Internet Engineering Task Force G. Martinelli, Ed. Internet-Draft Cisco Systems Intended status: Standards Track A. Zanardi, Ed. Expires: January 14, 2010 CREATE-NET July 13, 2009 GMPLS Signaling Extensions for Optical Impairment Aware Lightpath Setup draft-martinelli-ccamp-optical-imp-signaling-02.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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on January 14, 2010. Copyright Notice Copyright (c) 2009 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 in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Abstract The problem of provisioning a lightpath in a transparent dense wavelength division multiplexing (DWDM) optical island requires the Martinelli & Zanardi Expires January 14, 2010 [Page 1] Internet-Draft Optical Impairment Signaling July 2009 evaluation of of the optical impairments along the selected route. In this memo we propose a GMPLS signaling protocol (RSVP/RSVP-TE) extension to collect and provide the egress node the optical impairment parameters needed to validate a lightpath setup request feasibility. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions Used in This Document . . . . . . . . . . . . . . 3 3. Optical Path Impairment Validation . . . . . . . . . . . . . . 3 3.1. Procedure for Distributed Validation . . . . . . . . . . . 4 3.2. The Wavelenght Assignment Problem . . . . . . . . . . . . 5 4. Optical Parameters Classification . . . . . . . . . . . . . . 5 5. Information Encoding . . . . . . . . . . . . . . . . . . . . . 6 6. Optical Service Parameters sub-TLV . . . . . . . . . . . . . . 8 6.1. Forward Error Correction (FEC) . . . . . . . . . . . . . . 9 6.2. Modulation Format . . . . . . . . . . . . . . . . . . . . 9 7. Optical Path Parameters sub-TLV(s) . . . . . . . . . . . . . . 10 7.1. Optical Parameter sub-TLV overview . . . . . . . . . . . . 11 7.2. Mandatory Linear Optical Parameters sub-TLVs . . . . . . . 11 7.2.1. Optical Power . . . . . . . . . . . . . . . . . . . . 11 7.2.2. Optical Signal to Noise Ratio . . . . . . . . . . . . 12 7.3. Optional Linear Optical Parameters sub-TLVs . . . . . . . 12 7.3.1. Chromatic Dispersion (CD) . . . . . . . . . . . . . . 12 7.3.2. Polarization Mode Dispersion (PMD) . . . . . . . . . . 12 7.3.3. Cross-Talk (XT) . . . . . . . . . . . . . . . . . . . 12 8. Message Fragmentation . . . . . . . . . . . . . . . . . . . . 12 9. Backward Compatibility . . . . . . . . . . . . . . . . . . . . 15 10. Error management . . . . . . . . . . . . . . . . . . . . . . . 15 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15 12. Contributing Authors . . . . . . . . . . . . . . . . . . . . . 15 13. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 14. Security Considerations . . . . . . . . . . . . . . . . . . . 17 15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17 15.1. Normative References . . . . . . . . . . . . . . . . . . . 17 15.2. Informative References . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19 Martinelli & Zanardi Expires January 14, 2010 [Page 2] Internet-Draft Optical Impairment Signaling July 2009 1. Introduction The current Generalized Multi-Protocol Label Switching (GMPLS) specification [RFC3945] and the signaling related documents ([RFC3471], [RFC3473], [RFC4328]) support optical interfaces with different switching capability. With the definition of Wavelength Switched Optical Networks (WSON) the framework document [I-D.ietf-ccamp-rwa-wson-framework] provides the basic information and addresses the routing wavelength assignment problem. Signaling extension related to WSON are detailed in [I-D.bernstein-ccamp-wson-signaling]. The implementation technology for the WSON is the Dense Wavelength Division Multiplexing (DWDM)and one of the key issue is the physical impairments incurred by non-ideal optical transmission medium that accumulate along an optical path. This topic is considered out of scope for the above WSON documents while is detailed in framework [I-D.ietf-ccamp-wson-impairments]. The framework provides the motivation why optical impairments are important and provides an overview of the control plane architectural options. It also references ITU-T standards where optical networks and their parameters are defined. For a successful lightpath provisioning in a WSON, the set up process must be aware of a set of physical impairments that has effect on the lightpath. This memo proposes extensions to signaling protocol (RSVP/RSVP-TE) as a way to collect and verify some basic optical impairments in order to get a successful lightpath setup. The solution implements what the [I-D.ietf-ccamp-wson-impairments] defines as distributed validation process. The management of optical impairments is done only in the signaling process and it does not require any extension to the traffic engineering database and routing protocols or Path Computational Element (PCE). 