CCAMP Working Group XianInternet Engineering Task Force (IETF) X. ZhangInternet-Draft HaomianRequest for Comments: 8363 H. ZhengIntended status:Category: Standards Track HuaweiRamonISSN: 2070-1721 R. Casellas CTTC O. Gonzalez de Dios Telefonica D. Ceccarelli EricssonExpires: August 17, 2017 February 17, 2017May 2018 GMPLS OSPF-TE Extensions insupportSupport ofFlexi-grid DWDM networks draft-ietf-ccamp-flexible-grid-ospf-ext-09.txtFlexi-Grid Dense Wavelength Division Multiplexing (DWDM) Networks Abstract The International Telecommunication Union TelecommunicationStandardization Sectorstandardization sector (ITU-T) has extended its Recommendations G.694.1 and G.872 to include a new Dense Wavelength Division Multiplexing (DWDM) grid by defining channel spacings, a set of nominal central frequencies,channel spacings,and the concept of the "frequency slot". Corresponding techniques for data-plane connections are known asflexi-grid."flexi-grid". Based on the characteristics of flexi-grid defined inG.694.1, RFCG.694.1 and in RFCs 7698 and 7699, this document describes theOSPF-TEOpen Shortest Path First - Traffic Engineering (OSPF-TE) extensions in support of GMPLS control of networks that include devices that use the new flexible optical grid. Status ofthisThis Memo ThisInternet-Draftissubmitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documentsan Internet Standards Track document. This document is a product 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(IETF). It represents the consensus ofsix monthsthe IETF community. It has received public review andmay be updated, replaced, or obsoletedhas been approved for publication byother documents at any time. Itthe Internet Engineering Steering Group (IESG). Further information on Internet Standards isinappropriate to use Internet-Drafts as reference material or to cite them other than as "workavailable inprogress." The listSection 2 of RFC 7841. Information about the currentInternet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The liststatus ofInternet-Draft Shadow Directories canthis document, any errata, and how to provide feedback on it may beaccessedobtained athttp://www.ietf.org/shadow.html. This Internet-Draft will expire on August 17, 2017.https://www.rfc-editor.org/info/rfc8363. Copyright Notice Copyright (c)20172018 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)(https://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. Introduction.................................................. . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology................................................... . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Conventions Used inthisThis Document........................ . . . . . . . . . . . 4 3. Requirements forFlexi-gridFlexi-Grid Routing........................... . . . . . . . . . . . . 4 3.1. Available Frequency Ranges............................... . . . . . . . . . . . . . . 4 3.2. Application Compliance Considerations.................... . . . . . . . . . 5 3.3. Comparison withFixed-gridFixed-Grid DWDM Links.................... . . . . . . . . . 6 4. Extensions.................................................... . . . . . . . . . . . . . . . . . . . . . . . . 7 4.1.ISCDInterface Switching Capability Descriptor (ISCD) Extensions forFlexi-grid ..........................Flexi-Grid . . . . . . . . . . . . . . . . 7 4.1.1. Switching Capability Specific Information(SCSI)....(SCSI) . . 8 4.1.2. An SCSI Example.................................... . . . . . . . . . . . . . . . . . . 10 4.2. Extensions to the Port LabelRestriction sub-TLV ........... 12Restrictions Field . . . . . 11 5. IANA Considerations.......................................... . . . . . . . . . . . . . . . . . . . . 13 5.1. New ISCD Switching Type...................................... . . . . . . . . . . . . . . . . 13 5.2. NewSub-TLV ............................................SCSI Type . . . . . . . . . . . . . . . . . . . . . . 13 6.Implementation Status ....................................... 14 6.1. Centre Tecnologic de Telecomunicacions de Catalunya (CTTC)14 7. Acknowledgments ............................................. 