| |Fault Management | A1, A2 framing | FAS (frame alignment | | | bytes | signal), BDI(backward| | | | defect indication)BEI| | | | (backward error | | | | indication) | +------------------+----------------------+-----------------------| |Forward Error | P1,Q1 bytes | OTUk FEC | |Correction (FEC) | | | +-----------------------------------------------------------------+ In the previous table we see support for frame alignment, signal identification, and FEC. What this table also shows by its omission is that no switching or multiplexing occurs at this layer. This is a significant simplification for the control plane since control plane standards require a multi-layer approach when there are multiple switching layers, but not for "layering" to provide the management functions of Table 2. That is, many existing technologies covered by GMPLS contain extra management related layers that are essentially ignored by the control plane (though not by the management plane!). Hence, the approach here is to include regenerators and other devices at the WSON layer unless they provide higher layer switching and then a multi-layer or multi-region approach [RFC5212] is called for. However, this can result in regenerators having a dependence on the client signal type. Bernstein and Lee Expires April 7, 2010[Page 8] Internet-Draft Wavelength Switched Optical Networks October 2009 Hence we see that depending upon the regenerator technology we may have the following constraints imposed by a regenerator device: Table 3. Regenerator Compatibility Constraints +--------------------------------------------------------+ | Constraints | 1R | 2R | 3R | +--------------------------------------------------------+ | Limited Wavelength Range | x | x | x | +--------------------------------------------------------+ | Modulation Type Restriction | | x | x | +--------------------------------------------------------+ | Bit Rate Range Restriction | | x | x | +--------------------------------------------------------+ | Exact Bit Rate Restriction | | | x | +--------------------------------------------------------+ | Client Signal Dependence | | | x | +--------------------------------------------------------+ Note that Limited Wavelength Range constraint is already modeled in GMPLS for WSON and that Modulation Type Restriction constraint includes FEC. 3.2. OEO Switches A common place where optical-to-electrical-to-optical (OEO) processing may take place is in WSON switches that utilize (or contain) regenerators. A vendor may add regenerators to a switching system for a number of reasons. One obvious reason is to restore signal quality either before or after optical processing (switching). Another reason may be to convert the signal to an electronic form for switching then reconverting to an optical signal prior to egress from the switch. In this later case the regeneration is applied to adapt the signal to the switch fabric regardless of whether or not it is needed from a signal quality perspective. In either case these optical switches have essentially the same compatibility constraints as those we described for regenerators in Table 3. 3.3. Wavelength Converters In [WSON-FRAME] the motivation for utilizing wavelength converters was discussed. In essence a wavelength converter would take one or Bernstein and Lee Expires April 7, 2010[Page 9] Internet-Draft Wavelength Switched Optical Networks October 2009 more optical channels on specific wavelengths and convert them to corresponding new specific wavelengths. Currently all optical wavelength converters exist but have not been widely deployed, hence the majority of wavelength converters are based on demodulation to an electrical signal and then re-modulation onto a new optical carrier, i.e., an OEO process. This process is very similar to that used for a regenerator except that the output optical wavelength will be different from the input optical wavelength. Hence in general wavelength converters have signal processing restrictions that are essentially the same as those we described for regenerators in Table 3 with perhaps an additional input frequency range restriction and output frequency range restriction. By additional we mean more restrictive than the range of the WDM link. Such a restriction has already been modeled in [WSON-Frame] and [WSON-Info]. 