2. Conventions Used in This Document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. In additions this document will use terminology from [RFC2205], [RFC3209], [RFC4054], and [I-D.ietf-ccamp-rwa-wson-framework]. 3. Optical Path Impairment Validation Martinelli & Zanardi Expires January 14, 2010 [Page 3] Internet-Draft Optical Impairment Signaling July 2009 3.1. Procedure for Distributed Validation The signaling based validation of an optical path in downstream direction in a transparent network (lambda switched LSP) is implemented by the following procedure: o The ingress node signals in the Path message the supported signal types (Forward Error Correction and modulation format) and wavelength set (encoded in the LABEL_SET Object) depending on available local transponders. o Transit nodes update the Path message pruning non cross- connectable wavelengths (LABEL_SET Object) and computing or measuring the path optical characteristics up to the outgoing interface (optical impairments). o The egress node selects the wavelength and the signal type based on the signaled optical impairments and the available local transponders (supported wavelengths, sensitivity to optical impairments) and signals the selection in the Resv message. o Transit nodes process the Resv message cross-connecting the selected wavelength in incoming and outgoing interfaces (wavelength continuity constraint). o The ingress node cross-connects the selected wavelength to a local transponder supporting the selected signal type (Forward Error Correction and modulation format). This procedure forces the meeting of the wavelength continuity constraint: the final effect of pruning wavelengths (e.g. removing labels from the LABEL_SET object) in transit nodes is the implementation of a wavelength selection process in the signaling phase. The wavelength assignment will be done at the egress node among all available wavelength for the LSP. The criteria used by the egress node to assign the wavelength is out of the scope of this document. In the Path message processing, the unavailability of cross- connectable wavelength in transit nodes or of transponders supporting the signal in the egress node causes the request failure (PathErr message). In the Resv message processing, the unavailability of the selected wavelength in transit nodes or of transponders supporting the signal in the ingress node (race condition in allocating resources) causes the request failure (ResvErr message). Martinelli & Zanardi Expires January 14, 2010 [Page 4] Internet-Draft Optical Impairment Signaling July 2009 In this document, only the encoding in the RSVP messages of the optical information needed to support the described procedure is defined. The specific policies used to select the resources (wavelength and transponders), the models to compute the optical impairments and the procedure to validate the signal with respect to the transponder sensitivity are not in the scope of this document. 3.2. The Wavelenght Assignment Problem The impairment framework document [I-D.ietf-ccamp-wson-impairments] details how the Routing and Wavelength Assignment (RWA) function and the Impairment Validation (IV) function can be combined withing different architectural options. The distributed IV as detailed in this memo is compatible with different options for implementing the WA function. In case the WA function is implemented elsewhere the procedure above still apply apart from considering a single wavelength instead of a wavelength set. If optical validation fail along the path, instead of pruning a wavelet, the node will reply directly with a PathErr and the Lightpath setup will fail. 4. Optical Parameters Classification The set of optical parameters carried by the signaling protocol is divided into optical service parameters and optical path parameters. The actual list is defined elsewhere like [ITU.G680] and [I-D.bernstein-wson-impairment-info]. Scope of this section is just to propose a classification appropriate for RSVP-TE encoding. o Optical Service Parameters. For DWDM networks the egress node of an LSP has to know a certain set of specific optical parameters related to the transmitting interface. The optical service parameters describe the requested signal type and are related to the characteristics of the transponder at ingress node. They MUST NOT change at transit nodes. Section 6 details of parameters and their encoding. In the standard signaling, GENERALIZED_LABEL_REQUEST and TSPEC/ FLOW_SPEC objects support the encoding of equivalent information like the service type and service QoS. In the context of WSON also the draft [I-D.bernstein-ccamp-wson-signaling] reports some of this parameters. o Optical Path Parameters. The optical path parameters describe the signal characteristics Martinelli & Zanardi Expires January 14, 2010 [Page 5] Internet-Draft Optical Impairment Signaling July 2009 evolution along the path from ingress node to egress node, are related to the