15 8.Security Considerations..................................... 15 9. Contributors' Addresses ..................................... 16 10.. . . . . . . . . . . . . . . . . . . 13 7. References................................................. 16 10.1.. . . . . . . . . . . . . . . . . . . . . . . . . 14 7.1. Normative References.................................. 16 10.2.. . . . . . . . . . . . . . . . . . 14 7.2. Informative References................................ 17. . . . . . . . . . . . . . . . . 15 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 16 Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Authors' Addresses.............................................. . . . . . . . . . . . . . . . . . . . . . . 17 1. Introduction [G.694.1] defines the Dense Wavelength Division Multiplexing (DWDM) frequency grids for Wavelength Division Multiplexing (WDM) applications. A frequency grid is a reference set of frequencies used to denote allowed nominal central frequencies that may be used for defining applications. The channel spacing is the frequency spacing between two allowed nominal central frequencies. All of the wavelengths on a fiber should use different central frequencies and occupy a fixed bandwidth of frequency.Fixed gridFixed-grid channel spacing ranges from one of 12.5 GHz, 25 GHz, 50 GHz, or 100 GHz to integer multiples of 100 GHz. But [G.694.1] also defines a "flexiblegrids",grid", also known as "flexi-grid". The terms "frequency slot" (i.e., the frequency range allocated to a specific channel and unavailable to other channels within a flexible grid) and "slot width" (i.e., the full width of a frequency slot in a flexible grid) are used to define a flexible grid. [RFC7698] defines a framework and the associatedcontrol planecontrol-plane requirements for theGMPLS basedGMPLS-based control of flexi-grid DWDM networks. [RFC6163] provides a framework for GMPLS and Path Computation Element (PCE) control of Wavelength Switched Optical Networks(WSONs), and(WSONs). [RFC7688] defines the requirements and OSPF-TE extensions in support of GMPLS control of a WSON. [RFC7792] describes requirements and protocol extensions for signaling to set upLSPsLabel Switched Paths (LSPs) in networks that support theflexi-grid, and thisflexi-grid. This document complements [RFC7792] by describing the requirement and extensions for OSPF-TE routing in a flexi-grid network. This document complements the efforts to provide extensions toOpen Short Path First (OSPF) Traffic-Engineering (TE)the OSPF-TE protocol so as to support GMPLS control of flexi-grid networks. 2. Terminology For terminology related to flexi-grid, please consult [RFC7698] and [G.694.1]. 2.1. Conventions Used inthisThis Document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described inRFC-2119 [RFC2119].BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 3. Requirements forFlexi-gridFlexi-Grid Routing The architecture for establishing LSPs in a Spectrum SwitchedopticalOptical Network (SSON) is described in [RFC7698]. A flexi-grid LSP occupiesaone or multiple specific frequencyslot, i.e., a frequency range.slots. The process of computing a route and the allocation of a frequency slot is referred to asRSA"RSA" (Routing and Spectrum Assignment). [RFC7698] describes three types of architectural approaches to RSA: combined RSA, separated RSA, and routing and distributed SA. The first two approachesamong themcould be called "centralized SA" because the spectrum (frequency slot) assignment is performed by a single entity before the signaling procedure. In the case of centralized SA, the assigned frequency slot is specified in the RSVP-TE Path message during the signaling process. In the case of routing and distributed SA, only the requested slot width of the flexi-grid LSP is specified in the Path message, allowing the involved network elements to select the frequency slot to be used. If the capability of switching or converting the whole optical spectrum allocated to an optical spectrum LSP is not available at nodes along the path of the LSP, the LSP is subject to the Optical "Spectrum Continuity Constraint", as described in [RFC7698]. The remainder of this section states the additional extensions on the routing protocols in a flexi-grid network. 