4. Characterizing WSON Network Elements In this section we characterize WSON network elements by the three key functional components: Input constraints, Output constraints and Processing Capabilities. WSON Network Element +-----------------------+ WSON Signal | | | | WSON Signal | | | | ---------------> | | | | -----------------> | | | | +-----------------------+ <-----> <-------> <-----> Input Processing Output Figure 1 WSON Network Element 4.1. Input Constraints Section 3 discussed the basic properties regenerators, OEO switches and wavelength converters from these we have the following possible types of input constraints and properties: 1. Acceptable Modulation formats 2. Client Signal (GPID) restrictions 3. Bit Rate restrictions 4. FEC coding restrictions Bernstein and Lee Expires April 7, 2010[Page 10] Internet-Draft Wavelength Switched Optical Networks October 2009 5. Configurability: (a) none, (b) self-configuring, (c) required We can represent these constraints via simple lists. Note that the device may need to be "provisioned" via signaling or some other means to accept signals with some attributes versus others. In other cases the devices maybe relatively transparent to some attributes, e.g., such as a 2R regenerator to bit rate. Finally, some devices maybe able to auto-detect some attributes and configure themselves, e.g., a 3R regenerator with bit rate detection mechanisms and flexible phase locking circuitry. To account for these different cases we've added item 5, which describes the devices configurability. Note that such input constraints also apply to the final destination, sink or termination, of the WSON signal. 4.2. Output Constraints None of the network elements considered here modifies either the bit rate or the basic type of the client signal. However, they may modify the modulation format or the FEC code. Typically we'd see the following types of output constraints: 1. Output modulation is the same as input modulation (default) 2. A limited set of output modulations is available 3. Output FEC is the same as input FEC code (default) 4. A limited set of output FEC codes is available Note that in cases (2) and (4) above, where there is more than one choice in the output modulation or FEC code then the network element will need to be configured on a per LSP basis as to which choice to use. 4.3. Processing Capabilities A general WSON network element (NE) can perform a number of signal processing functions including: (A) Regeneration (possibly different types) (B) Fault and Performance Monitoring (C) Wavelength Conversion (D) Switching Bernstein and Lee Expires April 7, 2010[Page 11] Internet-Draft Wavelength Switched Optical Networks October 2009 Items (C) and (D) are already covered in GMPLS and [WSON-Frame]. An NE may or may not have the ability to perform regeneration (of the one of the types previously discussed). In addition some nodes may have limited regeneration capability, i.e., a shared pool, which may be applied to selected signals traversing the NE. Hence to describe the regeneration capability of a link or node we have at a minimum: 1. Regeneration capability: (a)fixed, (b) selective, (c) none 2. Regeneration type: 1R, 2R, 3R 3. Regeneration pool properties for the case of selective regeneration (ingress & egress restrictions, availability) Note that the properties of shared regenerator pools would be essentially the same at that of wavelength converter pools modeled in [WSON-Frame]. Item (B), fault and performance monitoring, is typically outside the scope of the control plane. However, when the operations are to be performed on an LSP basis or as part of an LSP then the control plane can be of assistance in their configuration. Per LSP, per node, fault and performance monitoring examples include setting up a "section trace" (a regenerator overhead identifier) between two nodes, or intermediate optical performance monitoring at selected nodes along a path. 5. Networking Scenarios and the Control Plane In the following we look at various networking scenarios involving regenerators, OEO switches and wavelength converters. We group these scenarios roughly by type and number of extensions to the GMPLS control plane that would be required. 