Network Working Group Y. Lee, Ed. Internet Draft Huawei Technologies Intended status: Standard R. Casellas, Ed. Expires: February 2017 CTTC August 15, 2016 PCEP Extension for WSON Routing and Wavelength Assignment draft-ietf-pce-wson-rwa-ext-05.txt Abstract This document provides the Path Computation Element communication Protocol (PCEP) extensions for the support of Routing and Wavelength Assignment (RWA) in Wavelength Switched Optical Networks (WSON). Lightpath provisioning in WSONs requires a routing and wavelength assignment (RWA) process. From a path computation perspective, wavelength assignment is the process of determining which wavelength can be used on each hop of a path and forms an additional routing constraint to optical light path computation. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt Lee & Casellas Expires February 15, 2017 [Page 1] Internet-Draft PCEP Extension for WSON RWA August 2016 The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on February 15, 2017. Copyright Notice Copyright (c) 2015 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 carefully, as they describe your rights and restrictions with respect to this document. 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 Simplified BSD License. Table of Contents 1. Terminology....................................................3 2. Requirements Language..........................................3 3. Introduction...................................................3 4. Encoding of a RWA Path Request.................................6 4.1. Wavelength Assignment (WA) Object.........................6 4.2. Wavelength Selection TLV..................................8 4.3. Wavelength Restriction Constraint TLV.....................8 4.3.1. Link Identifier Field...............................10 4.3.2. Wavelength Restriction Field........................12 4.4. Signal processing capability restrictions................13 4.4.1. Signal Processing Exclusion XRO Sub-Object..........14 4.4.2. IRO sub-object: signal processing inclusion.........14 5. Encoding of a RWA Path Reply..................................15 5.1. Error Indicator..........................................16 5.2. NO-PATH Indicator........................................17 6. Manageability Considerations..................................17 6.1. Control of Function and Policy...........................17 6.2. Information and Data Models, e.g. MIB module.............18 6.3. Liveness Detection and Monitoring........................18 6.4. Verifying Correct Operation..............................18 6.5. Requirements on Other Protocols and Functional Components18 6.6. Impact on Network Operation..............................18 Lee & Casellas Expires February 15,2017 [Page 2] Internet-Draft PCEP Extension for WSON RWA August 2016 7. Security Considerations.......................................18 8. IANA Considerations...........................................19 8.1. New PCEP Object..........................................19 8.2. New PCEP TLV: Wavelength Selection TLV...................19 8.3. New PCEP TLV: Wavelength Restriction Constraint TLV......19 8.4. New PCEP TLV: Wavelength Allocation TLV..................20 8.5. New PCEP TLV: Optical Interface Class List TLV...........20 8.6. New PCEP TLV: Client Signal TLV..........................20 8.7. New No-Path Reasons......................................21 8.8. New Error-Types and Error-Values.........................21 9. Acknowledgments...............................................22 10. References...................................................22 10.1. Informative References..................................22 10.2. Normative References....................................23 11. Contributors.................................................24 Authors' Addresses...............................................25 1. Terminology This document uses the terminology defined in [RFC4655], and [RFC5440]. 2. Requirements Language 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 [RFC2119]. 