netmod
Internet Engineering Task Force (IETF) Q. Ma, Ed.
Internet-Draft
Request for Comments: 9922 Q. Wu
Intended status:
Category: Standards Track Huawei
Expires: 8 February 2026
ISSN: 2070-1721 M. Boucadair, Ed.
Orange
D. King
Lancaster University
7 August 2025
February 2026
A Common YANG Data Model for Scheduling
draft-ietf-netmod-schedule-yang-10
Abstract
This document defines common types and groupings that are meant to be
used for scheduling purposes purposes, such as event, policy, events, policies, services, or
resources based on date and time. For the sake of better modularity,
the YANG module includes a set of recurrence-related groupings with
varying levels of representation (i.e., from basic to advanced) to
accommodate a variety of requirements. It also defines groupings for
validating requested schedules and reporting scheduling status.
Discussion Venues
This note is to be removed before publishing as an RFC.
Discussion of this document takes place on the Network Modeling
(NETMOD) Working Group mailing list (netmod@ietf.org), which is
archived at https://mailarchive.ietf.org/arch/browse/netmod/.
Source for this draft and an issue tracker can be found at
https://github.com/netmod-wg/schedule-yang. statuses.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Editorial Note (To be removed by RFC Editor) . . . . . . 4
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 4
3. Module Overview . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Features . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. Types and Identities . . . . . . . . . . . . . . . . . . 5
3.3. Scheduling Groupings . . . . . . . . . . . . . . . . . . 6
3.3.1. The "generic-schedule-params" Grouping . . . . . . . 7
3.3.2. The "period-of-time" Grouping . . . . . . . . . . . . 8
3.3.3. The "recurrence-basic" Grouping . . . . . . . . . . . 9
3.3.4. The "recurrence-utc" Grouping . . . . . . . . . . . . 9
3.3.5. The "recurrence-with-time-zone" Grouping . . . . . . 11
3.3.6. The "recurrence-utc-with-periods" Grouping . . . . . 12
3.3.7. The "recurrence-time-zone-with-periods" Grouping . . 12
3.3.8. The "icalendar-recurrence" Grouping . . . . . . . . . 13
3.3.9. The "schedule-status",
"schedule-status-with-time-zone", and
"schedule-status-with-name" Groupings . . . . . . . . 16
3.4. Features Use and Augmentations . . . . . . . . . . . . . 18
4. Some Usage Restrictions . . . . . . . . . . . . . . . . . . . 18
5. Relationship to the DISMAN-SCHEDULE-MIB . . . . . . . . . . . 19
6. The "ietf-schedule" YANG Module . . . . . . . . . . . . . . . 21
7. Security Considerations . . . . . . . . . . . . . . . . . . . 39
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 40
8.1. The "IETF XML" IETF XML Registry . . . . . . . . . . . . . . . . . 40
8.2. The "YANG YANG Module Names" Names Registry . . . . . . . . . . . . 40
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 40
9.1. Normative References . . . . . . . . . . . . . . . . . . 40
9.2. Informative References . . . . . . . . . . . . . . . . . 41
Appendix A. Examples of Scheduling Format Representation . . . . 43
A.1. The "generic-schedule-params" Grouping . . . . . . . . . 46
A.2. The "period-of-time" Grouping . . . . . . . . . . . . . . 47
A.3. The "recurrence-basic" Grouping . . . . . . . . . . . . . 48
A.4. The "recurrence-utc" Grouping . . . . . . . . . . . . . . 48
A.5. The "recurrence-with-time-zone" Grouping . . . . . . . . 49
A.6. The "recurrence-utc-with-periods" Grouping . . . . . . . 49
A.7. The "recurrence-time-zone-with-periods" Grouping . . . . 50
A.8. The "icalendar-recurrence" Grouping . . . . . . . . . . . 50
A.9. The "schedule-status" Grouping . . . . . . . . . . . . . 53
Appendix B. Examples of Using/Extending the "ietf-schedule" Module . . . . . . . . . . . . . . . . . . . . . . . . . 54
B.1. Example: Schedule Tasks to Execute Based on a Recurrence
Rule . . . . . . . . . . . . . . . . . . . . . . . . . . 54
B.2. Example: Schedule Network Properties to Change Based on
Date and Time . . . . . . . . . . . . . . . . . . . . . . 57
Appendix C. Examples of Using the "ietf-schedule" Module for
Scheduled Use of Resources Framework . . . . . . . . . . . . . . . 60
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 61
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 62
1. Introduction
This document defines a common schedule YANG module ("ietf-schedule")
that can be used in several scheduling contexts, e.g., (but not
limited to) [I-D.ietf-opsawg-ucl-acl],
[I-D.ietf-opsawg-scheduling-oam-tests], [YANG-NAC], [YANG-OAM], and
[I-D.ietf-tvr-schedule-yang]. [YANG-SCHEDULE]. The module
includes a set of reusable groupings which that are designed to be
applicable for scheduling purposes purposes, such as event, policy, services events, policies,
services, or resources based on date and time. It also defines
groupings for validating requested schedules and reporting scheduling status.
statuses.
This document does not make any assumption about the nature of
actions that are triggered by the schedules. Detection and
resolution of any schedule conflicts are beyond the scope of this
document.
Section 5 discusses the relationship with the Management Information
Base (MIB) managed objects for scheduling management operations
defined in [RFC3231].
Appendix A describes a set of examples to illustrate the use of the
common schedule groupings (Section 3.3). Appendix B provides sample
modules to exemplify how future modules can use the extensibility
provisions in the "ietf-schedule" module (Section 6). Also,
Appendix C provides an example of using the "ietf-schedule" module
for scheduled use of a resources framework (e.g., [RFC8413]).
1.1. 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
* 2025-05-30 --> the actual date of the publication of this document
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
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
The meanings of the symbols in tree diagrams are defined in
[RFC8340].
This document uses the YANG terminology defined in Section 3 of
[RFC7950].
The
This document makes use of the following terms:
Recurrence rule: Refers to a rule or repeating pattern for recurring
events. See also Section 3.8.5.3 of [RFC5545] for a comprehensive
iCalendar recurrence rule specification.
Recurrence instance (or Recurrence, for short): Refers to an
instance that matches a recurrence rule.
Recurrence set: Refers to a set of recurrence instances.
Frequency: Characterizes the type of a recurrence rule. Values are
taken from the "FREQ" rule in Section 3.3.10 of [RFC5545].
For example, repeating events based on an interval of a second or
more are classified as recurrence with a frequency value of
"SECONDLY". Frequency values defined as identities in the YANG
module are used in lowercase.
iCalendar: Refers to Internet Calendaring per [RFC5545].
Interval: Refers to an integer that specifies the interval at which
a recurrence rule repeats. Values are taken from the "INTERVAL"
rule in Section 3.3.10 of [RFC5545].
For example, "1", "1" means every second for a secondly rule, every
minute for a minutely rule, every hour for an hourly rule, etc.
System: Refers to an entity that hosts a schedule that is managed
using the YANG module defined in this document.
3. Module Overview
3.1. Features
The "ietf-schedule" data model defines the recurrence related recurrence-related
groupings using a modular approach. To that aim, a variety of
representations of recurrence groupings ranging from basic to
advanced (iCalender-like) are defined. To allow for different
options, two features are defined in the data model:
* "basic-recurrence"
* "icalendar-recurrence"
Refer to Sections Section 3.4 and Appendix B.1 for the use of these features.
3.2. Types and Identities
The "ietf-schedule" module (Section 6) defines the following
identities:
* "schedule-type": Indicates the type of a schedule. The following
types are defined so far:
- one-shot: The schedule will trigger an action that has either
the duration specified as 0 or the end time specified as the
same as the start time, and then the schedule will disable
itself (Section 3.3 of [RFC3231]).
- period: The schedule This type is used for a period-based schedule
consisting of either (1) a start and end or (2) a start and
positive duration of time. If neither an end nor a duration is
indicated, the period is considered to last forever.
- recurrence: This type is used for a recurrence-based schedule.
A recurrence may be periodic (i.e., repeat over the same
period, e.g., every five minutes) or not (i.e., repeat in a
non-regular manner, e.g., every day at 8 and 9 AM).