5.1. Fixed Regeneration Points In the simplest networking scenario involving regenerators, the regeneration is associated with a WDM link or entire node and is not optional, i.e., all signals traversing the link or node will be regenerated. This includes OEO switches since they provide regeneration on every port. There maybe input constraints and output constraints on the regenerators. Hence the path selection process will need to know from an IGP or other means the regenerator constraints so that it can choose a compatible path. For impairment aware routing and wavelength assignment (IA-RWA) the path selection process will also need to know Bernstein and Lee Expires April 7, 2010[Page 12] Internet-Draft Wavelength Switched Optical Networks October 2009 which links/nodes provide regeneration. Even for "regular" RWA, this regeneration information is useful since wavelength converters typically perform regeneration and the wavelength continuity constraint can be relaxed at such a point. Signaling does not need to be enhanced to include this scenario since there are no reconfigurable regenerator options on input, output or with respect to processing. 5.2. Shared Regeneration Pools In this scenario there are nodes with shared regenerator pools within the network in addition to fixed regenerators of the previous scenario. These regenerators are shared within a node and their application to a signal is optional. There are no reconfigurable options on either input or output. The only processing option is to "regenerate" a particular signal or not. Regenerator information in this case is used in path computation to select a path that ensures signal compatibility and IA-RWA criteria. To setup an LSP that utilizes a regenerator from a node with a shared regenerator pool we need to be able to indicate that regeneration is to take place at that particular node along the signal path. Such a capability currently does not exist in GMPLS signaling. 5.3. Reconfigurable Regenerators In this scenario we have regenerators that require configuration prior to use on an optical signal. We discussed previously that this could be due to a regenerator that must be configured to accept signals with different characteristics, for regenerators with a selection of output attributes, or for regenerators with additional optional processing capabilities. As in the previous scenarios we will need information concerning regenerator properties for selection of compatible paths and for IA- RWA computations. In addition during LSP setup we need to be able configure regenerator options at a particular node along the path. Such a capability currently does not exist in GMPLS signaling. 5.4. Relation to Translucent Networks In the literature networks that contain both transparent network elements such as reconfigurable optical add drop multiplexers (ROADMs) and electro-optical network elements such regenerators or OEO switches are frequently referred to as Translucent optical networks [Trans07]. Earlier work suggesting GMPLS extensions for Bernstein and Lee Expires April 7, 2010[Page 13] Internet-Draft Wavelength Switched Optical Networks October 2009 translucent optical networks can be found in [Yang05] while a more comprehensive evaluation of differing GMPLS control plane approaches to translucent networks can be found in [Sambo09]. Three main types of translucent optical networks have been discussed: 1. Transparent "islands" surrounded by regenerators. This is frequently seen when transitioning from a metro optical sub- network to a long haul optical sub-network. 2. Mostly transparent networks with a limited number of OEO ("opaque") nodes strategically placed. This takes advantage of the inherent regeneration capabilities of OEO switches. In the planning of such networks one has to determine the optimal placement of the OEO switches [Sen08]. 3. Mostly transparent networks with a limited number of optical switching nodes with "shared regenerator pools" that can be optionally applied to signals passing through these switches. These switches are sometimes called translucent nodes. All three of these types of translucent networks fit within either the networking scenarios of sections 5.1. and 5.2. above. And hence, can be accommodated by the GMPLS extensions suggested in this document. 6. Implications for GMPLS and PCE 6.1. Link and Network Element Extensions for GMPLS Routing Other drafts [WSON-FRAME],[WSON-Info] provide NE models that include switching asymmetry and port wavelength constraints here we add parameters to our existing node and link models to take into account input constraints, output constraints, and the signal processing capabilities of a NE. Input Constraints: 1. Permitted optical tributary signal classes: A list of optical tributary signal classes that can be processed by this network element or carried over this link. [configuration type] 2. Acceptable FEC codes [configuration type] Bernstein and Lee Expires April 7, 2010[Page 14] Internet-Draft Wavelength Switched Optical Networks October 2009 3. Acceptable Bit Rate Set: A list of specific bit rates or bit rate ranges that the device can accommodate. Coarse bit rate info is included with the optical tributary signal class restrictions. 