3. Introduction [RFC4655] defines a PCE based path computation architecture and explains how a Path Computation Element (PCE) may compute Label Switched Paths (LSP) in Multiprotocol Label Switching Traffic Engineering (MPLS-TE) and Generalized MPLS (GMPLS) networks at the request of Path Computation Clients (PCCs). A PCC is said to be any network component that makes such a request and may be, for instance, an Optical Switching Element within a Wavelength Division Multiplexing (WDM) network. The PCE, itself, can be located anywhere within the network, and may be within an optical switching element, a Network Management System (NMS) or Operational Support System (OSS), or may be an independent network server. Lee & Casellas Expires February 15,2017 [Page 3] Internet-Draft PCEP Extension for WSON RWA August 2016 The PCE communications Protocol (PCEP) is the communication protocol used between a PCC and a PCE, and may also be used between cooperating PCEs. [RFC4657] sets out the common protocol requirements for PCEP. Additional application-specific requirements for PCEP are deferred to separate documents. This document provides the PCEP extensions for the support of Routing and Wavelength Assignment (RWA) in Wavelength Switched Optical Networks (WSON) based on the requirements specified in [RFC7449]. WSON refers to WDM based optical networks in which switching is performed selectively based on the wavelength of an optical signal. In this document, it is assumed that wavelength converters require electrical signal regeneration. Consequently, WSONs can be transparent (A transparent optical network is made up of optical devices that can switch but not convert from one wavelength to another, all within the optical domain) or translucent (3R regenerators are sparsely placed in the network). A LSC Label Switched Path (LSP) may span one or several transparent segments, which are delimited by 3R regenerators (typically with electronic regenerator and optional wavelength conversion). Each transparent segment or path in WSON is referred to as an optical path. An optical path may span multiple fiber links and the path should be assigned the same wavelength for each link. In such case, the optical path is said to satisfy the wavelength-continuity constraint. Figure 1 illustrates the relationship between a LSC LSP and transparent segments (optical paths). +---+ +-----+ +-----+ +-----+ +-----+ | |I1 | | | | | | I2| | | |o------| |-------[(3R) ]------| |--------o| | | | | | | | | | | | +---+ +-----+ +-----+ +-----+ +-----+ [X LSC] [LSC LSC] [LSC LSC] [LSC X] SwCap <-------> <-------> <-----> <-------> <-----------------------><----------------------> Transparent Segment Transparent Segment <-------------------------------------------------> LSC LSP Figure 1 Illustration of a LSC LSP and transparent segments Lee & Casellas Expires February 15,2017 [Page 4] Internet-Draft PCEP Extension for WSON RWA August 2016 Note that two optical paths within a WSON LSP need not operate on the same wavelength (due to the wavelength conversion capabilities). Two optical paths that share a common fiber link cannot be assigned the same wavelength. To do otherwise would result in both signals interfering with each other. Note that advanced additional multiplexing techniques such as polarization based multiplexing are not addressed in this document since the physical layer aspects are not currently standardized. Therefore, assigning the proper wavelength on a lightpath is an essential requirement in the optical path computation process. When a switching node has the ability to perform wavelength conversion, the wavelength-continuity constraint can be relaxed, and a LSC Label Switched Path (LSP) may use different wavelengths on different links along its route from origin to destination. It is, however, to be noted that wavelength converters may be limited due to their relatively high cost, while the number of WDM channels that can be supported in a fiber is also limited. As a WSON can be composed of network nodes that cannot perform wavelength conversion, nodes with limited wavelength conversion, and nodes with full wavelength conversion abilities, wavelength assignment is an additional routing constraint to be considered in all lightpath computation. For example (see Figure 1), within a translucent WSON, a LSC LSP may be established between interfaces I1 and I2, spanning 2 transparent segments (optical paths) where the wavelength continuity constraint applies (i.e. the same unique wavelength MUST be assigned to the LSP at each TE link of the segment). If the LSC LSP induced a Forwarding Adjacency / TE link, the switching capabilities of the TE link would be [X X] where X < LSC (PSC, TDM, ...). This document aligns with GMPLS extensions for PCEP [PCEP-GMPLS] for generic property such as label, label-set and label assignment noting that wavelength is a type of label. Wavelength restrictions and constraints are also formulated in terms of labels per [RFC7579]. The