* "frequency-type": Characterizes the repeating interval rule of a
recurrence schedule (secondly, minutely, etc.).
* "schedule-state": Indicates the status of a schedule (enabled,
disabled, conflicted, finished, etc.). This identity can also be
used to manage the state of individual instances of a recurrence-
based schedule.
* "discard-action-type": Specifies the action for the responder to
take (e.g., generate a warning or an error message) when a
requested schedule cannot be accepted for any reason and is
discarded.
3.3. Scheduling Groupings
The "ietf-schedule" module (Section 6) defines the following
groupings:
* "generic-schedule-params" (Section 3.3.1)
* "period-of-time" (Section 3.3.2)
* "recurrence-basic" (Section 3.3.3)
* "recurrence-utc" (Section 3.3.4)
* "recurrence-with-time-zone" (Section 3.3.5)
* "recurrence-utc-with-periods" (Section 3.3.6)
* "recurrence-time-zone-with-periods" (Section 3.3.7)
* "icalendar-recurrence" (Section 3.3.8)
* "schedule-status", "schedule-status-with-time-zone", and
"schedule-status-with-name" (Section 3.3.9)
Examples are provided in Appendix A.
3.3.1. The "generic-schedule-params" Grouping
A system accepts and handles schedule requests, which may help
further automate the scheduling process of events, policy, policies,
services, or resources based on date and time. The "generic-schedule-params" "generic-
schedule-params" grouping (Figure 1) specifies a set of configuration
parameters that are used by a system for validating requested
schedules.
grouping generic-schedule-params:
+-- description? string
+-- time-zone-identifier? sys:timezone-name
+-- validity? yang:date-and-time
+-- max-allowed-start? yang:date-and-time
+-- min-allowed-start? yang:date-and-time
+-- max-allowed-end? yang:date-and-time
+-- discard-action? identityref
Figure 1: 'generic-schedule-params' Grouping Tree Structure
The "description" parameter includes a description of the schedule.
No constraint is imposed on the structure nor the use of this
parameter.
The "time-zone-identifier" parameter, if provided, specifies the time
zone reference [RFC7317] of the local date and time values. This
parameter MUST be specified if any of the date and time values are in
the format of local time. It MUST NOT be applied to date and time
values which that are specified in the format of UTC or time zone offset to
UTC.
The "validity" parameter specifies the date and time after which a
schedule will not be considered as valid. It determines the latest
time that a schedule can be started to execute independent of when it
ends
ends, and it takes precedence over similar attributes that are
provided at the schedule instance itself. A requested schedule may
still be
accepted accepted, but any occurrences that start later than the
configured value will not be executed.
The "max/min-allowed-start" parameters specify the maximum/minimum
scheduled start date and time. A requested schedule will be rejected
if the first occurrence of the schedule starts later/earlier than the
configured values.
The "max-allowed-end" parameter specifies the maximum allowed end
time of the last occurrence. A requested schedule will be rejected
if the end time of the last occurrence is later than the configured "max-
allowed-end"
"max-allowed-end" value.
The "discard-action" parameter specifies the action if a requested
schedule cannot be accepted for any reason and is discarded.
Possible reasons include, but are not limited to, the requested
schedule failing to satisfy the guards in this grouping, conflicting
with existing schedules, or being out-of-date (e.g., the expected
start is has already passed).
*
These parameters apply to all schedules on a system and are meant to
provide guards against stale configuration, too short schedule
requests that would prevent validation by admins of some critical
systems, etc.
3.3.2. The "period-of-time" Grouping
The "period-of-time" grouping (Figure 2) represents a time period
using either a start date and time ("period-start") and end date and
time ("period-end"), ("period-end") or a start date and time ("period-start") and a
non-negative time duration ("duration"). For the first format, the
start of the period MUST be no later than the end of the period. If
neither an end date and time ("period-end") nor a duration
("duration") is indicated, the period is considered to last forever.
If the duration ("duration") value is 0 or the end time ("period-
end") is the same as the start time ("period-start"), the period is
considered as a one-shot schedule. If no start date and time
("period-start") is specified, the period is considered to start
immediately.
The "time-zone-identifier" parameter indicates the identifier for the
time zone. This parameter MUST be specified if either the "period-
start" or "period-end" value is reported in local time format. It
MUST NOT be applied to date and time values which that are specified in the
format of UTC or time zone offset to UTC.
The "period-description" parameter includes a description of the
period. No constraint is imposed on the structure nor the use of
this parameter.
grouping period-of-time:
+-- period-description? string
+-- period-start? yang:date-and-time
+-- time-zone-identifier? sys:timezone-name
+-- (period-type)?
+--:(explicit)
| +-- period-end? yang:date-and-time
+--:(duration)
+-- duration? duration
Figure 2: 'period-of-time' Grouping Tree Structure
3.3.3. The "recurrence-basic" Grouping
The "recurrence-basic" grouping (Figure 3) specifies a simple
recurrence rule which that starts immediately and repeats forever.
grouping recurrence-basic:
+-- recurrence-description? string
+-- frequency? identityref
+-- interval? uint32
Figure 3: 'recurrence-basic' Grouping Tree Structure
The frequency parameter ("frequency") identifies the type of a
recurrence rule. For example, a "daily" frequency value specifies
repeating events based on an interval of a day or more.
Consistent with Section 3.3.10 of [RFC5545], the interval parameter
("interval") represents at which interval the recurrence rule
repeats. For example, within a "daily" recurrence rule, an interval
value of "8" means every eight days.
Note that that, per Section 4.13 of [I-D.ietf-netmod-rfc8407bis], [YANG-GUIDE], neither a "default" nor
a "mandatory" substatement is defined here for both "frequency" and
"interval" parameters because there are cases (e.g., profiling) where
using these statements is problematic. YANG modules using this
grouping SHOULD refine these two nodes with either a "mandatory" or a
"default" statement, statement if they always need to be configured or have
default values. This recommendation MAY be ignored in cases such as
when this grouping is used by another grouping.
The "recurrence-description" parameter includes a description of the
period. No constraint is imposed on the structure nor the use of
this parameter.
3.3.4. The "recurrence-utc" Grouping
The "recurrence-utc" grouping (Figure 4) uses the "recurrence-basic"
grouping (Section 3.3.3) and specifies a simple recurrence rule in
UTC format.
grouping recurrence-utc:
+-- recurrence-first
| +-- start-time-utc? yang:date-and-time
| +-- duration? uint32
+-- (recurrence-end)?
| +--:(until)
| | +-- utc-until? yang:date-and-time
| +--:(count)
| +-- count? uint32
+-- recurrence-description? string
+-- frequency? identityref
+-- interval? uint32
Figure 4: 'recurrence-utc' Grouping Tree Structure
The "start-time-utc" parameter indicates the start time in UTC
format.
The "duration" parameter specifies, in units of seconds, the time
period of the first occurrence. Unless specified otherwise (e.g.,
through additional augmented parameters), the "duration" also applies
to subsequent recurrence instances. When unspecified, each
occurrence is considered as immediate completion (e.g., execute an
immediate command that is considered to complete quickly) or hard to
compute an exact duration (e.g., run a data analysis script whose
execution time may depend on the data volume and computation resource
availability). The behavior to follow when a task takes more time
than specified by the "duration" is out of scope. Such
considerations belong to task management, not schedule management.
Note that the "interval" and "duration" cover two distinct properties
of a schedule event. The interval specifies when a schedule will
occur, combined with the frequency parameter; parameter, while the duration
indicates how long an occurrence will last. This document allows the
interval between occurrences to be shorter than the duration of each
occurrence (e.g., a recurring event is scheduled to start every day
for a duration of 2 days).
The repetition can be scoped by a specified end time or by a count of
occurrences, indicated by the "recurrence-end" choice. The "count"
value MUST be greater than 1, and the "start-time-utc" value always
counts as the first occurrence.
The "recurrence-utc" grouping is designed to be reused in scheduling
contexts where machine readability is more desirable.
