Network Working Group Vijayanand Chandrasekar INTERNET DRAFT Individual Contributor Intended Status: Standards Track August 16, 2019 Expires: 15 Febraury, 2020 Advertising OTN Fixed Time slot constraints in OSPF draft-vijay-ccamp-ospf-otn-timeslot-00.txt Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. 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." This Internet-Draft will expire on January 31, 2020. Copyright Notice Copyright (c) 2019 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 (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. Abstract Vijayanand C Expires February 2020 [Page 1] INTERNET DRAFT OTN fixed Timeslot constraints in OSPF August 2019 This document describes the extensions needed to OSPF for advertising the constraints that exists in some OTN switches while switching timeslots between ports. This advertisement would be needed for computing path of LSP through these switches taking into account the above mentioned constraint. This document proposes extensions to existing OSPF for advertising the timeslots available on each OTN port in a new sub-tlv and the connectivity matrix representing the capability of the device to cross connect these timeslots in another new sub-tlv 1. Introduction In [RFC7138], a mechanism for advertising the ODU multiplexing hierarchy is described. In [RFC7580], an optical node property TLV is defined as an extension to the OSPF opaque LSA defined in {RFC3630]. . This document describes the use of OSPF-TE in carrying information about the details of OTN time slots available in each port of an OTN switch and the connectivity matrix describing the connectivity between the timeslots of the different ports. 2. Terminology 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 [RFC2110]. The reader is assumed to be familiar with the terminology in RFC7138[RFC7138],RFC5780[RFC7580] and RFC3630{RFC3630] 3. OSPF Extensions A new OTN timeslot sub-TLV and OTN Connectivity matrix sub-TLV are proposed in this document. The OTN timeslot sub-TLV will be used in conjunction with the SCSI described in section 4.1 of RFC7138[RFC7138]. The OTN connectivity matrix will be carried in the Optical node property TLV described in RFC7580[RFC7580] 3.1 OTN Timeslot 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 {TBD) | Length | Vijayanand C Expires February 2020 [page 2 ] INTERNET DRAFT OTN fixed Timeslot constraints in OSPF August 2019 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Pri | Bitmap Length | G | BitMap(variable length) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BitMap(variable length) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Pri | Bitmap Length | G| BitMap(variable length) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BitMap(variable length) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type TBD Length Length of Sub-TLV Pri Priority level (0-7) at which the bitmap is advertised G: Timeslot granularity 0 - 1.25 Gbps 1 - 2.5 Gbps 2 - 5 Gbps Priority (0-7) at which the bitmap is available Bitmap Length Length in bits of the bitmap following this BitMap The bitmap represents the timeslots available which is advertised through this sub-TLB. A 1 in the bit position represents that the timeslot is available , while a 0 represents that the timeslot is not available.The Bitmap is padded to the nearest byte boundary. 3.2 Connectivity matrix sub-TLV Vijayanand C Expires February 2020 [page 3 ] INTERNET DRAFT OTN fixed Timeslot constraints in OSPF August 2019 The Connectivity matrix TLV is described 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( TBD) | Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Number of Link pairs | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Number of Bitmap pair pairs | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Bit Map Length | G | TimeSlot BitMap | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BitMap(contd) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Bit Map Length |G | TimeSlot BitMap | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BitMap(contd) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ . . . . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Link Identifier | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Number of Bitmap pair pairs | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Bit Map Length |G | TimeSlot BitMap | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BitMap(contd) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Bit Map Length |G | TimeSlot BitMap | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | BitMap(contd) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Type TBD Vijayanand C Expires February 2020 [page 4 ] INTERNET DRAFT OTN fixed Timeslot constraints in OSPF August 2019 Length Length of Sub-TLV Number of Link pairs The number of pair of link identifiers advertised. Link Identifier An identifier for the port that is described Number of Bitmap pairs The number of pair of bitmaps advertised. Bit Map Length Length in bits of the bitmap G Timeslot granularity 0:1.25 Gbps 1:2.5 Gbps 2:5 Gbps Timeslot BitmAp The BitMap representing the timeslots 4. Operational overview This section details the operation of the scheme proposed in this document. On some OTN switches there exists constraints on which OTN timeslots can be cross connected to which other OTN timeslots. Therefore, the node computing the path through such switches needs to be aware of the OTN timeslots which are available and to which other timeslots they can be cross connected. The OTN timeslot sub-TLV is advertised along with the SCSI defined in section 4.1 of RFC7138[RFC7138] as a separate sub-tlv of the link tlv. The SCSI in RFC7138[RFC7138] only advertises the number of timeslots available whereas this sub-TLV defines the exact timeslots which are available in the form a bitmap. Vijayanand C Expires February 2020 [page 5 ] INTERNET DRAFT OTN fixed Timeslot constraints in OSPF August 2019 The connectivity matrix sub-TLV is advertised in the node attribute TLV of the opaque LSA defined in RFC3630[RFC3630} in line with the connectivity matrix that is advertised in [RFC7580]. This advertisement describes exactly which timeslots of an OTN interface can be cross connected to which other timeslots of another OTN Interface. For every pair of link identifiers, multiple pairs of bitmaps are advertised, this denotes that timeslots, of the first interface in the interface identifier pair, identified in the first bitmap of the bitmap pair can be cross connected to timeslots, of the second interface in the interface identifier pair, identified in the second bitmap of the bitmap pair. Like this several interface pairs and their corresponding bitmap pairs can be advertised. For example, if on Interface I1 timeslots (t1,t3,t5) can be cross- connected to timeslots ( t2,t4,t6) on Interface I2 and ( t2,t4,t6)on Interface I1 can be cross-connected to (t1,t3,t5) on Interface I2, then there will be one interface Identifier pair (I1,I2) advertised with two bitmap pairs corresponding to (t1,t3,t5), (t2,t4,t6) and ( t2,t4,t6), ( t1,t3,t5) The above mentioned sub-TLVs together would help the node which is computing the path to determine which timeslot to select on each of the OTN ports to route the LSP on OTN switches which have restriction on cross connecting OTN timeslots. 5. Interoperability Considerations The feature described in this document would be operational only if all the OSPF routers in area support the extension described above. 6. Security considerations None 7. IANA Considerations IANA needs to allocate a new Type for the OTN timeslot sub-TLV described in section 3.1 and a new Type for the connectivity matrix sub-TLV described in section 3.2 8. Authors' Address Vijayanand Chandrasekar Individual Contributor Email: vijayanandc159@outlook.com 9. References Vijayanand C Expires February 2020 [page 6 ] INTERNET DRAFT OTN fixed Timeslot constraints in OSPF August 2019 9.1 Normative References [RFC7138], D. Ceccarelli, F. Zhang, S. Belotti, R. Rao and J. Drake, " Traffic Engineering Extensions to OSPF for GMPLS Control of Evolving G.709 Optical Transport Networks ",RFC7138,March 2014. [RFC7580], F. Zhang, Y. Lee, J.Han, G. Bernstein and Y. Xu, " OSPF- TE Extensions for General Network Element Constraints ",RFC7580, June 2015. [RFC3630], D. Katz, K. Kompella and D. Yeung, " Traffic Engineering (TE) Extensions to OSPF Version 2", RFC3630, September 2003 . 9.2 Informative references [RFC2110] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119, March 1997. [RFC5226] T. Narten and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", RFC 5226. 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