3.1. Available Frequency Ranges In the case of flexi-grids, the central frequency steps from 193.1 THz with 6.25 GHz granularity. The calculation method of central frequency and the frequency slot width of a frequency slot are defined in [G.694.1], i.e., by using nominal central frequency n and the slot width m. On a DWDM link, the allocated or in-use frequency slots do not overlap with each other. However, the border frequencies of two frequency slots may be the same frequency, i.e., the upper bound of a frequency slot and the lower bound of the directly adjacent frequency slot are the same. Frequency Slot 1 Frequency Slot 2 +-----------+-----------------------+ | | | -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 ...+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--... ------------ ------------------------ ^ ^ Central F =193.1THz193.1 THz Central F = 193.1375 THz Slot width = 25 GHz Slot width = 50 GHz Figure1 -1: Two Frequency Slots on a Link Figure 1 shows two adjacent frequency slots on a link. The highest frequency of frequency slot 1 denoted by n=2 is the lowest frequency of slot 2. In this example, it means that the frequency range from n=-2 to n=10 is unavailable to other flexi-grid LSPs. Available central frequencies are advertised for m=1, which means that for an available central frequency n, the frequency slot from central frequency n-1 to central frequency n+1 is available. Hence, in order to clearly show whichLSPsfrequency slots are available and can besupportedused for LSP establishment andwhatwhich frequency slots are unavailable, theavailableavailability of frequencyranges areslots is advertised by the routing protocol for the flexi-grid DWDM links. A set ofnon-overlappingnon- overlapping available frequency rangesareis disseminated in order to allow efficient resource management of flexi-grid DWDM links and RSAproceduresprocedures, which are described in Section 4.8 of [RFC7698]. 3.2. Application Compliance Considerations As described in [G.694.1], devices or applications that make use of the flexi-grid may not be capable of supporting every possible slot width or position (i.e., central frequency). In other words, applications or implementations may be defined where only a subset of the possible slot widths and positions are required to be supported. For example, an application could be defined where the nominal central frequency granularity is 12.5 GHz (by only requiring values of n that are even) andthatthe same application only requires slot widths as a multiple of 25 GHz (by only requiring values of m that are even). Hence, in order to support all possible applications andimplementationsimplementations, the following information SHOULD be advertised for a flexi-grid DWDM link: o Channel Spacing (C.S.): as defined in [RFC7699] for flexi-grid, is set to 5 to denote6.25GHz.6.25 GHz. o Central frequency granularity: a multiplier ofC.S..C.S. o Slot width granularity: a multiplier of2*C.S..2*C.S. o Slot width range: two multipliers of the slot width granularity, eachindicateindicating the minimal and maximal slot width supported by aportport, respectively. The combination of slot width range and slot width granularity can be used to determine the slot widths set supported by a port. 3.3. Comparison withFixed-gridFixed-Grid DWDM Links In the case of fixed-grid DWDM links, each wavelength has apre- definedpredefined centralfrequency and eachfrequency. Each wavelength maps to apre-definedpredefined centralfrequencyfrequency, and the usable frequency range is implicit by the channel spacing. All the wavelengths on a DWDM link can be identified with an identifier that mainly conveys its central frequency as the label defined in[RFC6205], and[RFC6205]; the status of the wavelengths (available or not) can be advertised through a routing protocol. Figure 2 shows a link that supports a fixed-grid with 50 GHz channel spacing. The central frequencies of the wavelengths arepre-definedpredefined by values of"n""n", and each wavelength occupies a fixed 50 GHz frequency range as described in [G.694.1]. W(-2) | W(-1) | W(0) | W(1) | W(2) | ...