characteristics of the various links/subsystems and are updated at each transit node. They are divided into mandatory and optional parameters. The mandatory parameters are related to feasibility constraints such as power and OSNR, whereas the optional parameters are expandable linear impairments such as chromatic dispersion (CD), polarization mode dispersion (PMD), crosstalk, etc. The optional parameters can be used to evaluate the feasibility of a lightpath more accurately as an alternate solution to the bounded OSNR margin evaluation. Parameter update methods might use appropriate physical models and are out of scope of this document. The [I-D.bernstein-wson-impairment-info] identifies which are the parameters and the related ITU-T source document. Section 7 shows RSVP-TE encoding details. 5. Information Encoding This document defines how to encode the above information through new TLVs according to [RFC5420]. The proposed encoding scheme for the optical parameters defines a TLV (channel optical physical information) associated to a wavelength containing a sub-TLV for each service and path parameter. Additional set of parameters can be added without affecting the already defined encoding. A TLV sub-object for each available wavelength (Path message) or selected wavelength (Resv message) is encoded in an LSP_REQUIRED_ATTRIBUTES Object. The TLV sub-object encoding is defined in the next picture. Martinelli & Zanardi Expires January 14, 2010 [Page 6] Internet-Draft Optical Impairment Signaling July 2009 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 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Wavelength ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // Parameters Sub-TLV Sequence // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 o Type: optical channel physical parameters info TLV type (TBA). o Length: total length of the TLV including header in octets. o Wavelength ID: wavelength label identifier according to [I-D.ietf-ccamp-gmpls-g-694-lambda-labels]. o Parameters Sub-TLV Sequence: service and path parameters values. The TLVs wavelength ID value must be consistent with the presence of LABEL_SET objects and its actions as defined within [RFC3471] and [RFC3473]. The Sub-TLV format is defined in the next picture 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 | Flags | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | // Value // | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2 Type: Sub-TLV type Flags: bit-mask defining the management of the Sub-TLV bit 0: if set the parameter is mandatory, otherwise it is optional. Martinelli & Zanardi Expires January 14, 2010 [Page 7] Internet-Draft Optical Impairment Signaling July 2009 bit 1: if set the parameter is variable and MUST be updated with the local value, otherwise it is a constant value set by the ingress node. bit 2-7: not used. Length: total length of the sub-TLV including header in octects. Value: variable length Sub-TLV content The Flags field defines how transit nodes manage the Sub-TLV: o Constant sub-TLVs are forwarded as-is. o Mandatory non constant sub-TLVs MUST be updated with the local parameter value, if the parameter is not managed by the node, it MUST reject the request with a failure. o Optional non constant sub-TLVs MUST be updated with the local parameter value, if the parameter is not managed by the node, it MUST silently drop it from the TLV (the value would be inaccurate). 6. Optical Service Parameters sub-TLV The Optical Service Parameters define the signal transmissions characteristics at the ingress node. This type of information is required at the egress node to verify the optical signal compatibility. 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 | Flags | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FEC 1 | Mod Format 1 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ // // +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | FEC n | Mod Format n | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3 Martinelli & Zanardi Expires January 14, 2010 [Page 8] Internet-Draft Optical Impairment Signaling July 2009 Type: sub-TLV type (=1) Flags: Mandatory, Constant Length: total length of the sub-TLV including header in octets FEC: supported Forward Error Correction Modes (see Section 6.1 Mod Format: supported modulation formats (see Section 6.2) associated with the FEC. This sub-TLV is used in the PATH message to signal the full list of optical parameters associated with the interface (signal types and wavelengths) available at the ingress node. A DWDM interface might have several sets of optical parameters available, for example a tunable interface has a set of possible wavelengths, together with a set of possible FEC encoding or modulation formats. In the RESV message this information is associated to the selected receiving interface at the egress node. In the RESV message only one tuple (FEC, Mod Format) will be specified. 