4. Acceptable G-PID list: A list of G-PIDs corresponding to the "client" digital streams that is compatible with this device. Note that since the bit rate of the signal does not change over the LSP. We can make this an LSP parameter and hence this information would be available for any NE that needs to use it for configuration. Hence we do not need "configuration type" for the NE with respect to bit rate. Output Constraints: 1. Output modulation: (a)same as input, (b) list of available types 2. FEC options: (a) same as input, (b) list of available codes Processing Capabilities: 1. Regeneration: (a) 1R, (b) 2R, (c) 3R, (d)list of selectable regeneration types 2. Fault and Performance Monitoring (a)GPID particular capabilities TBD, (b) optical performance monitoring capabilities TBD. Note that such parameters could be specified on an (a) Network element wide basis, (b) a per port basis, (c) on a per regenerator basis. Typically such information has been on a per port basis, e.g., the GMPLS interface switching capability descriptor [RFC4202]. However, in [WSON-FRAME] we give examples of shared wavelength converters within a switching system, and hence this would be on a subsystem basis. The exact form would be defined in the [WSON-Info] and [WSON-Encoding] drafts. 6.2. Implications for GMPLS Signaling We saw in section 2.3. that a WSON signal at any point along its path can be characterized by the (a) modulation format, (b) FEC, (c) wavelength, (d)bit rate, and (d)G-PID. Currently G-PID, wavelength (via labels), and bit rate (via bandwidth encoding) are supported in [RFC3471] and [RFC3473]. These RFCs can accommodate the wavelength changing at any node along the LSP and can provide explicit control of wavelength converters. Bernstein and Lee Expires April 7, 2010[Page 15] Internet-Draft Wavelength Switched Optical Networks October 2009 In the fixed regeneration point scenario (section 5.1. ) no enhancements are required to signaling since there are no additional configuration options for the LSP at a node. In the case of shared regeneration pools (section 5.2. ) we need to be able to indicate to a node that it should perform regeneration on a particular signal. Viewed another way, for an LSP we want to specify that certain nodes along the path perform regeneration. Such a capability currently does not exist in GMPLS signaling. The case of configurable regenerators (section 5.3. ) is very similar to the previous except that now there are potentially many more items that we may want to configure on a per node basis for an LSP. Note that the techniques of [RFC5420] which allow for additional LSP attributes and their recording in an RRO object could be extended to allow for additional LSP attributes in an ERO. This could allow one to indicate where optional 3R regeneration should take place along a path, any modification of LSP attributes such as modulation format, or any enhance processing such as performance monitoring. 6.3. PCEP Extensions When requesting a path computation to PCE, the PCC should be able to indicate the following: o The GPID type of an LSP o The signal attributes at the transmitter (at the source): (i) modulation type; (ii) FEC type o The signal attributes at the receiver (at the sink): (i) modulation type; (ii) FEC type The PCE should be able to respond to the PCC with the following: o The conformity of the requested optical characteristics associated with the resulting LSP with the source, sink and NE along the LSP. o Additional LSP attributes modified along the path (e.g., modulation format change, etc.) Bernstein and Lee Expires April 7, 2010[Page 16] Internet-Draft Wavelength Switched Optical Networks October 2009 7. Security Considerations This document has no requirement for a change to the security models within GMPLS and associated protocols. That is the OSPF-TE, RSVP-TE, and PCEP [RFC5540] security models could be operated unchanged. Furthermore the additional information distributed in order to extend GMPLS capabilities to the additional network elements discussed in this document represents a disclosure of network capabilities that an operator may wish to keep private. Consideration should be given to securing this information. 