]> Huawei

101 Software Avenue, Yuhua District Jiangsu 210012 China maqiufang1@huawei.com

Huawei

101 Software Avenue, Yuhua District Jiangsu 210012 China bill.wu@huawei.com

Orange

Rennes 35000 France mohamed.boucadair@orange.com

Lancaster University

United Kingdom d.king@lancaster.ac.uk

Operations and Management OPSAWG calendaring scheduling YANG groupings This document defines a common schedule YANG module which is designed to be applicable for scheduling information such as event, policy, services, or resources based on date and time. For the sake of better modularity, the module includes basic, intermediate, and advanced versions of schedule groupings.

Introduction Several specifications include a provision for scheduling. Examples of such specifications are (but not limited to) , , and . Both and use the "ietf-schedule" module initially specified in . Given that the applicability of the "ietf-schedule" module is more general than scheduled policy and OAM tests, this document defines "ietf-schedule" as a common schedule YANG module. The module includes a set of reusable groupings which are designed to be applicable for scheduling information such as event, policy, services or resources based on date and time. Examples to illustrate the use of the common groupings are provided in . Also, sample modules to exemplify how future modules can use the extensibility provisions in "ietf-schedule" are provided in .

Editorial Note (To be removed by RFC Editor) Note to the RFC Editor: This section is to be removed prior to publication. This document contains placeholder values that need to be replaced with finalized values at the time of publication. This note summarizes all of the substitutions that are needed. No other RFC Editor instructions are specified elsewhere in this document. Please apply the following replacements: XXXX --> the assigned RFC number for this draft YYYY --> the assigned RFC number for 2023-01-19 --> the actual date of the publication of this document

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 BCP 14 when, and only when, they appear in all capitals, as shown here. The meanings of the symbols in tree diagrams are defined in . Also, this document uses the YANG terminology defined in .

Module Overview The "ietf-schedule" module () defines the following groupings: period-of-time () recurrence () recurrence-with-date-times () icalendar-recurrence () provides an overview of the tree structure of the "ietf-schedule" module in terms of its groupings.

Each of these groupings is presented in the following subsections. Examples are provided in .

The "period-of-time" Grouping The "period-of-time" grouping () represents a time period using either a start ("period-start") and end date and time ("period-end"), or a start ("period-start") and a positive time duration ("duration"). For the first format, the start of the period MUST be before the end of the period (see ).

The "recurrence" Grouping The "recurrence" grouping () specifies a simple recurrence rule, the definition conforms to part of the "recurrence rule" properties in .

The "recurrence-first" container defines the first instance in the recurrence set. It also determines the start time and duration (if specified) of subsequent recurrence instances. If the "date-time-start" node is specified as a date-no-zone value type with no duration specified, the recurrence's duration is taken to be one day. The frequency ("frequency") identifies the type of recurrence rule. For example, a "daily" frequency value specifies repeating events based on an interval of a day or more. The interval represents at which intervals the recurrence rule repeats. For example, within a daily recurrence rule, an interval value of "8" means every eight days. The repetition can be scoped by a specified end time or by a count of occurrences, indicated by the "recurrence-bound" choice. The "date-time-start" value always counts as the first occurrence.

The "recurrence-with-date-times" Grouping The "recurrence-with-date-times" grouping () uses the "recurrence" grouping () and adds a "date-times-choice" statement to define an aggregate set of repeating occurrences.

The recurrence instances are defined by the union of occurrences defined by both date-times and recurrence rule. When duplicate instances are generated, only one recurrence is considered. Date-times definition inside "recurrence-with-date-times" grouping refers to but does not fully comply with . A timeticks type based period is added.

The "icalendar-recurrence" Grouping The "icalendar-recurrence" grouping () uses the "recurrence-with-date-times" grouping () and add more data nodes to enrich the definition of recurrence. The structure of the "icalendar-recurrence" grouping conforms to the definition of recurrence component defined in .