6.1. Forward Error Correction (FEC) FEC (16 bits) field is the Forward Error Correction and has the following values: 0: no FEC 1: standard FEC (according to [ITU.G709]) 2-9: super-FEC according to sub clauses from I.2 to I.9 of [ITU.G975.1] Values with the format 1bbbbbbbbbbbbbbb are left to represent vendor specific or proprietary FEC encoding. 6.2. Modulation Format Editorial Node: this encoding section need to be reviewed with [I-D.bernstein-ccamp-wson-signaling]. Mod Format (16 bits) is the modulation and has the following values: 0: NRZ 1: Duo Binary Martinelli & Zanardi Expires January 14, 2010 [Page 9] Internet-Draft Optical Impairment Signaling July 2009 2: DPSK Other values might be defined in the future as technology advance. Values with the format 1bbbbbbbbbbbbbbb are left to represent vendor specific or proprietary modulation formats. 7. Optical Path Parameters sub-TLV(s) This set of parameters is carried in the PATH message for each available wavelength to allow the optical feasibility evaluation. At each hop, the optical node MUST update these values according to information locally available at the node (say internal amplifiers, wavelength cross connect, etc.). This sub-TLV implements the Distributed Impairment evaluation as per [I-D.bernstein-wson-impairment-info] The way an optical node gets knowledge of this required information (e.g. through network management system, auto-discovery etc.) is out of the scope of this document and highly depends on specific equipment implementation. This document defines two groups of linear optical parameters. Mandatory Linear Optical Parameters This set includes Optical Signal Power and the OSNR with associated variances. It represents the minimum set to asses the feasibility of an optical path. This set will be encoded using mandatory sub-TLVs. Optional Linear Optical Parameters This set includes CD, PMD, XT with associated variances. These parameters represent an additional set to allow a more accurate optical feasibility evaluation. This set will be encoded using optional sub-TLVs. Separation between mandatory and optional parameters allows a rough optical feasibility evaluation where network elements support at least the mandatory set. Depending on how a WSON is designed, the usage of the mandatory set could be an operational choice not to overwhelm the control plane while maintaining reliable feasibility estimation. Moreover it might happens that not all nodes in a networks support the full set of optical path parameters. With this classification, the lightpath signaling still continues to work although with a less accurate evaluation. The choice of the optional set of parameters depends on several considerations. They are among those reported by the [RFC4054] and Martinelli & Zanardi Expires January 14, 2010 [Page 10] Internet-Draft Optical Impairment Signaling July 2009 provide sufficient accuracy for the linear impairments evaluation. 7.1. Optical Parameter sub-TLV overview Each optical parameter will be encoded using the following format: 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 | Flags | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Optical Parameter Value | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Optical Parameter Variance | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4 Type: sub_TLV type > 1. Flags: mandatory or optional according to each parameter classification, variable. Length: total length of the Sub-TLV including header in octets (8 octets or 12 octets depending if the optical parameter has the variance value associated). Value associated with the optical parameter. Variance: the error estimation for optical parameter value calculation. Depending on the length value may not be present. 7.2. Mandatory Linear Optical Parameters sub-TLVs The Sub-TLVs encode the following optical parameters of a channel (wavelength) measured at the node egress interface. Flags are: mandatory, variable. 7.2.1. Optical Power Type = 2. Value: 32bit IEEE floating point number. Measurement Unit: dBm. Martinelli & Zanardi Expires January 14, 2010 [Page 11] Internet-Draft Optical Impairment Signaling July 2009 7.2.2. Optical Signal to Noise Ratio Type = 3. Value: 32bit IEEE floating point number. Measurement Unit: dB. 7.3. Optional Linear Optical Parameters sub-TLVs The Sub-TLVs encode the following optical parameters of a channel (wavelength) measured at the node egress interface. Flags are: optional, variable. 