8. IANA Considerations This document makes no request for IANA actions. 9. Acknowledgments This document was prepared using 2-Word-v2.0.template.dot. Bernstein and Lee Expires April 7, 2010[Page 17] Internet-Draft Wavelength Switched Optical Networks October 2009 10. References 10.1. Normative References [RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description", RFC 3471, January 2003. [RFC4202] Kompella, K. and Y. Rekhter, "Routing Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4202, October 2005. [RFC4328] Papadimitriou, D., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Extensions for G.709 Optical Transport Networks Control", RFC 4328, January 2006. [G.694.1] ITU-T Recommendation G.694.1, "Spectral grids for WDM applications: DWDM frequency grid", June, 2002. [RFC5212] Shiomoto, K., Papadimitriou, D., Le Roux, JL., Vigoureux, M., and D. Brungard, "Requirements for GMPLS-Based Multi- Region and Multi-Layer Networks (MRN/MLN)", RFC 5212, July 2008. [RFC5540] J.P. Vasseur and J.L. Le Roux (Editors), "Path Computation Element (PCE) Communication Protocol (PCEP)", RFC 5540, March 2009. [WSON-FRAME] Y. Lee, G. Bernstein, W. Imajuku, "Framework for GMPLS and PCE Control of Wavelength Switched Optical Networks (WSON)", draft-ietf-ccamp-rwa-wson-framework-02.txt, March 2009. [WSON-Info] Y. Lee, G. Bernstein, D. Li, W. Imajuku, "Routing and Wavelength Assignment Information for Wavelength Switched Optical Networks", draft-bernstein-ccamp-wson-info-03.txt, March, 2009. [WSON-Encoding] G. Bernstein, Y. Lee, D. Li, W. Imajuku, "Routing and Wavelength Assignment Information Encoding for Wavelength Switched Optical networks", work in progress, draft-ietf- ccamp-rwa-wson-encode-01.txt, March 2009. Bernstein and Lee Expires April 7, 2010[Page 18] Internet-Draft Wavelength Switched Optical Networks October 2009 10.2. Informative References [Otani] T. Otani, H. Guo, K. Miyazaki, D. Caviglia, "Generalized Labels for G.694 Lambda-Switching Capable Label Switching Routers (LSR)", work in progress, draft-ietf-ccamp-gmpls-g- 694-lambda-labels-04.txt [G.872] ITU-T Recommendation G.872, Architecture of optical transport networks, November 2001. [G.959.1] ITU-T Recommendation G.959.1, Optical Transport Network Physical Layer Interfaces, March 2006. [Imp-Frame] G. Bernstein, Y. Lee, D. Li, G. Martinelli, "A Framework for the Control and Measurement of Wavelength Switched Optical Networks (WSON) with Impairments", Work in Progress, draft-ietf-ccamp-wson-impairments-00.txt. [Sambo09] N. Sambo, N. Andriolli, A. Giorgetti, L. Valcarenghi, I. Cerutti, P. Castoldi, and F. Cugini, "GMPLS-controlled dynamic translucent optical networks," Network, IEEE, vol. 23, 2009, pp. 34-40. [Sen08] A. Sen, S. Murthy, and S. Bandyopadhyay, "On Sparse Placement of Regenerator Nodes in Translucent Optical Network," Global Telecommunications Conference, 2008. IEEE GLOBECOM 2008. IEEE, 2008, pp. 1-6. [Trans07] Gangxiang Shen and Rodney S. Tucker, "Translucent optical networks: the way forward [Topics in Optical Communications]," Communications Magazine, IEEE, vol. 45, 2007, pp. 48-54. [Yang05] Xi Yang and B. Ramamurthy, "Dynamic routing in translucent WDM optical networks: the intradomain case," Lightwave Technology, Journal of, vol. 23, 2005, pp. 955-971. Author's Addresses Greg M. Bernstein Grotto Networking Fremont California, USA Phone: (510) 573-2237 Email: gregb@grotto-networking.com Bernstein and Lee Expires April 7, 2010[Page 19] Internet-Draft Wavelength Switched Optical Networks October 2009 Young Lee Huawei Technologies 1700 Alma Drive, Suite 100 Plano, TX 75075 USA Phone: (972) 509-5599 (x2240) Email: ylee@huawei.com T. Benjamin Mack-Crane Huawei Technologies Downers Grove, Illinois Email: tmackcrane@huawei.com Intellectual Property Statement The IETF Trust 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 any IETF 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. Copies of Intellectual Property 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 any standard or specification contained in an IETF Document. Please address the information to the IETF at ietf-ipr@ietf.org. Disclaimer of Validity All IETF Documents and the information contained therein 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 THEREIN WILL NOT INFRINGE Bernstein and Lee Expires April 7, 2010[Page 20] Internet-Draft Wavelength Switched Optical Networks October 2009 ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Bernstein and Lee Expires April 7, 2010[Page 21]