3.3.5. The "recurrence-with-time-zone" Grouping
The "recurrence-with-time-zone" grouping (Figure 5) uses the
"recurrence-basic" grouping (Section 3.3.3) and specifies a simple
recurrence rule with a time zone.
grouping recurrence-with-time-zone:
+-- recurrence-first
| +-- start-time? yang:date-and-time
| +-- duration? duration
+-- time-zone-identifier? sys:timezone-name
+-- (recurrence-end)?
| +--:(until)
| | +-- until? yang:date-and-time
| +--:(count)
| +-- count? uint32
+-- recurrence-description? string
+-- frequency? identityref
+-- interval? uint32
Figure 5: 'recurrence-with-time-zone' Grouping Tree Structure
The "recurrence-first" container includes "start-time" and "duration"
parameters to specify the start time and period of the first
occurrence. Unless specified otherwise (e.g., through additional
augmented parameters), the "duration" also applies to subsequent
recurrence instances. When unspecified, each occurrence is
considered as immediate completion (e.g., execute an immediate
command that is considered to complete quickly) or hard to compute an
exact duration (e.g., run a data analysis script whose execution time
may depend on the data volume and computation resource availability).
The grouping also includes a "time-zone-identifier" parameter parameter, which
MUST be specified if either the "start-time" or "until" value is
reported in local time format. It MUST NOT be applied to date and
time values which that are specified in the format of UTC or time zone
offset to UTC.
The repetition can be scoped by a specified end time or by a count of
occurrences, indicated by the "recurrence-end" choice. The "count"
value MUST be greater than 1, and the "start-time" value always
counts as the first occurrence.
The considerations discussed in Section 3.3.4 for "interval" and
"duration" are also applicable to "recurrence-with-time-zone".
Unlike the definition of the "recurrence-utc" grouping
(Section 3.3.4), "recurrence-with-time-zone" is intended to promote
human readability over machine readability.
3.3.6. The "recurrence-utc-with-periods" Grouping
The "recurrence-utc-with-periods" grouping (Figure 6) uses the
"recurrence-utc" grouping (Section 3.3.4) and adds a "period-
timeticks" list to define an aggregate set of repeating occurrences.
grouping recurrence-utc-with-periods:
+-- recurrence-first
| +-- start-time-utc? yang:date-and-time
| +-- duration? uint32
+-- (recurrence-end)?
| +--:(until)
| | +-- utc-until? yang:date-and-time
| +--:(count)
| +-- count? uint32
+-- recurrence-description? string
+-- frequency? identityref
+-- interval? uint32
+-- period-timeticks* [period-start]
+-- period-start yang:timeticks
+-- period-end? yang:timeticks
Figure 6: 'recurrence-utc-with-periods' Grouping Tree Structure
The recurrence instances are specified by the union of occurrences
defined by both the recurrence rule and "period-timeticks" list.
This list uses the "yang:timeticks" type defined in [RFC6991].
Duplicate instances are ignored. The value of the "period-start"
instance MUST NOT exceed the value indicated by the value of the
"frequency" instance, i.e., the timeticks "timeticks" value must not exceed 100
in a secondly recurrence rule, and it must not exceed 6000 in a
minutely recurrence rule, and so on.
3.3.7. The "recurrence-time-zone-with-periods" Grouping
The "recurrence-time-zone-with-periods" grouping (Figure 7) uses the
"recurrence-with-time-zone" grouping (Section 3.3.5) and adds a
"period" list to define an aggregate set of repeating occurrences.
grouping recurrence-time-zone-with-periods:
+-- recurrence-first
| +-- start-time? yang:date-and-time
| +-- duration? duration
+-- time-zone-identifier? sys:timezone-name
+-- (recurrence-end)?
| +--:(until)
| | +-- until? yang:date-and-time
| +--:(count)
| +-- count? uint32
+-- recurrence-description? string
+-- frequency? identityref
+-- interval? uint32
+-- period* [period-start]
+-- period-description? string
+-- period-start yang:date-and-time
+-- time-zone-identifier? sys:timezone-name
+-- (period-type)?
+--:(explicit)
| +-- period-end? yang:date-and-time
+--:(duration)
+-- duration? duration
Figure 7: 'recurrence-time-zone-with-periods' Grouping Tree Structure
The recurrence instances are specified by the union of occurrences
defined by both the recurrence rule and "period" list. Duplicate
instances are ignored.
3.3.8. The "icalendar-recurrence" Grouping
The "icalendar-recurrence" grouping (Figure 8) uses the "recurrence-
time-zone-with-periods" grouping (Section 3.3.7) and defines more
data nodes to enrich the definition of recurrence. The structure of
the "icalendar-recurrence" grouping refers to the definition of the
recurrence component defined in Sections 3.3.10 and 3.8.5 of
[RFC5545].
grouping icalendar-recurrence:
+-- recurrence-first
| +-- start-time? yang:date-and-time
| +-- duration? duration
+-- time-zone-identifier? sys:timezone-name
+-- (recurrence-end)?
| +--:(until)
| | +-- until? yang:date-and-time
| +--:(count)
| +-- count? uint32
+-- recurrence-description? string
+-- frequency? identityref
+-- interval? uint32
+-- period* [period-start]
| +-- period-description? string
| +-- period-start yang:date-and-time
| +-- time-zone-identifier? sys:timezone-name
| +-- (period-type)?
| +--:(explicit)
| | +-- period-end? yang:date-and-time
| +--:(duration)
| +-- duration? duration
+-- bysecond* uint32
+-- byminute* uint32
+-- byhour* uint32
+-- byday* [weekday]
| +-- direction* int32
| +-- weekday schedule:weekday
+-- bymonthday* int32
+-- byyearday* int32
+-- byyearweek* int32
+-- byyearmonth* uint32
+-- bysetpos* int32
+-- workweek-start? schedule:weekday
+-- exception-dates* yang:date-and-time
Figure 8: 'icalendar-recurrence' Grouping Tree Structure
An array of the "bysecond" (or "byminute", "byminute" or "byhour") specifies a
list of seconds within a minute (or minutes within an hour, hour or hours
of the day). For example, within a "minutely" recurrence rule, the
values of "byminute" node "10" and "20" means mean the occurrences are
generated at the 10th and 20th minute within an hour, reducing the
number of recurrence instances from all minutes.
The parameter "byday" specifies a list of days of the week, with an
optional direction which that indicates the nth occurrence of a specific
day within the "monthly" or "yearly" frequency instance. Valid
values of "direction" are 1 to 5 or -5 to -1 within a "monthly"
recurrence rule; rule and 1 to 53 or -53 to -1 within a "yearly" recurrence
rule. 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). For example, within
a "yearly" recurrence rule, the values of "byyearmonth" instance instances "1"
and "2" means mean the occurrences are generated in January and February,
increasing the "yearly" recurrence from every year to every January
and February 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, and the "bysetpos" with a 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. Note that that, per Section 4.13 of
[I-D.ietf-netmod-rfc8407bis], [YANG-GUIDE], neither a
"default" nor a "mandatory" substatement is defined here because
there are cases (e.g., profiling) where using these statements is
problematic. YANG modules using this grouping SHOULD refine the
"workweek-start" node with either a "mandatory" or a "default" statement,
statement if it always needs to be configured or has a default value.
This MAY be ignored in cases such as when this grouping is used by
another grouping.
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 created by any of the specified
recurrence rule rules and date-times, date-times and then excluding any start date and
time values specified by "exception-dates" parameter.
3.3.9. The "schedule-status", "schedule-status-with-time-zone", and
"schedule-status-with-name" Groupings
The "schedule-status", "schedule-status-with-time-zone", and
"schedule-status-with-name" groupings (Figure 9) define common
parameters for scheduling management/status exposure. The "schedule-
status-with-time-zone" grouping has the same structure as "schedule-
status" but with an additional parameter to identify a time zone.