7.3.1. Chromatic Dispersion (CD) Type = 4. Value: 32bit IEEE floating point number. Measurement Unit: ps/nm. 7.3.2. Polarization Mode Dispersion (PMD) Type = 5. Value: 32bit IEEE floating point number. Measurement Unit: ps. 7.3.3. Cross-Talk (XT) Type = 6. Value: 32bit IEEE floating point number. Measurement Unit: dB. 8. Message Fragmentation In certain cases, the state information carried by the Path message can be quite large. Size estimation for a physical Optical Channel TLV (see Figure 1) can be the following: 8 bytes for type, length and wavelength ID plus, 16 bytes for the Optical Service Parameters sub- TLV considering 3 FEC/modulation format combinations plus, 24 bytes for the Mandatory Linear Optical Path parameters plus 36 bytes for the Optional Linear Optical Parameter sub-TLV. Total is 48 bytes for each wavelength by just considering mandatory sub-TLVs and 84 bytes by considering also the optional part. Given the number of wavelengths today available in DWDM networks, the size of the path message end up in large values. For example to signal just 32 wavelengths the size required for the physical optical parameters ranges at least from 1536 to 2688 bytes. A possible option is to let the application layer requesting the Martinelli & Zanardi Expires January 14, 2010 [Page 12] Internet-Draft Optical Impairment Signaling July 2009 lightpath setup to decide how many wavelengths to signal according to the MTU available. For example, having an MTU of 1500 bytes the application layer might signal only 10 wavelengths with the full set of parameters taking up 840 bytes, or it might decide to signal 20 wavelengths with just the mandatory parameters. Note that, according to procedure described within Section 3, the message size may decrease as long as the Path message pass through transit nodes. A second solution proposed here implements the semantic fragmentation as suggested by RSVP [RFC2205]. The proposed encoding extends the SENDER_TEMPLATE Object with a new Class Type (derived from the LSP_TUNNEL_IPv4 and LSP_TUNNEL_IPv6 RSVP-TE [RFC3209]). The Object includes the additional information on the "fragment id" and on the requested policy for the channel selection at the egress node Class = SENDER_TEMPLATE, FRAGREQ_LSP_TUNNEL_IPv4 C-Type = TBA 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | IPv4 tunnel sender address | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | LSP ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TotalNo | MsgId | P | Timeout | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5 Martinelli & Zanardi Expires January 14, 2010 [Page 13] Internet-Draft Optical Impairment Signaling July 2009 Class = SENDER_TEMPLATE, FRAGREQ_LSP_TUNNEL_IPv6 C-Type = TBA 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + + | IPv6 tunnel sender address | + + | (16 bytes) | + + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | LSP ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | TotalNo | MsgId | P | Timeout | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 6 Besides the fields already defined in the SENDER_TEMPLATE, the following fields are defined: o TotalNo: 8 bit integer representing the total number of Path messages issued by the ingress node to setup a single lightpath. When this values is equals to 1 all the other fields MUST be ignored. o MsgId: 8 bit integer representing the sequential number of a single Path request. Its value must be between 1 and TotalNo, both inclusive. o P: Policy the egress node must apply upon receiving a fragmented path request: 1: Take the first message arrived and ignore the following ones. 2: After the first message arrives, wait for any message within the specified Timeout. 3: After the first message arrives, waits for all messages. Fail, if the timeout expires, and there's at least one message missing The egress node should "reject" (PathErr) all the requests except for the selected one, even if it could rely on the RSVP timeout to clear the unselected requests status in upstream nodes. Martinelli & Zanardi Expires January 14, 2010 [Page 14] Internet-Draft Optical Impairment Signaling July 2009 o Timeout: 12 bits integer number representing the timeout value used by the policy. The value is in s/100 (hundreds of seconds) All messages MUST have the same value. This type of encoding is a generic solution to manage the semantic fragmentation and its not strictly related to optical parameters encoding. 9. Backward Compatibility The TLV usage as defined by [RFC5420] will guarantee the co-existence of nodes supporting normal RSVP-TE operations and node with optical impairment signaling capability. A service with the new feature (optical feasibility evaluation) can be setup only if all the nodes in the path support the extensions. Optical Path Parameters are updated hop-by-hop and evaluated at egress node. If a transit node does not support the extensions the collected information is unreliable and the Path request MUST be rejected. 10. Error management No additional error code is introduced to manage requests failures; the behavior defined in [RFC5420] applies to the management of the LSP_REQUIRED_ATTRIBUTES Object. 