An array of the "bysecond" (or "byminut", "byhour") specifies a list of seconds within a minute (or minutes within an hour, hours of the day). The parameter "byday" specifies a list of days of the week, with an optional direction which indicates the nth occurrence of a specific day within the "monthly" or "yearly" frequency. For example, within a "monthly" rule, the "weekday" with a value of "monday" and the "direction" with a value of "-1" represents the last Monday of the month. An array of the "bymonthday" (or byyearday", "byyearweek", or "byyearmonth") specifies a list of days of the month (or days of the year, weeks of the year, or months of the year). The "bysetpos" conveys a list of values that corresponds to the nth occurrence within the set of recurrence instances to be specified. For example, in a "monthly" recurrence rule, the "byday" data node specifies every Monday of the week, the "bysetpos" with value of "-1" represents the last Monday of the month. Not setting the "bysetpos" data node represents every Monday of the month. The "workweek-start" data node specifies the day on which the week starts. This is significant when a "weekly" recurrence rule has an interval greater than 1, and a "byday" data node is specified. This is also significant when in a "yearly" rule and a "byyearweek" is specified. The default value is "monday". the "exception-dates" data node specifies a list of exceptions for recurrence. The final recurrence set is generated by gathering all of the date and time values generated by any of the specified recurrence rule and date-times, and then excluding any start date and time values specified by "exception-dates" parameter.

Features and Augmentations The "ietf-schedule" data model defines the recurrence related groupings using a modular approach. Basic, intermediate, and advanced representation of recurrence groupings are defined, with each reusing the previous one and adding more parameters. To allow for different options, two features are defined in the data model: 'basic-recurrence-supported' 'icalendar-recurrence-supported' provides an example about how that could be used. Implementations may support a basic recurrence rule or an advanced one as needed, by declaring different features. These groupings can also be augmented to support specific needs. As an example, demonstrates how additional parameters can be added to comply with specifc schedule needs.

The "ietf-schedule" YANG Module This module imports types defined in .