optical modulation properties, which are also referred to as signal compatibility, are already considered in signaling in [RFC7581] and [RFC7688]. In order to improve the signal quality and limit some optical effects several advanced modulation processing are used. Those modulation properties contribute not only to optical signal quality checks but also constrain the selection of sender and receiver, as they should have matching signal processing capabilities. This document includes signal compatibility constraints as part of RWA path computation. That is, the signal Lee & Casellas Expires February 15,2017 [Page 5] Internet-Draft PCEP Extension for WSON RWA August 2016 processing capabilities (e.g., modulation and FEC) by the means of optical interface class (OIC) must be compatible between the sender and the receiver of the optical path across all optical elements. This document, however, does not address optical impairments as part of RWA path computation. See [WSON-Imp] and [RSVP-Imp] for more information on optical impairments and GMPLS. 4. Encoding of a RWA Path Request Figure 2 shows one typical PCE based implementation, which is referred to as the Combined Process (R&WA). With this architecture, the two processes of routing and wavelength assignment are accessed via a single PCE. This architecture is the base architecture from which the requirements have been specified in [RFC7449] and the PCEP extensions that are going to be specified in this document based on this architecture. +----------------------------+ +-----+ | +-------+ +--+ | | | | |Routing| |WA| | | PCC |<----->| +-------+ +--+ | | | | | +-----+ | PCE | +----------------------------+ Figure 2 Combined Process (R&WA) architecture 4.1. Wavelength Assignment (WA) Object Wavelength allocation can be performed by the PCE by different means: (a) By means of Explicit Label Control (ELC) where the PCE allocates which label to use for each interface/node along the path. in the sense that the allocated labels MAY appear after an interface route subobject. (b) By means of a Label Set where the PCE provides a range of potential labels to allocate by each node along the path. Option (b) allows distributed label allocation (performed during signaling) to complete wavelength assignment. Lee & Casellas Expires February 15,2017 [Page 6] Internet-Draft PCEP Extension for WSON RWA August 2016 Additionally, given a range of potential labels to allocate, the request SHOULD convey the heuristic / mechanism to the allocation. The format of a PCReq message after incorporating the WA object is as follows: ::= [] Where: ::=[] ::= [other optional objects...] If the WA object is present in the request, it MUST be encoded after the ENDPOINTS object. The format of the Wavelength Assignment (WA) object body is as follows: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Flags |M| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Wavelength Selection TLV | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Wavelength Restriction Constraint TLV | . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // Optional TLVs // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Lee & Casellas Expires February 15,2017 [Page 7] Internet-Draft PCEP Extension for WSON RWA August 2016 Figure 3 WA Object o Flags (32 bits) The following new flags SHOULD be set . M (Mode - 1 bit): M bit is used to indicate the mode of wavelength assignment. When M bit is set to 1, this indicates that the label assigned by the PCE must be explicit. That is, the selected way to convey the allocated wavelength is by means of Explicit Label Control (ELC) [RFC4003] for each hop of a computed LSP. Otherwise, the label assigned by the PCE needs not be explicit (i.e., it can be suggested in the form of label set objects in the corresponding response, to allow distributed WA. In such case, the PCE MUST return a Label Set Field as described in Section 2.6 of [RFC7579] in the response. See Section 5 of this document for the encoding discussion of a Label Set Field in a PCRep message. 4.2. Wavelength Selection TLV The Wavelength Selection TLV is used to indicate the wavelength selection constraint in regard to the order of wavelength assignment to be returned by the PCE. This TLV is only applied when M bit is set to ''explicit'' in the WA Object specified in Section 4.1. The encoding of this TLV is specified as the Wavelength Selection Sub-TLV in Section 4.2.2 of [RFC7689]. 