LSR WG C. Barth Internet-Draft T. Li Intended status: Standards Track V. P. Beeram Expires: 24 December 2026 R. Bonica HPE 22 June 2026 Using IS-IS To Advertise Power Group Membership draft-many-lsr-power-group-03 Abstract Many networks have a daily utilization pattern. For example, a network might be busy during the day and less busy at night. If the network is robust, it has enough capacity to satisfy demand during peak hours and excess capacity during non-peak hours. That excess capacity increases energy costs and environmental impact. [I-D.many-teas-power-steering] introduces a Power Conserving Path Placement Strategy (PCPPS). When possible, PCPPS concentrates traffic onto a small set of network resources. When traffic is concentrated onto a small set of network resources, other network resources become idle and can be powered down until they are needed again. This solves the problem of excess capacity during non-peak hours. PCPPS uses information that is distributed by an IGP. This document specifies the IS-IS encoding for that information. 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 24 December 2026. Barth, et al. Expires 24 December 2026 [Page 1] Internet-Draft IS-IS PG June 2026 Copyright Notice Copyright (c) 2026 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions and Definitions . . . . . . . . . . . . . . . . . 3 2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 3. Link State Database (LSDB) Elements . . . . . . . . . . . . . 3 3.1. The Power Group TLV . . . . . . . . . . . . . . . . . . . 3 3.2. The Sleeping Adjacencies TLV . . . . . . . . . . . . . . 4 3.3. Interface Extensions . . . . . . . . . . . . . . . . . . 5 3.3.1. The Power Group Member Sub-TLV . . . . . . . . . . . 5 3.3.2. The Interface PSP Sub-TLV . . . . . . . . . . . . . . 6 3.3.3. Unidirectional Sleeping Bandwidth Sub-TLV . . . . . . 6 3.3.4. The Power-Sleep Capable Bit . . . . . . . . . . . . . 7 4. Security Considerations . . . . . . . . . . . . . . . . . . . 7 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 7. Normative References . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 1. Introduction Many networks have a daily utilization pattern. For example, a network might be busy during the day and less busy at night. If the network is robust, it has enough capacity to satisfy demand during peak hours and excess capacity during non-peak hours. That excess capacity increases energy costs and environmental impact. Barth, et al. Expires 24 December 2026 [Page 2] Internet-Draft IS-IS PG June 2026 [I-D.many-teas-power-steering] introduces a Power Conserving Path Placement Strategy (PCPPS). When possible, PCPPS concentrates traffic onto a small set of network resources. When traffic is concentrated onto a small set of network resources, other network resources become idle and can be powered down until they are needed again. This solves the problem of excess capacity during non-peak hours. PCPPS uses information that is distributed by an IGP. This document specifies the IS-IS encoding for that information. 2. Conventions and Definitions 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 in BCP14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 2.1. Terminology The following terms are used as defined in [I-D.many-teas-power-steering]: * Power Group * Sleep Status, AWAKE and ASLEEP * Power Savings Potential (PSP) 3. Link State Database (LSDB) Elements 3.1. The Power Group TLV The Power Group TLV is a top level TLV. If a Power Group is sleep- capable, it is advertised by IS-IS and appears in the LSDB. Otherwise, it is not advertised by IS-IS and it does not appear in the LSDB. Barth, et al. Expires 24 December 2026 [Page 3] Internet-Draft IS-IS PG June 2026 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 | Power Group Identifier +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Power Group Identifier (cont.)| PSP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ PSP (cont.) | Parent Identifier +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Parent Identifier (cont.) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 1: Power Group TLV Where: * Type: 1 octet, value TBD1 * Length: 1 octet, unsigned integer. Value 12. * Power Group Identifier: 4 octets, selector. MUST NOT be equal to 0. * PSP: 4 octets, unsigned integer. The Power Group's PSP, in milliwatts. * Parent Identifier: 4 octets, selector. The Power Group Identifier has node-local significance. If the Parent Identifier is equal to 0, the Power Group has no parent (i.e., it is the root of a Power Group hierarchy). Otherwise, the Parent Identifier MUST NOT be set to 0. 3.2. The Sleeping Adjacencies TLV The Sleeping Adjacencies TLV is a top level TLV. An adjacency is sleeping if it satisfies the following criteria: * It has been UP in the past * It is not currently UP * All of the interfaces that supports it are ASLEEP. The Sleeping Adjacencies TLV can include TLVs 22, 23, 141, 222 and 223. Barth, et al. Expires 24 December 2026 [Page 4] Internet-Draft IS-IS PG June 2026 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 | Sleeping Adjacencies +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ / . / . / . Figure 2: Sleeping Adjacencies TLV Where: * Type: 1 octet, value TBD2 * Length: 1 octet, unsigned integer. The length of the TLV, measured in octets, not including the type and length fields. * Sleeping Adjacencies: A list of adjacency TLVs of type 22, 23, 141, 222 and 223. 3.3. Interface Extensions 3.3.1. The Power Group Member Sub-TLV This sub-TLV is found in TLVs for advertising neighbor information. This sub-TLV advertises a Power Group to which the interface belongs. Because a LAG interface can belong to many Power Groups, many instances of this sub-TLV may be advertised. 