file "ietf-schedule@2023-01-19.yang" module ietf-schedule { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-schedule"; prefix schedule; import ietf-yang-types { prefix yang; revision-date 2023-01-23; reference "RFC YYYY: Common YANG Data Types"; } import ietf-system { prefix sys; reference "RFC 7317: A YANG Data Model for System Management"; } organization "IETF OPSAWG Working Group"; contact "WG Web: WG List: "; description "This YANG module defines two groupings for iCalendar (Internet Calendaring and Scheduling Core Object Specification) data types: period of time and recurrence rule, for representing and exchanging calendaring and scheduling information. The YANG module complies with Sections 3.3.9 and 3.3.10 of RFC 5545. Copyright (c) 2023 IETF Trust and the persons identified as authors of the code. All rights reserved. Redistribution and use in source and binary forms, with or without modification, is permitted pursuant to, and subject to the license terms contained in, the Revised BSD License set forth in Section 4.c of the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info). This version of this YANG module is part of RFC XXXX (https://www.rfc-editor.org/info/rfcXXXX); see the RFC itself for full legal notices. 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 BCP 14 (RFC 2119) (RFC 8174) when, and only when, they appear in all capitals, as shown here."; revision 2023-01-19 { description "Initial revision."; reference "RFC XXXX: A YANG Data Model for Scheduling."; } feature basic-recurrence-supported { description "Indicates that the server supports configuring a basic scheduled recurrence."; } feature icalendar-recurrence-supported { description "Indicates that the server supports configuring a comprehensive scheduled icalendar recurrence"; reference "RFC 5545: Internet Calendaring and Scheduling Core Object Specification (iCalendar), Section 3.3.10 and 3.8.5"; } typedef weekday { type enumeration { enum sunday { value 0; description "Sunday of the week."; } enum monday { value 1; description "Monday of the week."; } enum tuesday { value 2; description "Tuesday of the week."; } enum wednesday { value 3; description "Wednesday of the week."; } enum thursday { value 4; description "Thursday of the week."; } enum friday { value 5; description "Friday of the week."; } enum saturday { value 6; description "Saturday of the week."; } } description "Seven days of the week."; } typedef duration { type string { pattern '((\+)?|\-)P((([0-9]+)D)?(T(0[0-9]|1[0-9]|2[0-3])' + ':[0-5][0-9]:[0-5][0-9]))|P([0-9]+)W'; } description "Duration of the time. The format can represent nominal durations (weeks designated by 'W' and days designated by 'D') and accurate durations (hours:minutes:seconds follows the designator 'T'). Note that this value type doesn't support the 'Y' and 'M' designators to specify durations in terms of years and months. Negative durations are typically used to schedule an alarm to trigger before an associated time."; reference "RFC 5545: Internet Calendaring and Scheduling Core Object Specification (iCalendar), Sections 3.3.6 and 3.8.6.3"; } identity frequency-type { description "Base identity for frequency type."; } identity secondly { base frequency-type; description "Identity for a repeating event based on an interval of a second or more."; } identity minutely { base frequency-type; description "Identity for a repeating event based on an interval of a minute or more."; } identity hourly { base frequency-type; description "Identity for a repeating event based on an interval of an hour or more."; } identity daily { base frequency-type; description "Identity for a repeating event based on an interval of a day or more."; } identity weekly { base frequency-type; description "Identity for a repeating event based on an interval of a week or more."; } identity monthly { base frequency-type; description "Identity for a repeating event based on an interval of a month or more."; } identity yearly { base frequency-type; description "Identity for a repeating event based on an interval of a year or more."; } grouping period-of-time { description "This grouping is defined for period of time property."; reference "RFC 5545: Internet Calendaring and Scheduling Core Object Specification (iCalendar), Section 3.3.9"; leaf period-start { type yang:date-and-time; description "Period start time."; } leaf time-zone-identifier { type sys:timezone-name; description "Indicates the identifier for the time zone in a time zone database. This parameter MUST be specified if 'period-start' value is neither reported in the format of UTC nor time zone offset to UTC."; } choice period-type { description "Indicates the type of the time period. Two types are supported."; case explicit { description "A period of time is identified by its start and its end. 'period-start' indicates the period start."; leaf period-end { type yang:date-and-time; description "Period end time. The start MUST be before the end. If a local time without time zone offset to UTC time is specified, it MUST use the same time zone reference as 'period-start' parameter. If 'period-start' also uses a local time without time zone offset to UTC, it MUST use the time zone as specified by the 'time-zone-identifier' parameter."; } } case duration { description "A period of time is defined by a start and a positive duration of time."; leaf duration { type duration { pattern 'P((([0-9]+)D)?