4.3. Wavelength Restriction Constraint TLV For any request that contains a wavelength assignment, the requester (PCC) MUST be able to specify a restriction on the wavelengths to be used. This restriction is to be interpreted by the PCE as a constraint on the tuning ability of the origination laser transmitter or on any other maintenance related constraints. Note that if the LSP LSC spans different segments, the PCE MUST have mechanisms to know the tunability restrictions of the involved wavelength converters / regenerators, e.g. by means of the TED either via IGP or NMS. Even if the PCE knows the tunability of the transmitter, the PCC MUST be able to apply additional constraints to the request. The format of the Wavelength Restriction Constraint TLV is as follows: Lee & Casellas Expires February 15,2017 [Page 8] Internet-Draft PCEP Extension for WSON RWA August 2016 ::= ( )... Where ::= [] See Section 4.2.1. for the encoding of the Link Identifiers Field. The Wavelength Restriction Constraint TLV type is TBD, recommended value is TBD. This TLV MAY appear more than once to be able to specify multiple restrictions. The TLV data is defined as follows: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Action | Count | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link Identifiers | | . . . | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Wavelength Restriction Field | // . . . . // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4 Wavelength Restriction Constraint TLV Encoding o Action: 8 bits . 0 - Inclusive List indicates that one or more link identifiers are included in the Link Set. Each identifies a separate link that is part of the set. Lee & Casellas Expires February 15,2017 [Page 9] Internet-Draft PCEP Extension for WSON RWA August 2016 . 1 - Inclusive Range indicates that the Link Set defines a range of links. It contains two link identifiers. The first identifier indicates the start of the range (inclusive). The second identifier indicates the end of the range (inclusive). All links with numeric values between the bounds are considered to be part of the set. A value of zero in either position indicates that there is no bound on the corresponding portion of the range. Note that the Action field can be set to 0 when unnumbered link identifier is used. Note that "interfaces" such as those discussed in the Interfaces MIB [RFC2863] are assumed to be bidirectional. o Count: The number of the link identifiers (8 bits) Note that a PCC MAY add a Wavelength restriction that applies to all links by setting the Count field to zero and specifying just a set of wavelengths. Note that all link identifiers in the same list must be of the same type. o Reserved: Reserved for future use (16 bits) o Link Identifiers: Identifies each link ID for which restriction is applied. The length is dependent on the link format and the Count field. See Section 4.2.1. for Link Identifier encoding and Section 4.2.2. for the Wavelength Restriction Field encoding, respectively. 4.3.1. Link Identifier Field The link identifier field can be an IPv4, IPv6 or unnumbered interface ID. ::= | | The encoding of each case is as follows: Lee & Casellas Expires February 15,2017 [Page 10] Internet-Draft PCEP Extension for WSON RWA August 2016 IPv4 prefix Entry 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 1 | IPv4 address (4 bytes) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 address (continued) | Prefix Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IPv6 prefix Sub-TLV 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 2 | IPv6 address (16 bytes) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 address (continued) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 address (continued) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 address (continued) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv6 address (continued) | Prefix Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Unnumbered Interface ID Sub-TLV 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type = 3 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TE Node ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Interface ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Lee & Casellas Expires February 15,2017 [Page 11] Internet-Draft PCEP Extension for WSON RWA August 2016 4.3.2. Wavelength Restriction Field The Wavelength Restriction Field of the wavelength restriction TLV is encoded as a Label Set field as specified in [RFC7579] section 2.6, as shown below, with base label encoded as a 32 bit LSC label, defined in [RFC6205]. See [RFC6205] for a description of Grid, C.S, Identifier and n, as well as [RFC7579] for the details of each action. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Action| Num Labels | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Grid | C.S | Identifier | n | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Additional fields as necessary per action | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Action: 0 - Inclusive List 1 - Exclusive List 2 - Inclusive Range 3 - Exclusive Range 4 - Bitmap Set Num Labels is generally the number of labels. It has a specific meaning depending on the action value. Num Labels is a 12 bit integer. Length is the length in bytes of the entire label set field. See Sections 2.6.1 - 2.6.3 of [RFC7579] for details on additional field discussion for each action. Lee & Casellas Expires February 15,2017 [Page 12] Internet-Draft PCEP Extension for WSON RWA August 2016 4.4. Signal processing capability restrictions Path computation for WSON include the check of signal processing capabilities, those capability MAY be provided by the IGP, however this is not a MUST. Moreover, a PCC should be able to indicate additional restrictions for those signal compatibility, either on the endpoint or any given link. The supported signal processing capabilities are the one described in [RFC7446]: . Optical Interface Class List . Bit Rate . Client Signal The Bit Rate restriction is already expressed in [PCEP-GMPLS] in the BANDWIDTH object. In order to support the Optical Interface Class information and the Client Signal information new TLVs are introduced as endpoint- restriction in the END-POINTS type Generalized endpoint: . Client Signal TLV . Optical Interface Class List TLV The END-POINTS type generalized endpoint is extended as follows: ::= [...] Where signal-compatibility-restriction ::= Lee & Casellas Expires February 15,2017 [Page 13] Internet-Draft PCEP Extension for WSON RWA August 2016 The encoding for the Optical Interface Class List is described in Section 4.1 of [RFC7581]. The encoding for the Client Signal Information is described in Section 4.2 of [RFC7581]. 4.4.1. Signal Processing Exclusion XRO Sub-Object The PCC/PCE should be able to exclude particular types of signal processing along the path in order to handle client restriction or multi-domain path computation. In order to support the exclusion a new XRO sub-object is defined: the signal processing exclusion: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |X| Type = X | Length | Reserved | Attribute | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | sub-sub objects | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5 Signaling Processing XRO Sub-Object The Attribute field indicates how the exclusion sub-object is to be interpreted. The Attribute can only be 0 (Interface) or 1 (Node). The sub-sub objects are encoded as in RSVP signaling definition [RFC7689]. 4.4.2. IRO sub-object: signal processing inclusion Similar to the XRO sub-object the PCC/PCE should be able to include particular types of signal processing along the path in order to handle client restriction or multi-domain path computation. This is supported by adding the sub-object ''processing'' defined for ERO in [RFC7689] to the PCEP IRO object. Lee & Casellas Expires February 15,2017 [Page 14] Internet-Draft PCEP Extension for WSON RWA August 2016 5. Encoding of a RWA Path Reply This section provides the encoding of a RWA Path Reply for wavelength allocation as discussed in Section 4. Recall that wavelength allocation can be performed by the PCE by different means: (a) By means of Explicit Label Control (ELC) where the PCE allocates which label to use for each interface/node along the path. (b) By means of a Label Set where the PCE provides a range of potential labels to allocate by each node along the path. Option (b) allows distributed label allocation (performed during signaling) to complete wavelength allocation. The Wavelength Allocation TLV type is TBD, recommended value is TBD. The TLV data is defined as follows: 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved |M| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link Identifier | | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Allocated Wavelength(s) | // . . . . // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 6 Wavelength Allocation TLV Encoding o Reserved: Reserved for future use (31 bits) o M (Mode): 1 bit . 0 - - indicates the allocation is under Explicit Label Control. . 