Similarly, the "schedule-status-with-name" grouping has the same
structure as "schedule-status" but with an additional parameter to
identify a schedule "schedule-name". These structures are defined in
the module to allow for better modularity and flexibility.
grouping schedule-status:
+-- state? identityref
+-- version? uint16
+-- schedule-type? identityref
+--ro local-time? yang:date-and-time
+--ro last-update? yang:date-and-time
+--ro counter? yang:counter32
+--ro last-occurrence? yang:date-and-time
+--ro upcoming-occurrence? yang:date-and-time
+--ro last-failed-occurrence? yang:date-and-time
+--ro failure-counter? yang:counter32
grouping schedule-status-with-time-zone:
+--ro time-zone-identifier? sys:timezone-name
+-- schedule-name? string
+-- state? identityref
+-- version? uint16
+-- schedule-type? identityref
+--ro local-time? yang:date-and-time
+--ro last-update? yang:date-and-time
+--ro counter? yang:counter32
+--ro last-occurrence? yang:date-and-time
+--ro upcoming-occurrence? yang:date-and-time
+--ro last-failed-occurrence? yang:date-and-time
+--ro failure-counter? yang:counter32
grouping schedule-status-with-name:
+-- schedule-name? string
+-- state? identityref
+-- version? uint16
+-- schedule-type? identityref
+--ro local-time? yang:date-and-time
+--ro last-update? yang:date-and-time
+--ro counter? yang:counter32
+--ro last-occurrence? yang:date-and-time
+--ro upcoming-occurrence? yang:date-and-time
+--ro last-failed-occurrence? yang:date-and-time
+--ro failure-counter? yang:counter32
Figure 9: 'schedule-status-*' Groupings Tree Structure
The "schedule-name" parameter is useful to uniquely identify a
schedule in a network device or controller if multiple scheduling
contexts exist.
The "state" parameter is defined to configure/expose the scheduling
state, depending on the use of the grouping. For a recurrence-based
schedule, it represents the state of the overall recurrence. The
"identityref" type is used for this parameter to allow extensibility
in future modules.
The "version" parameter is used to track the current schedule version
information. The version can be incremented by the entity that
created the schedule. The "last-update" parameter identifies when
the schedule was last modified. In some contexts, this parameter can
be used to track the configuration of a given schedule. In such
cases, the "version" may not be used.
The "schedule-type" parameter identifies the type of the current
schedule. The "counter", "last-occurrence", and "upcoming-
occurrence" data nodes are only available when the "schedule-type" is
"recurrence".
When no time zone is included, "local-time" reports the actual local
time as seen by the entity that hosts a schedule. This parameter can
be used by a controller to infer the offset to UTC. This use is
similar to the use of "schedLocalTime" in [RFC3231].
"last-failed-occurrence" and "failure-counter" report the last
failure that occurred and the count of failures for this schedule.
Unless new parameters/operations are defined to allow the count of
failures to be reset, "failure-counter" is reset by default only when
the schedule starts.
The current groupings capture common parameters that are applicable
to typical scheduling contexts known so far. Future modules can
define other useful parameters as needed. For example, in a
scheduling context with multiple system sources to feed the
schedules, the "source" and "precedence" parameters may be needed to
reflect how schedules from different sources should be prioritized.
3.4. Features Use and Augmentations
Appendix B.1 provides an example about how the features defined in
Section 3.1 can be used. Implementations may support a basic
recurrence rule or an advanced one one, as needed, by declaring different
features. Whether only one or both features are supported is
implementation specific and depends on the specific scheduling
context.
The common schedule groupings (Section 3.3) can also be augmented to
support specific needs. As an example, Appendix B.2 demonstrates how
additional parameters can be added to comply with specific schedule
needs.
4. Some Usage Restrictions
There are some restrictions that need to be followed when using
groupings defined in the "ietf-schedule" YANG module (Section 3.3):
* The instant in time represented by "period-start" MUST be before
the "period-end" for the "period-of-time" grouping
(Section 3.3.2).
* The combination of the day, month, and year represented for date
and time values MUST be valid. See Section 5.7 of [RFC3339] for
the maximum day number based on the month and year.
* Unless deployed in contexts where time synchronization is not
subject to leap second adjustments (e.g., Section 4.3 of
[I-D.ietf-ntp-ntpv5]), [NTPv5]),
the second for date and time values SHOULD have the value "60" at
the end of months in which a leap second occurs.
* Schedules received with a starting time in the past with respect
to current time SHOULD be ignored. When a local policy is
provided, an implementation MAY omit the past occurrences and
start immediately (e.g., for a period-based schedule) or starts start
from the date and time when the recurrence pattern is first
satisfied from the current time (e.g., for a recurrence-based
schedule).
5. Relationship to the DISMAN-SCHEDULE-MIB
[RFC3231] specifies a Management Information Base (MIB) used to
schedule management operations periodically or at specified dates and
times.
Although no data nodes are defined in this document, Table 1 lists
how the main objects in the DISMAN-SCHEDULE-MIB can be mapped to YANG
parameters.
+==================+=========================+
| MIB Object | YANG |
+==================+=========================+
| schedLocalTime | local-time |
+------------------+-------------------------+
| schedType | schedule-type |
+------------------+-------------------------+
| schedName | schedule-name |
+------------------+-------------------------+
| schedOwner | Not Supported |
+------------------+-------------------------+
| schedDescr | description |
+------------------+-------------------------+
| schedInterval | interval |
+------------------+-------------------------+
| schedWeekDay | weekday |
+------------------+-------------------------+
| schedMonth | byyearmonth |
+------------------+-------------------------+
| schedDay | bymonthday |
+------------------+-------------------------+
| schedHour | byhour |
+------------------+-------------------------+
| schedMinute | byminute |
+------------------+-------------------------+
| schedContextName | Not Supported |
+------------------+-------------------------+
| schedAdminStatus | state |
+------------------+-------------------------+
| schedOperStatus | state |
+------------------+-------------------------+
| schedFailures | failure-counter |
+------------------+-------------------------+
| schedLastFailure | Not Supported |
+------------------+-------------------------+
| schedLastFailed | last-failed-occurrence |
+------------------+-------------------------+
| schedStorageType | Not Supported |
+------------------+-------------------------+
| schedVariable | Not applicable |
+------------------+-------------------------+
| schedValue | Not applicable |
+------------------+-------------------------+
| schedTriggers | counter/failure-counter |
+------------------+-------------------------+
Table 1: YANG/MIB Mapping
6. The "ietf-schedule" YANG Module
This module imports types defined in [RFC6991] [RFC5545], [RFC6991], and
[RFC7317].
<CODE BEGINS>
file "ietf-schedule@2025-05-30.yang" "ietf-schedule@2026-02-18.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;
reference
"RFC 6991: Common YANG Data Types";
}
import ietf-system {
prefix sys;
reference
"RFC 7317: A YANG Data Model for System Management";
}
organization
"IETF NETMOD Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/netmod/>
WG List: <mailto:netmod@ietf.org>
Editor: Qiufang Ma
<mailto:maqiufang1@huawei.com
<mailto:maqiufang1@huawei.com>
Author: Qin Wu
<mailto:bill.wu@huawei.com>
Editor: Mohamed Boucadair
<mailto:mohamed.boucadair@orange.com>
Author: Daniel King
<mailto:d.king@lancaster.ac.uk>";
description
"This YANG module defines a set of common types and groupings
which
that are applicable for scheduling purposes purposes, such as events,
policy,
policies, services, or resources based on date and time.
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.
Copyright (c) 2025 2026 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).
All revisions of IETF and IANA published modules can be found
at the YANG Parameters registry group
(https://www.iana.org/assignments/yang-parameters).