(T(0[0-9]|1[0-9]|2[0-3])' + ':[0-5][0-9]:[0-5][0-9]))|P([0-9]+)W'; } description "A positive duration of the time. This value is equivalent to the format of duration type except that the value cannot be negative."; } } } } grouping recurrence { description "A simple definition of recurrence."; container recurrence-first { description "Specifies the first instance of the recurrence."; leaf date-time-start { type union { type yang:date-no-zone; type yang:date-and-time; } description "Defines the first instance in the recurrence set. If it is specified as a date-no-zone value type with no duration specified, the recurrence's duration is taken to be one day."; reference "RFC 5545: Internet Calendaring and Scheduling Core Object Specification (iCalendar), Section 3.3.10"; } leaf time-zone-identifier { type sys:timezone-name; description "Indicates the identifier for the time zone in a time zone database. This parameter MUST be specified if 'start' value is neither reported in the format of UTC nor time zone offset to UTC."; } leaf duration { type duration; description "When specified, it refers to the duration of the first occurrence. The exact duration also applies to all the recurrence instance."; } } leaf frequency { type identityref { base frequency-type; } description "This parameter is defined to identify the frequency type of the recurrence rule."; } leaf interval { type uint32; description "A positive integer representing at which intervals the recurrence rule repeats. For example, within a 'daily' recurrence rule, a value of '8' means every eight days."; } choice recurrence-bound { description "Modes to bound the recurrence rule. If no choice is indicated, the recurrence rule is considered to repeat forever."; case until { description "This case defines a way that bounds the recurrence rule in an inclusive manner."; leaf until { type union { type yang:date-no-zone; type yang:date-and-time; } description "This parameter specifies a date-no-zone or date-time value to bounds the recurrence. If the value specified by this parameter is synchronized with the specified recurrence, it becomes the last instance of the recurrence. The value MUST have the same value type as the value type of 'start' parameter."; } } case count { description "This case defines the number of occurrences at which to range-bound the recurrence."; leaf count { type uint32; description "The positive number of occurrences at which to range-bound the recurrence."; } } } } grouping recurrence-with-date-times { description "This grouping defines an aggregate set of repeating occurrences. The recurrence instances are defined by the union of occurrences defined by both the 'recurrence' and 'date-times'. Duplicate instances are ignored."; uses recurrence; choice date-times-choice { description "Specify a list of occurrences which complement the recurrence set defined by 'recurrence' grouping. If it is specified as a period value, the duration of the recurrence instance will be the one specified by it, and not the duration defined inside the recurrence-first parameter."; case date-time { description "Specify a list of occurrences with date-and-time values."; leaf-list date-times { type yang:date-and-time; description "Specifies a set of date-and-time values of occurrences."; } } case date { description "Specifies a list of occurrences with date-no-zone values."; leaf-list dates { type yang:date-no-zone; description "Specifies a set of date-no-zone values of occurrences."; } } case period-timeticks { description "Specifies a list of occurrences with period span of timeticks format."; list period-timeticks { key "period-start"; description "A list of period with timeticks formats."; leaf period-start { type yang:timeticks; must "(not(derived-from(../../frequency," +"'schedule:secondly')) or (current() < 100)) and " +"(not(derived-from(../../frequency," +"'schedule:minutely')) or (current() < 6000)) and " +"(not(derived-from(../../frequency,'schedule:hourly'))" +" or (current() < 360000)) and " +"(not(derived-from(../../frequency,'schedule:daily'))" +" or (current() < 8640000)) and " +"(not(derived-from(../../frequency,'schedule:weekly'))" +" or (current() < 60480000)) and " +"(not(derived-from(../../frequency," +"'schedule:monthly')) or (current() < 267840000)) and " +"(not(derived-from(../../frequency,'schedule:yearly'))" +" or (current() < 3162240000))" { error-message "The period-start must not exceed the frequency interval."; } description "Start time of the scheduled value within one recurrence."; } leaf period-end { type yang:timeticks; description "End time of the scheduled value within one recurrence."; } } } case period { description "Specifies a list of occurrences with period span of date-and -time format."; list period { key "period-start"; description "A list of period with date-and-time formats."; uses period-of-time; } } } } grouping icalendar-recurrence { description "This grouping is defined to identify properties that contain a recurrence rule."; reference "RFC 5545: Internet Calendaring and Scheduling Core Object Specification (iCalendar), Section 3.8.5"; uses recurrence-with-date-times; leaf-list bysecond { type uint32 { range "0..60"; } description "A list of seconds within a minute."; } leaf-list byminute { type uint32 { range "0..59"; } description "A list of minutes within an hour."; } leaf-list byhour { type uint32 { range "0..23"; } description "Specifies a list of hours of the day."; } list byday { key "weekday"; description "Specifies a list of days of the week."; leaf-list direction { when "derived-from(../../frequency, 'schedule:monthly') or " + "(derived-from(../../frequency, 'schedule:yearly') " + " and not(../../byyearweek))"; type int32 { range "-53..-1|1..53"; } description "When specified, it indicates the nth occurrence of a specific day within the monthly or yearly recurrence rule. For example, within a monthly rule, +1 monday represents the first monday within the month, whereas -1 monday represents the last monday of the month."; } leaf weekday { type schedule:weekday; description "Corredponds to seven days of the week."; } } leaf-list bymonthday { type int32 { range "-31..-1|1..31"; } description "Specifies a list of days of the month."; } leaf-list byyearday { type int32 { range "-366..-1|1..366"; } description "Specifies a list of days of the year."; } leaf-list byyearweek { when "derived-from(../frequency, 'schedule:yearly')"; type int32 { range "-53..-1|1..53"; } description "Specifies a list of weeks of the year."; } leaf-list byyearmonth { type uint32 { range "1..12"; } description "Specifies a list of months of the year."; } leaf-list bysetpos { type int32 { range "-366..-1|1..366"; } description "Specifies a list of values that corresponds to the nth occurrence within the set of recurrence instances specified by the rule. It must only be used in conjunction with another by the rule part."; } leaf workweek-start { type schedule:weekday; default "monday"; description "Specifies the day on which the workweek starts."; } leaf-list exception-dates { type union { type yang:date-no-zone; type yang:date-and-time; } description "Defines a list of exceptions for recurrence."; } } } ]]>