1 - - indicates the allocation is expressed in Label Sets. Lee & Casellas Expires February 15,2017 [Page 15] Internet-Draft PCEP Extension for WSON RWA August 2016 Note that all link identifiers in the same list must be of the same type. o Link Identifier (variable): Identifies the interface to which assignment wavelength(s) is applied. See Section 4.2.1. for Link Identifier encoding. o Assigned Wavelength(s) (variable): Indicates the assigned wavelength(s) to the link identifier. See Section 4.2.2 for encoding details. This TLV is encoded as an attributes TLV, per [RFC5420], which is carried in the ERO LSP Attribute Subobjects per [RSVP-RO]. The type value of the Wavelength Restriction Constraint TLV is TBD by IANA. 5.1. Error Indicator To indicate errors associated with the RWA request, a new Error Type (TDB) and subsequent error-values are defined as follows for inclusion in the PCEP-ERROR Object: A new Error-Type (TDB) and subsequent error-values are defined as follows: . Error-Type=TBD; Error-value=1: if a PCE receives a RWA request and the PCE is not capable of processing the request due to insufficient memory, the PCE MUST send a PCErr message with a PCEP-ERROR Object (Error-Type=TDB) and an Error-value(Error- value=1). The PCE stops processing the request. The corresponding RWA request MUST be cancelled at the PCC. . Error-Type=TBD; Error-value=2: if a PCE receives a RWA request and the PCE is not capable of RWA computation, the PCE MUST send a PCErr message with a PCEP-ERROR Object (Error-Type=TDB) and an Error-value (Error-value=2). The PCE stops processing the request. The corresponding RWA computation MUST be cancelled at the PCC. Lee & Casellas Expires February 15,2017 [Page 16] Internet-Draft PCEP Extension for WSON RWA August 2016 5.2. NO-PATH Indicator To communicate the reason(s) for not being able to find RWA for the path request, the NO-PATH object can be used in the corresponding response. The format of the NO-PATH object body is defined in [RFC5440]. The object may contain a NO-PATH-VECTOR TLV to provide additional information about why a path computation has failed. One new bit flag are defined to be carried in the Flags field in the NO-PATH-VECTOR TLV carried in the NO-PATH Object. . Bit TDB: When set, the PCE indicates no feasible route was found that meets all the constraints (e.g., wavelength restriction, signal compatibility, etc.) associated with RWA. 6. Manageability Considerations Manageability of WSON Routing and Wavelength Assignment (RWA) with PCE must address the following considerations: 6.1. Control of Function and Policy In addition to the parameters already listed in Section 8.1 of [PCEP], a PCEP implementation SHOULD allow configuring the following PCEP session parameters on a PCC: . The ability to send a WSON RWA request. In addition to the parameters already listed in Section 8.1 of [PCEP], a PCEP implementation SHOULD allow configuring the following PCEP session parameters on a PCE: . The support for WSON RWA. . A set of WSON RWA specific policies (authorized sender, request rate limiter, etc). These parameters may be configured as default parameters for any PCEP session the PCEP speaker participates in, or may apply to a specific session with a given PCEP peer or a specific group of sessions with a specific group of PCEP peers. Lee & Casellas Expires February 15,2017 [Page 17] Internet-Draft PCEP Extension for WSON RWA August 2016 6.2. Information and Data Models, e.g. MIB module Extensions to the PCEP MIB module defined in [PCEP-MIB] should be defined, so as to cover the WSON RWA information introduced in this document. A future revision of this document will list the information that should be added to the MIB module. 6.3. Liveness Detection and Monitoring Mechanisms defined in this document do not imply any new liveness detection and monitoring requirements in addition to those already listed in section 8.3 of [RFC5440]. 6.4. Verifying Correct Operation Mechanisms defined in this document do not imply any new verification requirements in addition to those already listed in section 8.4 of [RFC5440] 6.5. Requirements on Other Protocols and Functional Components The PCE Discovery mechanisms ([RFC5089] and [RFC5088]) may be used to advertise WSON RWA path computation capabilities to PCCs. 6.6. Impact on Network Operation Mechanisms defined in this document do not imply any new network operation requirements in addition to those already listed in section 8.6 of [RFC5440]. 