---------+-----------+-----------+-----------+-----------+----... | 50 GHz | 50 GHz | 50 GHz | 50 GHz | n=-2 n=-1 n=0 n=1 n=2 ...---+-----------+-----------+-----------+-----------+----------... ^ Central F =193.1THz193.1 THz Figure2 -2: A Link Supports Fixed Wavelengths with 50 GHz Channel Spacing Unlike the fixed-grid DWDM links, on a flexi-grid DWDMlinklink, the slot width of the frequency slot isflexibleflexible, as described insectionSection 3.1. That is, the value of m in the following formula from [G.694.1] is uncertain before a frequency slot is actually allocated for a flexi- grid LSP. Slot Width(GHz)(in GHz) = 12.5GHz * m For this reason, the available frequencyslot/rangesslots (or ranges) are advertised for a flexi-grid DWDM link instead of the specific"wavelengths""wavelength" points that are sufficient for a fixed-grid link. Moreover, this advertisement is represented by the combination ofCentral Frequency Granularitycentral frequency granularity andSlot Width Granularity.slot width granularity. 4. ExtensionsAs described in [RFC7698], the network connectivityThe network-connectivity topology constructed by thelinks/nodeslinks and/or nodes and node capabilities are the same as for WSON, as described in [RFC7698], and they can be advertised by the GMPLS routing protocols usingopaque LSAsOpaque Link State Advertisements (LSAs) [RFC3630] in the case of OSPF-TE [RFC4203] (refer tosectionSection 6.2 of [RFC6163]). In the flexi-grid case, the available frequencyrangesranges, instead of the specific"wavelengths""wavelengths", are advertised for the link. This section defines the GMPLS OSPF-TE extensions in support of advertising the available frequency ranges for flexi-grid DWDM links. 4.1.ISCDInterface Switching Capability Descriptor (ISCD) Extensions forFlexi-gridFlexi-Grid This section defines a new value for the Switching Capability field of the ISCD with a value of 152 and type name Flexi-Grid-LSC. ValueTypeName ----------------------- 152(TBA by IANA)Flexi-Grid-LSC Switching Capability and Encoding values MUST be used as follows: Switching Capability = Flexi-Grid-LSC Encoding Type = lambda[as(as defined inRFC3471][RFC3471]) When the Switching Capability and Encoding fields are set to values as stated above, theInterface Switching Capability DescriptorISCD is interpreted as in [RFC4203] with the optional inclusion of one or more Switching Capability Specific Information (SCSI) sub-TLVs. As the "Max LSP Bandwidth at priority x" (x from 0 to 7) fields in the generic part of theInterface Switching Capability DescriptorISCD [RFC4203] are not meaningful forflexi-gridflexi- grid DWDM links, the values of these fields MUST be set to zero and MUST be ignored. TheSwitching Capability Specific Information (SCSI)SCSI as defined below provides the corresponding information for flexi-grid DWDM links. 4.1.1. Switching Capability Specific Information (SCSI) [RFC8258] defines a Generalized SCSI for the ISCD. This document defines the Frequency Availability Bitmap as a new type of the Generalized SCSI TLV. Thetechnology specifictechnology-specific part of theFlexi-gridflexi-grid ISCD includes the availablefrequency spectrumfrequency-spectrum resource as well as the information regarding max slot widths perpriority information.priority. The format of thisflex-gridflexi-grid SCSI, thefrequency available bitmap TLV,Frequency Availability Bitmap sub-TLV, is depicted in the following figure: 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 =111 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Priority | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Max Slot Width at Priority k | UnreservedpaddingPadding ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | C.S. | Starting n | No. ofEffective. Bits|Effective Bits | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Bit MapBitmap ... ~ ~ ... | padding bits ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type (16 bits): The type of this sub-TLVand is set to 1.