This version of this YANG module is part of RFC XXXX; 9922; 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',
All revisions of IETF and 'OPTIONAL' in this document are to IANA-maintained modules can be interpreted as
described in BCP 14 (RFC 2119) (RFC 8174) when, and only when,
they appear found
in all capitals, as shown here."; the 'YANG Parameters' registry group
(https://www.iana.org/assignments/yang-parameters).";
revision 2025-05-30 2026-02-18 {
description
"Initial revision.";
reference
"RFC XXXX: 9922: A Common YANG Data Model for Scheduling";
}
feature basic-recurrence {
description
"Indicates that the server supports configuring a basic
scheduled recurrence.";
}
feature icalendar-recurrence {
description
"Indicates that the server supports configuring a comprehensive
scheduled iCalendar recurrence"; recurrence.";
reference
"RFC 5545: Internet Calendaring and Scheduling Core Object
Specification (iCalendar),
Sections 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 schedule-type {
description
"Base identity for schedule type.";
}
identity one-shot {
base schedule-type;
description
"Indicates a one-shot schedule. That is a schedule that
will trigger an action with the duration being specified as
0 or end time being specified as the same as the start time,
and then the schedule will disable itself.";
}
identity period {
base schedule-type;
description
"Indicates a period-based schedule consisting of either a
start and end or a start and positive duration of time. If
neither an end nor a duration is indicated, the period is
considered to last forever.";
}
identity recurrence {
base schedule-type;
description
"Indicates a recurrence-based schedule.";
}
identity frequency-type {
description
"Base identity for frequency type.";
}
identity secondly {
base frequency-type;
description
"Indicates a repeating rule based on an interval of
a second or more.";
}
identity minutely {
base frequency-type;
description
"Indicates a repeating rule based on an interval of
a minute or more.";
}
identity hourly {
base frequency-type;
description
"Indicates a repeating rule based on an interval of
an hour or more.";
}
identity daily {
base frequency-type;
description
"Indicates a repeating rule based on an interval of
a day or more.";
}
identity weekly {
base frequency-type;
description
"Indicates a repeating rule based on an interval of
a week or more.";
}
identity monthly {
base frequency-type;
description
"Indicates a repeating rule based on an interval of
a month or more.";
}
identity yearly {
base frequency-type;
description
"Indicates a repeating rule based on an interval of
a year or more.";
}
identity schedule-state {
description
"Base identity for schedule state.";
}
identity enabled {
base schedule-state;
description
"Indicates a schedule with an enabled state.";
}
identity finished {
base schedule-state;
description
"Indicates a schedule with a finished state.
The finished state indicates that the schedule has ended.";
}
identity disabled {
base schedule-state;
description
"Indicates a schedule with a disabled state.";
}
identity out-of-date {
base schedule-state;
description
"Indicates a schedule that is received out-of-date.";
}
identity conflicted {
base schedule-state;
description
"Indicates a schedule with a conflicted state with other
schedules.";
}
identity discard-action-type {
description
"Base identity for the action for the responder to take
when a requested schedule cannot be accepted for any
reason and is discarded.";
}
identity warning {
base discard-action-type;
description
"Indicates that a warning message is generated
when a schedule is discarded.";
}
identity error {
base discard-action-type;
description
"Indicates that an error message is generated
when a schedule is discarded.";
}
identity silently-discard {
base discard-action-type;
description
"Indicates that a schedule that is not valid is silently
discarded.";
}
grouping generic-schedule-params {
description
"Includes a set of generic parameters that are followed by
the entity that supports schedules.
Such parameters are used as guards to prevent, e.g., stale
configuration.";
leaf description {
type string;
description
"Provides a description of the schedule.";
}
leaf time-zone-identifier {
type sys:timezone-name;
description
"Indicates the identifier for the time zone. This parameter
MUST be specified if any of the date and time values are
in the format of local time. It MUST NOT be applied to
date and time values which that are specified in the format of
UTC or time zone offset to UTC.";
}
leaf validity {
type yang:date-and-time;
description
"Specifies the date and time after which a schedule will not
be considered as valid. This parameter takes precedence
over similar attributes that are provided at the schedule
instance itself.";
}
leaf max-allowed-start {
type yang:date-and-time;
description
"Specifies the maximum scheduled start date and time.
A requested schedule whose first instance occurs after
this value cannot be accepted by the entity. Specifically,
a requested schedule will be rejected if the first
occurrence of that schedule exceeds 'max-allowed-start'.";
}
leaf min-allowed-start {
type yang:date-and-time;
description
"Specifies the minimum scheduled start date and time.
A requested schedule whose first instance occurs before
this value cannot be accepted by the entity. Specifically,
a requested schedule will be rejected if the first
occurrence of that schedule is scheduled before
'min-allowed-start'.";
}
leaf max-allowed-end {
type yang:date-and-time;
description
"A requested schedule will be rejected if the end time of
the last occurrence exceeds 'max-allowed-end'.";
}
leaf discard-action {
type identityref {
base discard-action-type;
}
description
"Specifies the behavior when a schedule is discarded for
any reason, e.g., failing to satisfy the guards in this
grouping or it is being received out-of-date.";
}
}
grouping period-of-time {
description
"This grouping is defined for the period of time property.";
reference
"RFC 5545: Internet Calendaring and Scheduling Core Object
Specification (iCalendar), Section 3.3.9";
leaf period-description {
type string;
description
"Provides a description of the period.";
}
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. This parameter
MUST be specified if either the 'period-start' or
'period-end' value is reported in local time format.
It MUST NOT be applied to date and time values which that are
specified in the format of UTC or time zone offset
to UTC.";
}
choice period-type {
description
"Indicates the type of the time period. Two types are
supported. If no choice is indicated, the period is
considered to last forever.";
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
"A period of time is defined by a start and end time.
The start MUST be no later than the end. The period
is considered as a one-shot schedule if the end time
is the same as the start time.";
}
}
case duration {
description
"A period of time is defined by a start and a non-negative
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 non-negative duration of time. This value is
equivalent to the format of duration 'duration' type except that
the value cannot be negative. The period is considered
to be a one-shot schedule if the value is 0.";
}
}
}
}
grouping recurrence-basic {
description
"A simple definition of recurrence.";
leaf recurrence-description {
type string;
description
"Provides a description of the recurrence.";
}
leaf frequency {
type identityref {
base frequency-type;
}
description
"Specifies the frequency type of the recurrence rule.";
}
leaf interval {
type uint32 {
range "1..max";
}
must '../frequency' {
error-message "Frequency must be provided.";
}
description
"A positive integer representing the interval at which the
recurrence rule repeats. For example, within a 'daily'
recurrence rule, a value of '8' means every eight days.";
}
}
grouping recurrence-utc {
description
"A simple definition of recurrence with time specified in
UTC format.";
container recurrence-first {
description
"Specifies the first instance of the recurrence. If
unspecified, the recurrence is considered to start from
the date and time when the recurrence pattern is first
satisfied.";
leaf start-time-utc {
type yang:date-and-time;
description
"Defines the date and time of the first instance
in the recurrence set. A UTC format MUST be used.";
}
leaf duration {
type uint32;
units "seconds";
description
"When specified, it indicates how long the first occurrence
lasts. Unless specified otherwise, it also applies to all
the other instances in the recurrence set.";
}
}
choice recurrence-end {
description
"Modes to control the end of a recurrence rule. If no
choice is indicated, the recurrence rule is considered
to repeat forever.";
case until {
description
"This case defines a way that limits the end of
a recurrence rule in an inclusive manner.";
leaf utc-until {
type yang:date-and-time;
description
"This parameter specifies a date and time value to
inclusively terminate the recurrence in UTC format.
That is, if the value specified by this parameter is
synchronized with the specified recurrence rule, it
becomes the last instance of the recurrence rule.";
}
}
case count {
description
"This case defines the number of occurrences at which
to terminate the recurrence rule.";
leaf count {
type uint32 {
range "1..max";
}
description
"The positive number of occurrences at which to
terminate the recurrence rule.";
}
}
}
uses recurrence-basic;
}
grouping recurrence-with-time-zone {
description
"A simple definition of recurrence to specify a recurrence
rule with a time zone.";
container recurrence-first {
description
"Specifies the first instance of the recurrence. If
unspecified, the recurrence is considered to start from
the date and time when the recurrence pattern is first
satisfied.";
leaf start-time {
type yang:date-and-time;
description
"Defines the date and time of the first instance
in the recurrence set.";
}
leaf duration {
type duration;
description
"When specified, it indicates how long the first
occurrence last. lasts. Unless specified otherwise, it also
applies to all the other instances in the recurrence
set.";
}
}
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 either
the 'start-time' or 'until' value is reported in local
time format. It MUST NOT be applied to date and time
values which that are specified in the format of UTC or time
zone offset to UTC.";
}
choice recurrence-end {
description
"Modes to terminate the recurrence rule. If no choice is
indicated, the recurrence rule is considered to repeat
forever.";
case until {
description
"The end of the recurrence rule is indicated by a specific
date-and-time value in an inclusive manner.";
leaf until {
type yang:date-and-time;
description
"Specifies a date and time value to inclusively terminate
the recurrence. Thats That is, if the value specified by
this parameter is synchronized with the specified
recurrence, it becomes the last instance of the
recurrence.";
}
}
case count {
description
"The end of the recurrence is indicated by the number
of occurrences.";
leaf count {
type uint32 {
range "1..max";
}
description
"The positive number of occurrences at which to
terminate the recurrence.";
}
}
}
uses recurrence-basic;
}
grouping recurrence-utc-with-periods {
description
"This grouping defines an aggregate set of repeating
occurrences with UTC time format. The recurrence instances
are specified by the occurrences defined by both the
recurrence rule and 'period-timeticks' list. Duplicate
instances are ignored.";
uses recurrence-utc;
list period-timeticks {
key "period-start";
description
"A list of periods 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 'period-start' must not exceed the frequency
interval.";
}
description
"Start time of the schedule within one recurrence.
