TVR Z. Zhang Internet-Draft H. Wu Intended status: Standards Track ZTE Corporation Expires: 9 September 2023 8 March 2023 IS-IS and OSPF extensions for TVR (Time-Variant Routing) draft-zw-tvr-igp-extensions-00 Abstract TVR needs IGP to calculate different results depending on the time, without convergence after the detection of link or nodes. IGP nodes need to learn the predictable and scheduled changes in advance. This document defines the IGP extensions for predictable and scheduled changes of TVR. 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 9 September 2023. Copyright Notice Copyright (c) 2023 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 Revised BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Revised BSD License. Zhang & Wu Expires 9 September 2023 [Page 1] Internet-Draft Abbreviated Title March 2023 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Time Variant Algorithm . . . . . . . . . . . . . . . . . . . 3 4. Time Variant sub-TLVs of IS-IS and OSPF FAD Sub-TLV . . . . . 3 5. Handling of the time variant sub-TLV . . . . . . . . . . . . 4 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 6.1. IGP Metric-type Registry . . . . . . . . . . . . . . . . 4 6.2. IS-IS Registry . . . . . . . . . . . . . . . . . . . . . 4 6.3. OSPF Registry . . . . . . . . . . . . . . . . . . . . . . 4 7. Security Considerations . . . . . . . . . . . . . . . . . . . 5 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 8.1. Normative References . . . . . . . . . . . . . . . . . . 5 8.2. Informative References . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction [I-D.birrane-tvr-use-cases] and [I-D.king-tvr-ntn-challanges] describe a new challenge for non-terrestrial networks. In these networks, there are predictable and scheduled changes of link or nodes. The affected nodes which connected the changing link or node advertise the changes after finding the changes. After convergence all the nodes calculate a new routing table. But for the predictable and scheduled changes, the nodes can advertise the changes and do the calculation in advance to reduce the convergence time. This document defines the a set of extensions to IS-IS, OSPFv2 and OSPFv3 for predictable and scheduled changes of TVR. These extensions can be advertised by the node self which has predictable and scheduled changes, or by the node which connected or adjacenct to the node which has predictable and scheduled changes. 1.1. 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]. 2. Terminology TBD. Zhang & Wu Expires 9 September 2023 [Page 2] Internet-Draft Abbreviated Title March 2023 3. Time Variant Algorithm The predictable and scheduled changes can be looked as a net of new constrains which defined in [RFC9350]. The new constrains are advertised as new sub-tlvs. 4. Time Variant sub-TLVs of IS-IS and OSPF FAD Sub-TLV A new type of Metric-Type is defined for time variant in IS-IS FAD sub-TLV which defined in section 5.1 [RFC9350] and OSPF FAD sub-TLV which defined in section 5.2 [RFC9350]. A new Time Variant sub-TLV is advertised as a sub-TLV of IS-IS FAD sub-TLV and OSPF FAD sub-TLV. The Time Variant sub-TLV has following formats: 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Metric1 | | Time-slot1-begin | | Time-slot1-end | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Metric2 | | Time-slot2-begin | | Time-slot2-end | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | . | . . . | . | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Metric[m] | | Time-slot[m]-begin | | Time-slot[m]-end | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1 Type: 1-octet. TBD (To be assigned by IANA). Length: 1-octet. The number of the set of metric and time-slot. Metric: 4-octet. The metric value of specific time slot. The value of 0xffffffff indicates unreachable. Time-slot-begin: 4-octet. The begin time of this time-slot. Zhang & Wu Expires 9 September 2023 [Page 3] Internet-Draft Abbreviated Title March 2023 Time-slot-end: 4-octet. The end time of this time-slot. 5. Handling of the time variant sub-TLV The handling follows the definition in [RFC9350], except one or more timers are scheduled for different time-slot carried in time variant sub-tlv. When a scheduled time-slot is coming, the associated routing table needs to be calculated with the associated metric. 6. IANA Considerations The document requests new allocations from the IANA registries as follows: 6.1. IGP Metric-type Registry IANA is requested to allocate a new code points from the "IGP Metric- Type" registry. +======+=====================+===============+ | Type | Description | Reference | +======+=====================+===============+ | TBD1 | Time Variant metric | This Document | +------+---------------------+---------------+ Table 1: IGP Metric-Type 6.2. IS-IS Registry IANA is requested to allocate a new code points from the "IS-IS Sub- Sub-TLVs for Flexible Algorithm Definition Sub-TLV" registry. +======+==============+===============+ | Type | Description | Reference | +======+==============+===============+ | TBD2 | Time Variant | This Document | +------+--------------+---------------+ Table 2: IS-IS TVR sub-TLV 6.3. OSPF Registry IANA is requested to allocate a new code points from the "OSPF Flexible Algorithm Definition TLV Sub-TLVs" registry. Zhang & Wu Expires 9 September 2023 [Page 4] Internet-Draft Abbreviated Title March 2023 +======+==============+===============+ | Type | Description | Reference | +======+==============+===============+ | TBD3 | Time Variant | This Document | +------+--------------+---------------+ Table 3: OSPF TVR sub-TLV 7. Security Considerations This document does not introduce more security consideration than [RFC9350]. 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC9350] Psenak, P., Ed., Hegde, S., Filsfils, C., Talaulikar, K., and A. Gulko, "IGP Flexible Algorithm", RFC 9350, DOI 10.17487/RFC9350, February 2023, . 8.2. Informative References [I-D.birrane-tvr-use-cases] Birrane, E. J., "TVR (Time-Variant Routing) Use Cases", Work in Progress, Internet-Draft, draft-birrane-tvr-use- cases-00, 24 October 2022, . [I-D.king-tvr-ntn-challanges] King, D. and K. Shortt, "Time Variant Challenges for Non- Terrestrial Networks", Work in Progress, Internet-Draft, draft-king-tvr-ntn-challanges-00, 17 January 2023, . Authors' Addresses Zheng Zhang ZTE Corporation China Zhang & Wu Expires 9 September 2023 [Page 5] Internet-Draft Abbreviated Title March 2023 Email: zhang.zheng@zte.com.cn Haisheng Wu ZTE Corporation China Email: wu.haisheng@zte.com.cn Zhang & Wu Expires 9 September 2023 [Page 6]