(11). Length (16 bits): The length of the value field of thissub-TLV,sub-TLV in octets. Priority (8 bits): A bitmap used to indicate which priorities are being advertised. The bitmap is in ascending order, with the leftmost bit representing priority level 0 (i.e., the highest) and the rightmost bit representing priority level 7 (i.e., the lowest). A bit is set (1) corresponding to each priority represented in thesub-TLV,sub-TLV and clear (0) for each priority not represented in thesub-TLV.sub- TLV. At least one priority level MUST be advertised. If only one priority level is advertised, it MUST be at priority level 0. Reserved: The Reserved field MUST be set to zero on transmission and MUST be ignored on receipt. Max Slot Width atpriority k(16Priority k (16 bits): This field indicates maximal frequency slot width supported at a particular priority level, up to 8. This field is set to max frequency slot width supported in the unit of 2*C.S., for a particular priority level. One field MUST be present for each bit set in the Priority field, and each present field is ordered to match the Priority field. Fields MUST be present for priority levels that are indicated in the Priority field. Unreserved Padding (16 bits): The Padding field is used to ensure the32 bit32-bit alignment of Max Slot Widthfields.at Priority k. Whenthe number of prioritiesk isodd,an odd number, the Unreserved Padding field MUST be included. Whenthe number of prioritiesk iseven,an even number, the Unreserved Padding field MUST be omitted. This field MUST be set to 0 and MUST be ignored on receipt. C.S. (4 bits): As defined in[RFC7699] and[RFC7699]; it is currently set to 5. Starting n (16 bits):asAs defined in[RFC7699] and this[RFC7699]. This value denotes the starting point of the nominal central frequencypointof the frequency availability bitmap sub-TLV.NumberNo. of Effective Bits (12 bits): Indicates the number of effective bits in theBit MapBitmap field.Bit MapBitmap (variable): Indicates whether or not a basic frequency slot, characterized by a nominal central frequency and a fixed m value of 1, is availableor notfor flexi-grid LSP setup. The first nominal central frequency is the value of startingn and with then; subsequentonesnominal central frequencies are implied by the position in the bitmap. Note thatwhensetting to1, it means1 indicates that the corresponding central frequency is available for a flexi-grid LSP withm=1;m=1 andwhensetting to0, it means0 indicates the corresponding central frequency is unavailable. Note that a centralized SA process will need to extend this to high values of m by checking asufficientsufficiently large number of consecutive basic frequency slots that are available.Padding Bitspadding bits (variable): Padded after theBit MapBitmap to make it a multiple of fourbytesbytes, if necessary. Padding bits MUST be set to 0 and MUST be ignored on receipt. An example is provided insectionSection 4.1.2. 4.1.2. An SCSI Example Figure 3 shows an example of the available frequency spectrum resource of a flexi-grid DWDM link. -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 ...+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--... |--Available Frequency Range--| Figure3 - Flexi-grid3: Flexi-Grid DWDM Link Example The symbol "+" represents the allowed nominal central frequency. The symbol "--" represents a central frequency granularity of 6.25 GHz,aswhich is currentlybestandardized in [G.694.1]. The number on the top of the line represents the "n" in the frequency calculation formula (193.1 + n * 0.00625). The nominal central frequency is 193.1 THz when n equals zero. In this example, it is assumed that the lowest nominal central frequency supported isn= -9n=-9 and the highest is n=11. Note they cannot be used as a nominal central frequency for setting upaan LSP, but merely as the way to express the supported frequency range. Using the encoding defined in Section 4.1.1, the relevant fields to express the frequency resource availability can be filled as below: 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 =111 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Priority | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Max Slot Width at Priority k | UnreservedpaddingPadding ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 5 | Starting n (-9) | No. of Effec. Bits(21)| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|0|0|0|0|0|0|1|1|1|1|1|1|1|1|1|0|0|0|0| padding bits (0s) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ In the above example, the starting n is selected to be the lowest nominal central frequency,i.e.i.e., -9. It is observed from thebit mapbitmap thatn = -1n=-1 to 7 can be used to set up LSPs. Note other starting n values can be chosen to represent thebit map,bitmap; for example, the first available nominal central frequency (a.k.a., the first available basic frequency slot) can bechosenchosen, and the SCSI will be expressed as the following: 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 =111 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Priority | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Max Slot Width at Priority k | UnreservedpaddingPadding ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 5 | Starting n (-1) | No. of Effec. Bits(9)| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|1|1|1|1|1|1|1|1| padding bits (0s) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ This encoding denotesthatthat, other than the advertised available nominal central frequencies, the other nominal central frequencies within the whole frequency range supported by the link are not available for flexi-grid LSPset up.setup. Ifaan LSP with slot width mequalsequal to 1 is set up using this link, say usingn= -1,n=-1, then the SCSI information is updated to be the following: 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 =111 | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Priority | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ~ Max Slot Width at Priority k | UnreservedpaddingPadding ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 5 | Starting n (-1) | No. of Effec. Bits(9)| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|0|1|1|1|1|1|1|1| padding bits (0s) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 4.2. Extensions to the Port LabelRestriction sub-TLVRestrictions Field As described in Section 3.2, a port that supports flexi-grid may support only a restricted subset of the full flexible grid. The Port LabelRestrictionRestrictions field is defined in [RFC7579]. It can be used to describe the label restrictions on a port and is carried in thetop-leveltop- level Link TLV as specified in [RFC7580]. A new restriction type, the flexi-grid Restriction Type, is defined here to specify the restrictions on a port to support flexi-grid. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | MatrixID | RstType = 5 | Switching Cap | Encoding | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | C.S. | C.F.G | S.W.G | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Min Slot Width | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ MatrixID (8 bits): As defined in [RFC7579]. RstType (Restriction Type, 8 bits): Takes the value of 5 to indicate the restrictions on a port to support flexi-grid. Switching Cap (Switching Capability, 8 bits): As defined in [RFC7579], MUST be consistent with the one specified in ISCD as described in Section 4.1. Encoding (8 bits): As defined in [RFC7579], MUST be consistent with the one specified in ISCD as described in Section 4.1. C.S. (4 bits): As defined in[RFC7699] and for flexi-grid[RFC7699]. For flexi-grid, it is 5 to denote6.25GHz.6.25 GHz. C.F.G (Central Frequency Granularity, 8 bits): A positive integer. Its value indicates the multiple of C.S., in terms of central frequency granularity. S.W.G (Slot Width Granularity, 8 bits): A positive integer. Its value indicates the multiple of 2*C.S., in terms of slot width granularity. Min Slot Width (16 bits): A positive integer. Its value indicates the multiple of 2*C.S.(GHz),(in GHz), in terms of the supported minimal slot width. Reserved: The Reserved field MUST be set to zero on transmission and SHOULD be ignored on receipt. 