Given that the value is in timeticks format
(i.e., 1/100 of a second), the values in the must
statement translate to: to 100 = 1s 1 s (secondly),
6000 = 60 s = 1 min (minutely), and so on for all
instances in the must statement invariant.";
}
leaf period-end {
type yang:timeticks;
description
"End time of the schedule within one recurrence.
The period start MUST be no later than the period
end.";
}
}
}
grouping recurrence-time-zone-with-periods {
description
"This grouping defines an aggregate set of repeating
occurrences with local time format and time zone specified.
The recurrence instances are specified by the occurrences
defined by both the recurrence rule and 'period' list.
Duplicate instances are ignored.";
uses recurrence-with-time-zone;
list period {
key "period-start";
description
"A list of periods with date-and-time formats.";
uses period-of-time;
}
}
grouping icalendar-recurrence {
description
"This grouping specifies properties of a recurrence rule.";
reference
"RFC 5545: Internet Calendaring and Scheduling Core Object
Specification (iCalendar), Section 3.8.5";
uses recurrence-time-zone-with-periods;
leaf-list bysecond {
type uint32 {
range "0..60";
}
description
"Specifies a list of seconds within a minute.";
}
leaf-list byminute {
type uint32 {
range "0..59";
}
description
"Specifies 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 Monday within the month, whereas
-1 monday represents the last monday Monday of the month.";
}
leaf weekday {
type schedule:weekday;
description
"Corresponds 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 'byxxx' (bysecond, byminute, etc.) rule
part .";
part.";
}
leaf workweek-start {
type schedule:weekday;
description
"Specifies the day on which the workweek starts.";
}
leaf-list exception-dates {
type yang:date-and-time;
description
"Defines a list of exceptions for recurrence.";
}
}
grouping schedule-status {
description
"This grouping defines common properties of scheduling
status.";
leaf state {
type identityref {
base schedule-state;
}
description
"Indicates the current state of the schedule.";
}
leaf version {
type uint16;
description
"Indicates the version number of the schedule.";
}
leaf schedule-type {
type identityref {
base schedule-type;
}
description
"Indicates the schedule type.";
}
leaf local-time {
type yang:date-and-time;
config false;
description
"Reports the local time as used by the entity that
hosts the schedule.";
}
leaf last-update {
type yang:date-and-time;
config false;
description
"Reports the timestamp that of when the schedule is last
updated.";
}
leaf counter {
when "derived-from-or-self(../schedule-type, "
+ "'schedule:recurrence')";
type yang:counter32;
config false;
description
"The number of occurrences while invoking the scheduled
action successfully. The count wraps around when it reaches
the maximum value.";
}
leaf last-occurrence {
when "derived-from-or-self(../schedule-type, "
+ "'schedule:recurrence')";
type yang:date-and-time;
config false;
description
"Indicates the timestamp of last occurrence.";
}
leaf upcoming-occurrence {
when "derived-from-or-self(../schedule-type, "
+ "'schedule:recurrence')"
+ "and derived-from-or-self(../state, 'schedule:enabled')";
type yang:date-and-time;
config false;
description
"Indicates the timestamp of next occurrence.";
}
leaf last-failed-occurrence {
when "derived-from-or-self(../schedule-type, "
+ "'schedule:recurrence')";
type yang:date-and-time;
config false;
description
"Indicates the timestamp of last failed action triggered by
the schedule.";
}
leaf failure-counter {
when "derived-from-or-self(../schedule-type, "
+ "'schedule:recurrence')";
type yang:counter32;
config false;
description
"Counts the number of failures while invoking the scheduled
action.";
}
}
grouping schedule-status-with-time-zone {
description
"This grouping defines common properties of scheduling
status, including timezone"; timezone.";
leaf time-zone-identifier {
type sys:timezone-name;
config false;
description
"Indicates the identifier for the time zone in a time
zone database.";
}
uses schedule-status;
}
grouping schedule-status-with-name {
description
"This grouping defines common properties of scheduling
status, including a schedule name.";
leaf schedule-name {
type string;
description
"The schedule identifier that uniquely identifies a
schedule within a device, controller, network, etc.
The unicity scope depends on the implementation.";
}
uses schedule-status;
}
}
<CODE ENDS>
7. Security Considerations
This section uses is modeled after the template described in Section 3.7
of
[I-D.ietf-netmod-rfc8407bis]. [YANG-GUIDE].
The "ietf-schedule" YANG module specified in this document defines
schema for a data model that is designed
to be accessed via YANG-based management protocols, such as NETCONF
[RFC6241] or and RESTCONF [RFC8040]. These YANG-based management
protocols (1) have to use a secure transport layer (e.g., SSH
[RFC4252], TLS [RFC8446], and QUIC [RFC9000]) and (2) have to use
mutual authentication.
The Network Configuration Access Control Model (NACM) [RFC8341]
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 identities, 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" "ietf-
schedule" module that need to be considered.
Modules that use the groupings that are defined in this document
should identify the corresponding security considerations, e.g.,: for
example:
* Scheduling depends on reliable and accurate time synchronization.
Inaccurate date and time setting can lead to scheduling events
being triggered at incorrect intervals, potentially causing system
failures or security vulnerabilities.
* Recurring events may conceal abnormal behavior or security
threats, which may be drowned out by normal events, especially
when they are triggered frequently.
* The absence of detailed logs and audit records of each occurrence
trigger time and action results, results and so on, therefore may make security
incidents difficult to trace.
* Care must be taken when defining recurrences occurring very often
and frequent that can be an additional source of attacks by
keeping the system permanently busy with the management of
scheduling.
8. IANA Considerations
8.1. The "IETF XML" IETF XML Registry
This document registers has registered the following URI in the "IETF XML
Registry" [RFC3688].
URI: urn:ietf:params:xml:ns:yang:ietf-schedule
Registrant Contact: The IESG.
XML: N/A, N/A; the requested URI is an XML namespace.
8.2. The "YANG YANG Module Names" Names Registry
This document registers has registered the following YANG module in the "YANG
Module Names" registry [RFC6020].
name:
Name: ietf-schedule
namespace: urn:ietf:params:xml:ns:yang:ietf-schedule
prefix: schedule
maintained
Maintained by IANA? IANA: N
reference:
Namespace: urn:ietf:params:xml:ns:yang:ietf-schedule
Prefix: schedule
Reference: RFC XXXX 9922
9. References
9.1. 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,
<https://www.rfc-editor.org/rfc/rfc2119>.
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3231] Levi, D. and J. Schoenwaelder, "Definitions of Managed
Objects for Scheduling Management Operations", RFC 3231,
DOI 10.17487/RFC3231, January 2002,
<https://www.rfc-editor.org/rfc/rfc3231>.
<https://www.rfc-editor.org/info/rfc3231>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/rfc/rfc3688>.
<https://www.rfc-editor.org/info/rfc3688>.
[RFC5545] Desruisseaux, B., Ed., "Internet Calendaring and
Scheduling Core Object Specification (iCalendar)",
RFC 5545, DOI 10.17487/RFC5545, September 2009,
<https://www.rfc-editor.org/rfc/rfc5545>.
<https://www.rfc-editor.org/info/rfc5545>.
[RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for
the Network Configuration Protocol (NETCONF)", RFC 6020,
DOI 10.17487/RFC6020, October 2010,
<https://www.rfc-editor.org/rfc/rfc6020>.
<https://www.rfc-editor.org/info/rfc6020>.
[RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types",
RFC 6991, DOI 10.17487/RFC6991, July 2013,
<https://www.rfc-editor.org/rfc/rfc6991>.