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 | Power Group Identifier +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Power Group Identifier (cont.)| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 3: Power Group Member Sub-TLV Where: * Type: 1 octet, value TBD3 * Length: 1 octet, unsigned integer. Value 4. * Power Group Identifier: 4 octets, selector. Barth, et al. Expires 24 December 2026 [Page 5] Internet-Draft IS-IS PG June 2026 3.3.2. The Interface PSP Sub-TLV This sub-TLV is found in TLVs for advertising neighbor information. This sub-TLV advertises an interface's PSP. 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 | PSP +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ PSP (cont.) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4: Interface Power Sub-TLV Where: * Type: 1 octet, value TBD4 * Length: 1 octet, unsigned integer. Value 4 * PSP: 4 octets, unsigned integer. The interface's PSP, in milliwatts. 3.3.3. Unidirectional Sleeping Bandwidth Sub-TLV This sub-TLV is found in TLVs for advertising neighbor information. This sub-TLV advertises the sleeping bandwidth. The sleeping bandwidth advertised by this sub-TLV MUST be the sleeping bandwidth from the system originating the Link State Advertisement (LSA) to its neighbor. 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 | Sleeping Bandwidth +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Sleeping Bandwidth | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5: Unidirectional Sleeping Bandwidth Sub-TLV Where: * Type: 1 octet, value TBD5 Barth, et al. Expires 24 December 2026 [Page 6] Internet-Draft IS-IS PG June 2026 * Length: 1 octet, unsigned integer. Value 4. * Sleeping Bandwidth: 4 octets, IEEE floating-point format measured in bytes per second. The Sleeping bandwidth field carries the sleeping bandwidth on a link, forwarding adjacency [RFC4206], or bundled link. For a link or forwarding adjacency, sleeping bandwidth is defined as the maximum bandwidth [RFC5305] minus the bandwidth currently allocated to RSVP- TE label switched paths that was transitioned to power-sleep. For a bundled link, sleeping bandwidth is defined to be the sum of the component link sleeping bandwidths. 3.3.4. The Power-Sleep Capable Bit This is a bit in the Link Attribute Sub-TLV (19). Presence of this bit indicates that the link may be put into power-sleep mode. The position of this bit is TBD5. 4. Security Considerations TBD 5. IANA Considerations IANA is requested to add the following entries to the IS-IS Top-Level TLV Codepoints registry (https://www.iana.org/assignments/isis-tlv- codepoints/isis-tlv-codepoints.xhtml#tlv-codepoints): +=======+=============+=====+=====+=====+=======+====+===========+ | Value | Name | IIH | LSP | SNP | Purge | MP | Status | | | | | | | | | Reference | +=======+=============+=====+=====+=====+=======+====+===========+ | TBD1 | Power Group | N | Y | N | N | N | This | | | | | | | | | document | +-------+-------------+-----+-----+-----+-------+----+-----------+ | TBD2 | Sleeping | N | Y | N | N | N | This | | | Adjacencies | | | | | | document | +-------+-------------+-----+-----+-----+-------+----+-----------+ Table 1: IS-IS Top-Level TLV Codepoints IANA is also requested to add the following entries to the IS-IS Sub- TLVs for TLVs Advertising Neighbor Information registry (https://www.iana.org/assignments/isis-tlv-codepoints/isis-tlv- codepoints.xhtml#isis-tlv-codepoints-advertising-neighbor- information): Barth, et al. Expires 24 December 2026 [Page 7] Internet-Draft IS-IS PG June 2026 +======+================+==+==+======+===+===+=====+==+===========+ | Type | Description |22|23| 25 |141|222| 223 |MP| Reference | +======+================+==+==+======+===+===+=====+==+===========+ | TBD3 | Power Group |Y |Y | Y(s) |Y |Y | Y |N | This | | | Member | | | | | | | | document | +------+----------------+--+--+------+---+---+-----+--+-----------+ | TBD4 | Interface PSP |Y |Y | Y(s) |Y |Y | Y |N | This | | | | | | | | | | | document | +------+----------------+--+--+------+---+---+-----+--+-----------+ | TBD5 | Unidirectional |Y |Y | Y(s) |Y |Y | Y |N | This | | | Sleeping | | | | | | | | document | | | Bandwith | | | | | | | | | +------+----------------+--+--+------+---+---+-----+--+-----------+ Table 2: IS-IS Sub-TLVs for TLVs Advertising Neighbor Information IANA is also requested to add the following entry to the IS-IS Neighbor Link-Attribute Bit Values registry (https://www.iana.org/assignments/isis-tlv-codepoints/isis-tlv- codepoints.xhtml#isis-tlv-codepoints-19of22): +=======+=====================+======+===============+ | Value | Name | L2BM | Reference | +=======+=====================+======+===============+ | TBD5 | Power-Sleep Capable | N | This document | +-------+---------------------+------+---------------+ Table 3: IS-IS Neighbor Link-Attribute Bit Values 6. Acknowledgements Thanks to Les Ginsberg for his review and comments. 7. Normative References [I-D.many-teas-power-steering] Barth, C., Li, T., Beeram, V. P., and R. P. Bonica, "A Power Conserving Path Placement Strategy (PCPPS)", Work in Progress, Internet-Draft, draft-many-teas-power-steering- 00, 21 February 2026, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . Barth, et al. Expires 24 December 2026 [Page 8] Internet-Draft IS-IS PG June 2026 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . Authors' Addresses Colby Barth HPE United States of America Email: Jonathan.barth@hpe.com Tony Li HPE United States of America Email: tony.li@tony.li Vishnu Pavan Beeram HPE United States of America Email: vbeeram@hpe.com Ron Bonica HPE United States of America Email: ronald.bonica@hpe.com Barth, et al. 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