5. IANA Considerations 5.1. New ISCD Switching TypeUpon approval of this document,IANAwill makehas made the following assignment in the "Switching Types"sectionsub- registry of the"GMPLS"Generalized Multi-Protocol Label Switching (GMPLS) Signaling Parameters" registry located athttp://www.iana.org/assignments/gmpls-sig- parameters:<https://www.iana.org/assignments/gmpls-sig-parameters>: Value Name Reference--------- --------------------------------- ---------------- ---------- 152(*)Flexi-Grid-LSC[This.I-D] (*) Suggested valueRFC 8363 5.2. NewSub-TLVSCSI Type This document definesonea new generalized SCSI sub-TLV thatareis carried in the Interface Switching Capability Descriptors [RFC4203]with Signalwhen the Switching Type is set to Flexi-Grid-LSC.Upon approval of this document,IANAwill create and maintain a new sub-registry,has made the"Types for sub-TLVs of Flexi-Grid-LSC SCSI (Switch Capability-Specific Information)" registry underfollowing assignment in the"Open Shortest Path First (OSPF) Traffic Engineering TLVs" registry, see http://www.iana.org/assignments/ospf-traffic-eng-tlvs/ospf-traffic- eng-tlvs.xml, with"Generalized SCSI (Switching Capability Specific Information) TLV Types" sub-registry [RFC8258] of thesub-TLV types as follows: This document defines new sub-TLV types as follows:"Generalized Multi-Protocol Label Switching (GMPLS) Signaling Parameters" registry located at <https://www.iana.org/assignments/gmpls-sig-parameters>: ValueSub-TLVSCSI-TLV Switching Type Reference ----- ----------------------------- -------------- ----------------------------------- ---------- 0 Reserved [This.I-D] 111 Frequencyavailability bitmap [This.I-D] 8.Availability Bitmap 152 RFC 8363 6. Security Considerations This document extends [RFC4203] and [RFC7580] to carryflex-gridflexi-grid- specific information in OSPF Opaque LSAs. This document does not introduce any further security issues other than those discussed in[RFC3630],[RFC3630] and [RFC4203]. To be more specific, the security mechanisms described in[RFC2328][RFC2328], which apply to Opaque LSAs carried inOSPFOSPF, still apply. An analysis of the OSPF security is provided in [RFC6863] and applies to the extensions to OSPF in this document as well.10.7. References10.1.7.1. Normative References [G.694.1] International Telecommunication Union, "Spectral grids for WDM applications: DWDM frequency grid", ITU-T Recommendation G.694.1, February 2012, <https://www.itu.int/rec/T-REC-G.694.1/en>. [RFC2119]S.Bradner, S., "Key words for use in RFCs toindicate requirements levels",Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March1997. [G.694.1] ITU-T Recommendation G.694.1 (revision 2), "Spectral grids for WDM applications: DWDM frequency grid", February 2012.1997, <https://www.rfc-editor.org/info/rfc2119>. [RFC3471] Berger, L., Ed., "Generalized Multi-Protocol Label Switching (GMPLS) Signaling Functional Description", RFC 3471, DOI 10.17487/RFC3471, January 2003, <https://www.rfc-editor.org/info/rfc3471>. [RFC4203]K.Kompella, K., Ed. and Y. Rekhter," OSPFEd., "OSPF Extensions in Support of Generalized Multi-Protocol Label Switching (GMPLS)", RFC 4203, DOI 10.17487/RFC4203, October2005.2005, <https://www.rfc-editor.org/info/rfc4203>. [RFC6205] Otani, T., Ed. and D. Li, Ed., "Generalized Labels for Lambda-Switch-Capable (LSC) Label Switching Routers", RFC 6205, DOI 10.17487/RFC6205, March 2011, <https://www.rfc-editor.org/info/rfc6205>. [RFC7579] Bernstein, G., Ed., Lee, Y., Ed., Li, D.,and W.Imajuku, W., and J. Han, "General Network Element Constraint Encoding forGMPLS ControlledGMPLS-Controlled Networks", RFC 7579, DOI 10.17487/RFC7579, June2015.2015, <https://www.rfc-editor.org/info/rfc7579>. [RFC7580]F.Zhang,Y.F., Lee,J.Y., Han,G. BernsteinJ., Bernstein, G., and Y. Xu, "OSPF-TE Extensions for General Network ElementConstraints ",Constraints", RFC 7580, DOI 10.17487/RFC7580, June2015. [RFC6205] T. Otani and D. Li, "Generalized Labels for Lambda-Switch- Capable (LSC) Label Switching Routers", RFC 6205, March 2011.2015, <https://www.rfc-editor.org/info/rfc7580>. [RFC7699] Farrel, A., King, D.,Farrel, A. and Y.Li, Y., and F. Zhang, "Generalized Labels for the Flexi-Grid in Lambda Switch Capable (LSC) Label Switching Routers",RFC7699, September 2015. 