<https://www.rfc-editor.org/info/rfc6991>.
[RFC7317] Bierman, A. and M. Bjorklund, "A YANG Data Model for
System Management", RFC 7317, DOI 10.17487/RFC7317, August
2014, <https://www.rfc-editor.org/rfc/rfc7317>. <https://www.rfc-editor.org/info/rfc7317>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/rfc/rfc7950>.
<https://www.rfc-editor.org/info/rfc7950>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/rfc/rfc8174>. <https://www.rfc-editor.org/info/rfc8174>.
[RFC8341] Bierman, A. and M. Bjorklund, "Network Configuration
Access Control Model", STD 91, RFC 8341,
DOI 10.17487/RFC8341, March 2018,
<https://www.rfc-editor.org/rfc/rfc8341>.
<https://www.rfc-editor.org/info/rfc8341>.
[W3C.XML1.0]
Bray, T., Ed., Paoli, J., Ed., Sperberg-McQueen, C. M.,
Ed., Maler, E., Ed., and F. Yergeau, Ed., "Extensible
Markup Language (XML) 1.0 (Fifth Edition)", W3C
Recommendation, 26 November 2008,
<https://www.w3.org/TR/2008/REC-xml-20081126/>.
9.2. Informative References
[I-D.ietf-netmod-eca-policy]
[NETMOD-ECA-POLICY]
Wu, Q., Bryskin, I., Birkholz, H., Liu, X., and B. Claise,
"A YANG Data model for ECA Policy Management", Work in
Progress, Internet-Draft, draft-ietf-netmod-eca-policy-01,
19 February 2021, <https://datatracker.ietf.org/doc/html/
draft-ietf-netmod-eca-policy-01>.
[I-D.ietf-netmod-rfc8407bis]
Bierman, A., Boucadair, M., and Q. Wu, "Guidelines for
Authors and Reviewers of Documents Containing YANG Data
Models", Work in Progress, Internet-Draft, draft-ietf-
netmod-rfc8407bis-28, 5 June 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
rfc8407bis-28>.
[I-D.ietf-ntp-ntpv5]
[NTPv5] Lichvar, M. and T. Mizrahi, "Network Time Protocol Version
5", Work in Progress, Internet-Draft, draft-ietf-ntp-
ntpv5-05, 2 July
ntpv5-07, 16 October 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-ntp-
ntpv5-05>.
[I-D.ietf-opsawg-scheduling-oam-tests]
Contreras, L. M. and V. Lopez, "A YANG Data Model for
Network Diagnosis using Scheduled Sequences of OAM Tests",
Work in Progress, Internet-Draft, draft-ietf-opsawg-
scheduling-oam-tests-01, 7 July 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-opsawg-
scheduling-oam-tests-01>.
[I-D.ietf-opsawg-ucl-acl]
Ma, Q., Wu, Q., Boucadair, M., and D. King, "A YANG Data
Model and RADIUS Extension for Policy-based Network Access
Control", Work in Progress, Internet-Draft, draft-ietf-
opsawg-ucl-acl-07, 20 March 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-opsawg-
ucl-acl-07>.
[I-D.ietf-tvr-schedule-yang]
Qu, Y., Lindem, A., Kinzie, E., Fedyk, D., and M.
Blanchet, "YANG Data Model for Scheduled Attributes", Work
in Progress, Internet-Draft, draft-ietf-tvr-schedule-yang-
05, 4 July 2025, <https://datatracker.ietf.org/doc/html/
draft-ietf-tvr-schedule-yang-05>.
[I-D.liu-netmod-yang-schedule]
Liu, X., Bryskin, I., Beeram, V. P., Saad, T., Shah, H.,
and O. G. de Dios, "A YANG Data Model for Configuration
Scheduling", Work in Progress, Internet-Draft, draft-liu-
netmod-yang-schedule-05, 1 March 2018,
<https://datatracker.ietf.org/doc/html/draft-liu-netmod-
yang-schedule-05>.
ntpv5-07>.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/rfc/rfc3339>.
<https://www.rfc-editor.org/info/rfc3339>.
[RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH)
Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252,
January 2006, <https://www.rfc-editor.org/rfc/rfc4252>. <https://www.rfc-editor.org/info/rfc4252>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/rfc/rfc6241>.
<https://www.rfc-editor.org/info/rfc6241>.
[RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG",
RFC 7951, DOI 10.17487/RFC7951, August 2016,
<https://www.rfc-editor.org/rfc/rfc7951>.
<https://www.rfc-editor.org/info/rfc7951>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/rfc/rfc8040>.
<https://www.rfc-editor.org/info/rfc8040>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/rfc/rfc8340>.
<https://www.rfc-editor.org/info/rfc8340>.
[RFC8413] Zhuang, Y., Wu, Q., Chen, H., and A. Farrel, "Framework
for Scheduled Use of Resources", RFC 8413,
DOI 10.17487/RFC8413, July 2018,
<https://www.rfc-editor.org/rfc/rfc8413>.
<https://www.rfc-editor.org/info/rfc8413>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/rfc/rfc8446>.
<https://www.rfc-editor.org/info/rfc8446>.
[RFC9000] Iyengar, J., Ed. and M. Thomson, Ed., "QUIC: A UDP-Based
Multiplexed and Secure Transport", RFC 9000,
DOI 10.17487/RFC9000, May 2021,
<https://www.rfc-editor.org/rfc/rfc9000>.
<https://www.rfc-editor.org/info/rfc9000>.
[RFC9657] Birrane, III, E., Kuhn, N., Qu, Y., Taylor, R., and L.
Zhang, "Time-Variant Routing (TVR) Use Cases", RFC 9657,
DOI 10.17487/RFC9657, October 2024,
<https://www.rfc-editor.org/rfc/rfc9657>.
<https://www.rfc-editor.org/info/rfc9657>.
[YANG-CONFIG-SCHEDULE]
Liu, X., Bryskin, I., Beeram, V. P., Saad, T., Shah, H.
C., and O. G. de Dios, "A YANG Data Model for
Configuration Scheduling", Work in Progress, Internet-
Draft, draft-liu-netmod-yang-schedule-05, 1 March 2018,
<https://datatracker.ietf.org/doc/html/draft-liu-netmod-
yang-schedule-05>.
[YANG-GUIDE]
Bierman, A., Boucadair, M., and Q. Wu, "Guidelines for
Authors and Reviewers of Documents Containing YANG Data
Models", Work in Progress, Internet-Draft, draft-ietf-
netmod-rfc8407bis-28, 5 June 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-netmod-
rfc8407bis-28>.
[YANG-NAC] Ma, Q., Wu, Q., Boucadair, M., and D. King, "A YANG Data
Model and RADIUS Extension for Policy-Based Network Access
Control", Work in Progress, Internet-Draft, draft-ietf-
opsawg-ucl-acl-12, 3 February 2026,
<https://datatracker.ietf.org/doc/html/draft-ietf-opsawg-
ucl-acl-12>.
[YANG-OAM] Contreras, L. M., Lopez, V., and Q. Wu, "A YANG Data Model
for Network Diagnosis using Scheduled Sequences of OAM
Tests", Work in Progress, Internet-Draft, draft-ietf-
opsawg-scheduling-oam-tests-03, 20 October 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-opsawg-
scheduling-oam-tests-03>.
[YANG-SCHEDULE]
Qu, Y., Lindem, A., Kinzie, E., Fedyk, D., and M.
Blanchet, "YANG Data Model for Scheduled Attributes", Work
in Progress, Internet-Draft, draft-ietf-tvr-schedule-yang-
08, 9 February 2026,
<https://datatracker.ietf.org/doc/html/draft-ietf-tvr-
schedule-yang-08>.