7. Security Considerations This document has no requirement for a change to the security models within PCEP [PCEP]. However the additional information distributed in order to address the RWA problem represents a disclosure of network capabilities that an operator may wish to keep private. Consideration should be given to securing this information. Lee & Casellas Expires February 15,2017 [Page 18] Internet-Draft PCEP Extension for WSON RWA August 2016 8. IANA Considerations IANA maintains a registry of PCEP parameters. IANA has made allocations from the sub-registries as described in the following sections. 8.1. New PCEP Object As described in Section 4.1, a new PCEP Object is defined to carry wavelength assignment related constraints. IANA is to allocate the following from ''PCEP Objects'' sub-registry (http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-objects): Object Class Name Object Reference Value Type --------------------------------------------------------- TDB WA 1: Wavelength-Assignment [This.I-D] 8.2. New PCEP TLV: Wavelength Selection TLV As described in Sections 4.2, a new PCEP TLV is defined to indicate wavelength selection constraints. IANA is to allocate this new TLV from the "PCEP TLV Type Indicators" subregistry (http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type- indicators). Value Description Reference --------------------------------------------------------- TBD Wavelength Selection [This.I-D] 8.3. New PCEP TLV: Wavelength Restriction Constraint TLV As described in Sections 4.3, a new PCEP TLV is defined to indicate wavelength restriction constraints. IANA is to allocate this new TLV from the "PCEP TLV Type Indicators" subregistry Lee & Casellas Expires February 15,2017 [Page 19] Internet-Draft PCEP Extension for WSON RWA August 2016 (http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type- indicators). Value Description Reference --------------------------------------------------------- TBD Wavelength Restriction [This.I-D] Constraint 8.4. New PCEP TLV: Wavelength Allocation TLV As described in Section 5, a new PCEP TLV is defined to indicate the allocation of wavelength(s) by the PCE in response to a request by the PCC. IANA is to allocate this new TLV from the "PCEP TLV Type Indicators" subregistry (http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type- indicators). Value Description Reference --------------------------------------------------------- TBD Wavelength Allocation [This.I-D] 8.5. New PCEP TLV: Optical Interface Class List TLV As described in Section 4.3, a new PCEP TLV is defined to indicate the optical interface class list. IANA is to allocate this new TLV from the "PCEP TLV Type Indicators" subregistry (http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type- indicators). Value Description Reference --------------------------------------------------------- TBD Optical Interface [This.I-D] Class List 8.6. New PCEP TLV: Client Signal TLV As described in Section 4.3, a new PCEP TLV is defined to indicate the client signal information. IANA is to allocate this new TLV from Lee & Casellas Expires February 15,2017 [Page 20] Internet-Draft PCEP Extension for WSON RWA August 2016 the "PCEP TLV Type Indicators" subregistry (http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-tlv-type- indicators). Value Description Reference --------------------------------------------------------- TBD Client Signal Information [This.I-D] 8.7. New No-Path Reasons As described in Section 5.2., a new bit flag are defined to be carried in the Flags field in the NO-PATH-VECTOR TLV carried in the NO-PATH Object. This flag, when set, indicates that no feasible route was found that meets all the RWA constraints (e.g., wavelength restriction, signal compatibility, etc.) associated with a RWA path computation request. IANA is to allocate this new bit flag from the "PCEP NO-PATH-VECTOR TLV Flag Field" subregistry (http://www.iana.org/assignments/pcep/pcep.xhtml#no-path-vector- tlv). Bit Description Reference ----------------------------------------------------- TBD No RWA constraints met [This.I-D] 8.8. New Error-Types and Error-Values As described in Section 5.1, new PCEP error codes are defined for WSON RWA errors. IANA is to allocate from the ''"PCEP-ERROR Object Error Types and Values" sub-registry (http://www.iana.org/assignments/pcep/pcep.xhtml#pcep-error-object). Error- Meaning Error-Value Reference Type --------------------------------------------------------------- TDB WSON RWA Error 1: Insufficient [This.I-D] Lee & Casellas Expires February 15,2017 [Page 21] Internet-Draft PCEP