10.2. Informative References [RFC6163] Y. Lee, G. Bernstein and W. Imajuku, "Framework for GMPLS and Path Computation Element (PCE) Control of Wavelength Switched Optical Networks (WSONs)",RFC6163, April 2011. [RFC7792] F.Zhang et al, "RSVP-TE Signaling Extensions7699, DOI 10.17487/RFC7699, November 2015, <https://www.rfc-editor.org/info/rfc7699>. [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase insupport of Flexible-grid",RFC7792, November 2015. [RFC7698] Gonzalez de Dios, O., Casellas R., Zhang, F., Fu, X.,2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, <https://www.rfc-editor.org/info/rfc8174>. [RFC8258] Ceccarelli,D., and I. Hussain, "FrameworkD. andRequirementsL. Berger, "Generalized SCSI: A Generic Structure forGMPLS based control of Flexi-grid DWDM networks',Interface Switching Capability Descriptor (ISCD) Switching Capability Specific Information (SCSI)", RFC7698, August 2015. [RFC7688] Y. Lee and G. Bernstein, "GMPLS OSPF Enhancement for Signal and Network Element Compatibility for Wavelength Switched Optical Networks ", RFC7688, August 2015.8258, DOI 10.17487/RFC8258, October 2017, <https://www.rfc-editor.org/info/rfc8258>. 7.2. Informative References [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, DOI 10.17487/RFC2328, April1998.1998, <https://www.rfc-editor.org/info/rfc2328>. [RFC3630]D.Katz,K.D., Kompella, K., and D. Yeung," Traffic"Traffic Engineering (TE) Extensions to OSPF Version 2", RFC 3630, DOI 10.17487/RFC3630, September2003.2003, <https://www.rfc-editor.org/info/rfc3630>. [RFC6163] Lee, Y., Ed., Bernstein, G., Ed., and W. Imajuku, "Framework for GMPLS and Path Computation Element (PCE) Control of Wavelength Switched Optical Networks (WSONs)", RFC 6163, DOI 10.17487/RFC6163, April 2011, <https://www.rfc-editor.org/info/rfc6163>. [RFC6863] Hartman, S. and D. Zhang, "Analysis of OSPF Security According to the Keying and Authentication for Routing Protocols (KARP) Design Guide", RFC 6863, DOI 10.17487/RFC6863, March2013. 7.2013, <https://www.rfc-editor.org/info/rfc6863>. [RFC7688] Lee, Y., Ed. and G. Bernstein, Ed., "GMPLS OSPF Enhancement for Signal and Network Element Compatibility for Wavelength Switched Optical Networks", RFC 7688, DOI 10.17487/RFC7688, November 2015, <https://www.rfc-editor.org/info/rfc7688>. [RFC7698] Gonzalez de Dios, O., Ed., Casellas, R., Ed., Zhang, F., Fu, X., Ceccarelli, D., and I. Hussain, "Framework and Requirements for GMPLS-Based Control of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM) Networks", RFC 7698, DOI 10.17487/RFC7698, November 2015, <https://www.rfc-editor.org/info/rfc7698>. [RFC7792] Zhang, F., Zhang, X., Farrel, A., Gonzalez de Dios, O., and D. Ceccarelli, "RSVP-TE Signaling Extensions in Support of Flexi-Grid Dense Wavelength Division Multiplexing (DWDM) Networks", RFC 7792, DOI 10.17487/RFC7792, March 2016, <https://www.rfc-editor.org/info/rfc7792>. Acknowledgments This work was supported in part by the FP-7 IDEALIST project under grant agreement number 317999. This work was supported in part by NSFC Project 61201260.9. Contributors' AddressesContributors Adrian Farrel Juniper Networks Email: afarrel@juniper.net Fatai Zhang Huawei Technologies Email: zhangfatai@huawei.com LeiWang,Wang Beijing University of Posts and Telecommunications Email: wang.lei@bupt.edu.cn GuoyingZhang,Zhang China Academy of Information and Communication Technology Email: zhangguoying@ritt.cn Authors' Addresses Xian Zhang Huawei Technologies Email: zhang.xian@huawei.com Haomian Zheng Huawei Technologies Email: zhenghaomian@huawei.com Ramon Casellas, Ph.D. CTTC Spain Phone: +34 936452916 Email: ramon.casellas@cttc.es Oscar Gonzalez de Dios Telefonica Investigacion y Desarrollo Emilio Vargas 6 Madrid, 28045 Spain Phone: +34 913374013 Email:ogondio@tid.esoscar.gonzalezdedios@telefonica.com Daniele Ceccarelli Ericsson Via A. Negrone 1/A Genova - Sestri Ponente Italy Email: daniele.ceccarelli@ericsson.com