11. Acknowledgments 12. Contributing Authors This document was the collective work of several authors. The text and content of this document was contributed by the editors and the co-authors listed below (the contact information for the editors appears in appropriate section and is not repeated below): Martinelli & Zanardi Expires January 14, 2010 [Page 15] Internet-Draft Optical Impairment Signaling July 2009 Gabriele Maria Galimberti Cisco Systems via Philips 12 Monza 20052, Italy Email: ggalimbe@cisco.com Alberto Tanzi Cisco Systems via Philips 12 Monza 20052, Italy Email: atanzi@cisco.com Domenico La Fauci Cisco Systems via Philips 12 Monza 20052, Italy Email: dlafauci@cisco.com Elio Salvadori CREATE-NET via alla Cascata 56 C, Povo Trento 38100, Italy Email: elio.salvadori@create-net.org Chava Vijaya Saradhi CREATE-NET via alla Cascata 56 C, Povo Trento 38100, Italy Email: saradhi.chava@create-net.org 13. IANA Considerations This memo needs the following request to IANA TLV (see Figure 1 in Section 5) New class type for sender template (see Section 8) All drafts are required to have an IANA considerations section (see the update of RFC 2434 [I-D.narten-iana-considerations-rfc2434bis] for a guide). If the draft does not require IANA to do anything, the Martinelli & Zanardi Expires January 14, 2010 [Page 16] Internet-Draft Optical Impairment Signaling July 2009 section contains an explicit statement that this is the case (as above). If there are no requirements for IANA, the section will be removed during conversion into an RFC by the RFC Editor. 14. Security Considerations This document introduces no new security considerations to [RFC3473]. GMPLS security is described in section 11 of [RFC3471] and refers to [RFC3209] for RSVP-TE. 15. References 15.1. Normative References [ITU.G680] International Telecommunications Union, "Physical transfer functions of optical network elements", ITU- T Recommendation G.680, July 2007. [ITU.G709] International Telecommunications Union, "Interface for the Optical Transport Network (OTN)", ITU-T Recommendation G.709, March 2003. [ITU.G975.1] International Telecommunications Union, "Forward Error Correction for high bit rate DWDM Submarine Systems", ITU- T Recommendation G.975, February 2004. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2205] Braden, B., Zhang, L., Berson, S., Herzog, S., and S. Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1 Functional Specification", RFC 2205, September 1997. [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP Tunnels", RFC 3209, December 2001. [RFC3471] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description", RFC 3471, January 2003. [RFC3473] Berger, L., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource ReserVation Protocol-Traffic Martinelli & Zanardi Expires January 14, 2010 [Page 17] Internet-Draft Optical Impairment Signaling July 2009 Engineering (RSVP-TE) Extensions", RFC 3473, January 2003. [RFC4328] Papadimitriou, D., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Extensions for G.709 Optical Transport Networks Control", RFC 4328, January 2006. [RFC5420] Farrel, A., Papadimitriou, D., Vasseur, JP., and A. Ayyangarps, "Encoding of Attributes for MPLS LSP Establishment Using Resource Reservation Protocol Traffic Engineering (RSVP-TE)", RFC 5420, February 2009. 15.2. Informative References [I-D.bernstein-ccamp-wson-signaling] Bernstein, G., "Signaling Extensions for Wavelength Switched Optical Networks", draft-bernstein-ccamp-wson-signaling-04 (work in progress), July 2009. [I-D.bernstein-wson-impairment-info] Bernstein, G. and C. Systems, "Information Model for Impaired Optical Path Validation", draft-bernstein-wson-impairment-info-02 (work in progress), July 2009. [I-D.ietf-ccamp-gmpls-g-694-lambda-labels] Rabbat, R., "Document: draft-ietf-ccamp-gmpls-g-694-lambda-labels-04.txt", draft-ietf-ccamp-gmpls-g-694-lambda-labels-04 (work in progress), March 2009. [I-D.ietf-ccamp-rwa-wson-framework] Bernstein, G., "Framework for GMPLS and PCE Control of Wavelength Switched Optical Networks (WSON)", draft-ietf-ccamp-rwa-wson-framework-02 (work in progress), March 2009. [I-D.ietf-ccamp-wson-impairments] Bernstein, G., "A Framework for the Control of Wavelength Switched Optical Networks (WSON) with Impairments", draft-ietf-ccamp-wson-impairments-00 (work in progress), June 2009. [I-D.narten-iana-considerations-rfc2434bis] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", draft-narten-iana-considerations-rfc2434bis-09 (work in progress), March 2008. Martinelli & Zanardi Expires January 14, 2010 [Page 18] Internet-Draft Optical Impairment Signaling July 2009 [RFC3945] Mannie, E., "Generalized Multi-Protocol Label Switching (GMPLS) Architecture", RFC 3945, October 2004. [RFC4054] Strand, J. and A. Chiu, "Impairments and Other Constraints on Optical Layer Routing", RFC 4054, May 2005. Authors' Addresses Giovanni Martinelli (editor) Cisco Systems via Philips 12 Monza 20052 Italy Email: giomarti@cisco.com Andrea Zanardi (editor) CREATE-NET via alla Cascata 56 C, Povo Trento 38100 Italy Email: andrea.zanardi@create-net.org Martinelli & Zanardi Expires January 14, 2010 [Page 19]