Security Considerations The "ietf-schedule" YANG module specified in this document defines schema for data that is designed to be accessed via network management protocols such as NETCONF or RESTCONF . The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH) . The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS . The Network Configuration Access Control Model (NACM) provides the means to restrict access for particular NETCONF or RESTCONF users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. The "ietf-schedule" module defines a set of types and groupings. These nodes are intended to be reused by other YANG modules. The module by itself does not expose any data nodes that are writable, data nodes that contain read-only state, or RPCs. As such, there are no additional security issues related to the "ietf- schedule" module that need to be considered.

IANA Considerations

The "IETF XML" Registry This document registers the following URI in the "IETF XML Registry" .

The "YANG Module Names" Registry This document registers the following YANG module in the "YANG Module Names" registry .

In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. YANG is a data modeling language used to model configuration data, state data, Remote Procedure Calls, and notifications for network management protocols. This document describes the syntax and semantics of version 1.1 of the YANG language. YANG version 1.1 is a maintenance release of the YANG language, addressing ambiguities and defects in the original specification. There are a small number of backward incompatibilities from YANG version 1. This document also specifies the YANG mappings to the Network Configuration Protocol (NETCONF). This document defines the iCalendar data format for representing and exchanging calendaring and scheduling information such as events, to-dos, journal entries, and free/busy information, independent of any particular calendar service or protocol. [STANDARDS-TRACK] Constructor University This document defines a collection of common data types to be used with the YANG data modeling language. This version of the document adds several new type definitions and obsoletes RFC 6991. The Network Configuration Protocol (NETCONF) defined in this document provides mechanisms to install, manipulate, and delete the configuration of network devices. It uses an Extensible Markup Language (XML)-based data encoding for the configuration data as well as the protocol messages. The NETCONF protocol operations are realized as remote procedure calls (RPCs). This document obsoletes RFC 4741. [STANDARDS-TRACK] This document describes an HTTP-based protocol that provides a programmatic interface for accessing data defined in YANG, using the datastore concepts defined in the Network Configuration Protocol (NETCONF). This document describes a method for invoking and running the Network Configuration Protocol (NETCONF) within a Secure Shell (SSH) session as an SSH subsystem. This document obsoletes RFC 4742. [STANDARDS-TRACK] This document specifies version 1.3 of the Transport Layer Security (TLS) protocol. TLS allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery. This document updates RFCs 5705 and 6066, and obsoletes RFCs 5077, 5246, and 6961. This document also specifies new requirements for TLS 1.2 implementations. The standardization of network configuration interfaces for use with the Network Configuration Protocol (NETCONF) or the RESTCONF protocol requires a structured and secure operating environment that promotes human usability and multi-vendor interoperability. There is a need for standard mechanisms to restrict NETCONF or RESTCONF protocol access for particular users to a preconfigured subset of all available NETCONF or RESTCONF protocol operations and content. This document defines such an access control model. This document obsoletes RFC 6536. This document describes an IANA maintained registry for IETF standards which use Extensible Markup Language (XML) related items such as Namespaces, Document Type Declarations (DTDs), Schemas, and Resource Description Framework (RDF) Schemas. YANG is a data modeling language used to model configuration and state data manipulated by the Network Configuration Protocol (NETCONF), NETCONF remote procedure calls, and NETCONF notifications. [STANDARDS-TRACK] Huawei Huawei Orange Lancaster University This document defines a YANG data model for policy-based network access control, which provides consistent and efficient enforcement of network access control policies based on group identity. Moreover, this document defines a mechanism to ease the maintenance of the mapping between a user group identifier and a set of IP/MAC addresses to enforce policy-based network access control. In addition, the document defines a RADIUS attribute that is used to communicate the user group identifier as part of identification and authorization information. Telefonica Nokia This document defines a YANG data model for network diagnosis on- demand using Operations, Administration, and Maintenance (OAM) tests. This document defines both 'oam-unitary-test' and 'oam-test-sequence' data models to enable on-demand activation of network diagnosis procedures. Futurewei LabN Consulting, L.L.C. LabN Consulting, L.L.C. LabN Consulting, L.L.C. Viagenie The YANG model in this document includes three modules, and can be used to manage network resources and topologies with scheduled attributes, such as predictable link loss and link connectivity as a function of time. The intent is to have this information be utilized by Time-Variant Routing systems. This document captures the current syntax used in YANG module tree diagrams. The purpose of this document is to provide a single location for this definition. This syntax may be updated from time to time based on the evolution of the YANG language. This document defines encoding rules for representing configuration data, state data, parameters of Remote Procedure Call (RPC) operations or actions, and notifications defined using YANG as JavaScript Object Notation (JSON) text. JHU/APL Thales Alenia Space Futurewei Technologies Ori Industries Huawei This document introduces use cases where Time-Variant Routing (TVR) computations (i.e. routing computations taking into considerations time-based or scheduled changes to a network) could improve routing protocol convergence and/or network performance. Huawei Individual Fraunhofer SIT Volta Networks Cisco This document defines a YANG data model for Event Condition Action (ECA) policy management. The ECA policy YANG module provides the ability to delegate some network management functions to the server (e.g., a NETCONF or RESTCONF server) which can take simple and instant action when a trigger condition on the managed objects is met.