Extension for WSON RWA August 2016 Memory 2: RWA computation {This.I-D] Not supported 9. Acknowledgments The authors would like to thank Adrian Farrel for many helpful comments that greatly improved the contents of this draft. This document was prepared using 2-Word-v2.0.template.dot. 10. References 10.1. Informative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description", RFC 3471, January 2003. [RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol- Traffic Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. [RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links in Resource ReSerVation Protocol - Traffic Engineering (RSVP-TE)", RFC 3477, January 2003. [RFC4003] Berger, L., "GMPLS Signaling Procedure for Egress Control", RFC 4003, February 2005. [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation Element (PCE)-Based Architecture", RFC 4655, August 2006. [RFC4657] Ash, J. and J. Le Roux, "Path Computation Element (PCE) Communication Protocol Generic Requirements", RFC 4657, September 2006. Lee & Casellas Expires February 15,2017 [Page 22] Internet-Draft PCEP Extension for WSON RWA August 2016 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation Element (PCE) communication Protocol", RFC 5440, March 2009. 10.2. Normative References [PCEP-GMPLS] Margaria, et al., ''PCEP extensions for GMPLS'', draft- ietf-pce-gmpls-pcep-extensions, work in progress. [RFC7570] Margaria, et al., ''Label Switched Path (LSP) Attribute in the Explicit Route Object (ERO)'', RFC 7570, July 2015. [PCEP-Layer] Oki, Takeda, Le Roux, and Farrel, ''Extensions to the Path Computation Element communication Protocol (PCEP) for Inter-Layer MPLS and GMPLS Traffic Engineering'', draft- ietf-pce-inter-layer-ext, work in progress. [RFC6163] Lee, Y. and Bernstein, G. (Editors), and W. Imajuku, "Framework for GMPLS and PCE Control of Wavelength Switched Optical Networks", RFC 6163, March 2011. [RFC7449] Lee, Y., et. al., "PCEP Requirements for WSON Routing and Wavelength Assignment", RFC 7449, February 2015. [RFC6205] Tomohiro, O. and D. Li, "Generalized Labels for Lambda- Switching Capable Label Switching Routers", RFC 6205, January, 2011. [RFC7689] Bernstein et al, ''Signaling Extensions for Wavelength Switched Optical Networks'', RFC 7689, November 2015. [RFC7688] Y. Lee, and G. Bernstein, ''OSPF Enhancement for Signal and Network Element Compatibility for Wavelength Switched Optical Networks'', RFC 7688, November 2015. [RFC7446] Y. Lee, G. Bernstein. (Editors), ''Routing and Wavelength Assignment Information Model for Wavelength Switched Optical Networks'', RFC 7446, February 2015. [RFC7581] Bernstein and Lee, ''Routing and Wavelength Assignment Information Encoding for Wavelength Switched Optical Networks'', RFC7581, June 2015. [RFC7579] Bernstein and Lee, ''General Network Element Constraint Encoding for GMPLS Controlled Networks'', RFC 7579, June 2015. Lee & Casellas Expires February 15,2017 [Page 23] Internet-Draft PCEP Extension for WSON RWA August 2016 [WSON-Imp] Y. Lee, G. Bernstein, D. Li, G. Martinelli, "A Framework for the Control of Wavelength Switched Optical Networks (WSON) with Impairments", draft-ietf-ccamp-wson- impairments, work in progress. [RSVP-Imp] agraz, ''RSVP-TE Extensions in Support of Impairment Aware Routing and Wavelength Assignment in Wavelength Switched Optical Networks WSONs)'', draft-agraz-ccamp-wson- impairment-rsvp, work in progress. [OSPF-Imp] Bellagamba, et al., ''OSPF Extensions for Wavelength Switched Optical Networks (WSON) with Impairments'',draft- eb-ccamp-ospf-wson-impairments, work in progress. 11. Contributors Lee & Casellas Expires February 15,2017 [Page 24] Internet-Draft PCEP Extension for WSON RWA August 2016 Authors' Addresses Young Lee, Editor Huawei Technologies 1700 Alma Drive, Suite 100 Plano, TX 75075, USA Phone: (972) 509-5599 (x2240) Email: leeyoung@huawei.com Ramon Casellas, Editor CTTC PMT Ed B4 Av. Carl Friedrich Gauss 7 08860 Castelldefels (Barcelona) Spain Phone: (34) 936452916 Email: ramon.casellas@cttc.es Fatai Zhang Huawei Technologies Email: zhangfatai@huawei.com Cyril Margaria Nokia Siemens Networks St Martin Strasse 76 Munich, 81541 Germany Phone: +49 89 5159 16934 Email: cyril.margaria@nsn.com Oscar Gonzalez de Dios Telefonica Investigacion y Desarrollo C/ Emilio Vargas 6 Madrid, 28043 Spain Phone: +34 91 3374013 Email: ogondio@tid.es Greg Bernstein Grotto Networking Fremont, CA, USA Phone: (510) 573-2237 Email: gregb@grotto-networking.com Lee & Casellas Expires February 15,2017 [Page 25]