Examples of Format Representation This section provides some examples to illustrate the use of the period and recurrence formats defined as YANG groupings. Note that "grouping" does not define any data nodes in the schema tree, the examples illustrated are just for the ease of understanding. Only the message body is provided with JSON used for encoding .

The "period-of-time" Grouping The example of a period that starts at 08:00:00 UTC, on January 1, 2025 and ends at 18:00:00 UTC on December 31, 2027 is encoded as shown in .

An example of a period that starts at 08:00:00 UTC, on January 1, 2025 and lasts 15 days and 5 hours and 20 minutes is encoded as shown in .

An example of a period that starts at 2:00 A.M. in Los Angeles on November 19, 2025 and lasts 20 weeks is depicted in .

The "recurrence" Grouping indicates a recurrence of every 2 days for 10 occurrences, starting at 3 p.m. on December 1, 2025 in the Eastern United States time zone:

illustrates an example of an anniversary that will occur annually, from 1997-11-25, until 2050-11-25:

The "recurrence-with-date-times" Grouping indicates a recurrence that occurs every 2 hours from 9:00 AM to 5:00 PM, and 6PM UTC time on 2025-12-01:

indicates a recurrence that occurs every 30 minutes and last for 15 minutes from 9:00 AM to 5:00 PM, and extra two occurrences at 6:00 PM and 6:30 PM with each lasting for 20 minutes on 2025-12-01:

The "icalendar-recurrence" Grouping indicates 10 occurrences that occur at 8:00 AM (EST), every last Saturday of the month starting in January 2024:

is an example of a recurrence that occurs on the last workday of the month until December 25, 2024, from January 1, 2024:

indicates a recurrence that occur every 20 minutes from 9:00 AM to 4:40 PM (UTC), with the occurrence starting at 10:20 AM being excluded on 2025-12-01:

Examples of Using/Extending the "ietf-schedule" Module This non-normative section shows two examples for how the "ietf-schedule" module can be used or extended for scheduled events or attributes based on date and time.

Example: Schedule Tasks to Execute Based on a Recurrence Rule Scheduled tasks can be used to execute specific actions based on certain recurrence rules (e.g., every Friday at 8:00 AM). The following example module which "uses" the "icalendar-recurrence" grouping from "ietf-schedule" module shows how a scheduled task could be defined with different features used for options.

Example: Schedule Network Properties to Change Based on Date and Time Network properties may change over a specific period of time or based on a recurrence rule, e.g., . The following example module which augments the "recurrence-with-date-times" grouping from "ietf-schedule" module shows how a scheduled based attribute could be defined.

shows a configuration example of a link's bandwidth that is scheduled between 2023/12/01 0:00 UTC to the end of 2023/12/31 with a daily schedule. In each day, the bandwidth value is scheduled to be 500 Kbps between 1:00 AM to 6:00 AM and 800 Kbps between 10:00 PM to 11:00 PM. The bandwidth value that's not covered by the period above is 1000 Kbps by default.

ne1 ne2 1000 2023-12-01T01:00:00Z schedule:daily 2023-12-31T23:59:59Z 360000 2160000 500 7920000 8280000 800 ]]>

Acknowledgments This work is derived from the . There is a desire from the OPSAWG to see this model be separately defined for wide use in scheduling context. Thanks to Adrian Farrel, Wei Pan, Tianran Zhou, and Joe Clarke for their valuable comments and inputs to this work. Many thanks to the authors of , , and for the constructive discussion during IETF#118.