Appendix A. Examples of Scheduling Format Representation
This section provides some examples to illustrate the use of the
period and recurrence formats defined in Section 6. The following
modules are used for illustration purposes and make examples
verifiable:
module example-sch-usage-1 {
yang-version 1.1;
namespace "http://example.com/example-sch-usage-1";
prefix "ex-schu-1";
import ietf-schedule {
prefix "schedule";
}
container generic-schedule-params {
uses schedule:generic-schedule-params;
}
container schedule-status {
uses schedule:schedule-status;
}
}
module example-sch-usage-2 {
yang-version 1.1;
namespace "http://example.com/example-sch-usage-2";
prefix "ex-schu2";
import ietf-schedule {
prefix "schedule";
}
container period-of-time {
uses schedule:period-of-time;
}
}
module example-sch-usage-3 {
yang-version 1.1;
namespace "http://example.com/example-sch-usage-3";
prefix "ex-schu-3";
import ietf-schedule {
prefix "schedule";
}
container recurrence-basic {
uses schedule:recurrence-basic {
refine frequency {
mandatory true;
}
refine interval {
default 1;
}
}
}
}
module example-sch-usage-4 {
yang-version 1.1;
namespace "http://example.com/example-sch-usage-4";
prefix "ex-schu-4";
import ietf-schedule {
prefix "schedule";
}
container recurrence-utc {
uses schedule:recurrence-utc;
}
}
module example-sch-usage-5 {
yang-version 1.1;
namespace "http://example.com/example-sch-usage-5";
prefix "ex-schu-5";
import ietf-schedule {
prefix "schedule";
}
container recurrence-with-time-zone {
uses schedule:recurrence-with-time-zone;
}
}
module example-sch-usage-6 {
yang-version 1.1;
namespace "http://example.com/example-sch-usage-6";
prefix "ex-schu-6";
import ietf-schedule {
prefix "schedule";
}
container recurrence-utc-with-date-times {
uses schedule:recurrence-utc-with-periods;
}
}
module example-sch-usage-7 {
yang-version 1.1;
namespace "http://example.com/example-sch-usage-7";
prefix "ex-schu-8";
import ietf-schedule {
prefix "schedule";
container recurrence-time-zone-with-date-times {
uses schedule:recurrence-time-zone-with-periods;
}
}
module example-sch-usage-8 {
yang-version 1.1;
namespace "http://example.com/example-sch-usage-8";
prefix "ex-schu-8";
container icalendar-recurrence {
uses schedule:icalendar-recurrence {
refine workweek-start {
default monday;
}
}
}
}
For each example, only the message body is provided with JSON JSON, which
is used for encoding per the guidance in [RFC7951].
A.1. The "generic-schedule-params" Grouping
Figure 10 illustrates the example of a requested schedule that needs
to start no earlier than 08:00 AM, January 1, 2025 and end no later
than 8:00 PM, January 31, 2025 (Beijing time). Schedule requests
that fail to meet the requirements are ignored by the system system, as
indicated by "discard-action".
{
"example-sch-usage-1:generic-schedule-params": {
"time-zone-identifier": "China/Beijing",
"min-allowed-start": "2025-01-01T08:00:00",
"max-allowed-end": "2025-01-31T20:00:00",
"discard-action": "ietf-schedule:silently-discard"
}
}
Figure 10: Generic Parameters with 'max-allowed-end' for Schedule
Validation
To illustrate the difference between "max-allowed-end" and "validity"
parameters, Figure 11 shows the example of a requested schedule that
needs to start no earlier than 08:00 AM, January 1, 2025 (Beijing
time). Schedule requests that fail to meet the requirements are
ignored by the system system, as indicated by "discard-action". The
requested schedule may end after 8:00 PM, January 31, 2025, but any
occurrences that are generated after that time would not be
considered as valid.
{
"example-sch-usage-1:generic-schedule-params": {
"time-zone-identifier": "China/Beijing",
"validity": "2025-01-31T20:00:00",
"min-allowed-start": "2025-01-01T08:00:00",
"discard-action": "ietf-schedule:silently-discard"
}
}
Figure 11: Generic Parameters with 'validity' for Schedule Validation
A.2. The "period-of-time" Grouping
Figure 12 shows an example of a period that starts at 08:00:00 UTC, UTC on
January 1, 2025 and ends at 18:00:00 UTC on December 31, 2027.
{
"example-sch-usage-2:period-of-time": {
"period-start": "2025-01-01T08:00:00Z",
"period-end": "2027-12-31T18:00:00Z"
}
}
Figure 12: Simple Start/End Schedule
An example of a period that starts at 08:00:00 UTC, UTC on January 1, 2025
and lasts 15 days and 5 hours and 20 minutes is encoded as shown in
Figure 13.
{
"example-sch-usage-2:period-of-time": {
"period-start": "2025-01-01T08:00:00Z",
"duration": "P15DT05:20:00"
}
}
Figure 13: Simple Schedule with Duration
An example of a period that starts at 2:00 A.M. AM in Los Angeles on
November 19, 2025 and lasts 20 weeks is depicted in Figure 14.
{
"example-sch-usage-2:period-of-time": {
"period-start": "2025-11-19T02:00:00",
"time-zone-identifier": "America/Los_Angeles",
"duration": "P20W"
}
}
Figure 14: Simple Schedule with Time Zone Indication
A.3. The "recurrence-basic" Grouping
Figure 17 15 indicates a recurrence of every 2 days days, which starts
immediately and repeats forever:
{
"example-sch-usage-3:recurrence-basic": {
"recurrence-description": "forever recurrence rule",
"frequency": "ietf-schedule:daily",
"interval": 2
}
}
Figure 15: Simple Schedule with Recurrence
A.4. The "recurrence-utc" Grouping
Figure 16 indicates a recurrence from 8:00 AM to 9:00 AM every day,
from December 1 to December 31, 2025 in UTC:
{
"example-sch-usage-4:recurrence-utc": {
"recurrence-first": {
"start-time-utc": "2025-12-01T08:00:00Z",
"duration": 3600
},
"frequency": "ietf-schedule:daily",
"interval": 1,
"utc-until": "2025-12-31T23:59:59Z"
}
}
Figure 16: Simple Schedule with Recurrence in UTC
A.5. The "recurrence-with-time-zone" Grouping
Figure 17 indicates a recurrence of every 2 hours for 10 occurrences,
lasting occurrences
that lasts 10 minutes, minutes and starting starts at 3 p.m. PM on December 1, 2025 in New
York:
{
"example-sch-usage-5:recurrence-with-time-zone": {
"recurrence-first": {
"start-time": "2025-12-01T15:00:00",
"duration": "PT00:10:00",
"time-zone-identifier": "America/New_York"
},
"frequency": "ietf-schedule:hourly",
"interval": 2,
"count": 10
}
}
Figure 17: Simple Schedule with Recurrence with Time Zone Indication
A.6. The "recurrence-utc-with-periods" Grouping
Figure 18 indicates a recurrence that occurs every two days starting
at 9:00 AM and 3:00 PM for a duration of 30 minutes and 40 minutes minutes,
respectively, from 2025-06-01 to 2025-06-30 in UTC:
{
"example-sch-usage-6:recurrence-utc-with-periods": {
"recurrence-first": {
"start-time-utc": "2025-06-01T09:00:00Z"
},
"frequency": "ietf-schedule:daily",
"interval": 2,
"utc-until": "2025-06-30T23:59:59Z",
"period-timeticks": [
{
"period-start": "3240000",
"period-end": "3420000"
},
{
"period-start": "5400000",
"period-end": "5640000"
}
]
}
}
Figure 18: Example of Recurrence With Date Times
A.7. The "recurrence-time-zone-with-periods" Grouping
Figure 19 indicates a recurrence that occurs every 30 minutes and
lasts for 15 minutes from 9:00 AM to 5:00 PM and an extra two extra
occurrences at 6:00 PM and 6:30 PM with each lasting for 20 minutes
on 2025-12-01 (New York):
{
"example-sch-usage-7:recurrence-time-zone-with-periods": {
"recurrence-first": {
"start-time": "2025-12-01T09:00:00",
"duration": "PT00:15:00",
"time-zone-identifier": "America/New_York"
},
"frequency": "ietf-schedule:minutely",
"interval": 30,
"until": "2025-12-01T17:00:00Z",
"period": [
{
"period-start": "2025-12-01T18:00:00",
"duration": "PT00:20:00"
},
{
"period-start": "2025-12-01T18:30:00",
"duration": "PT00:20:00"
}
]
}
}
Figure 19: Example of Advanced Recurrence Schedule
A.8. The "icalendar-recurrence" Grouping
Figure 20 indicates 10 occurrences that occur at 8:00 AM (EST), (EST) every last
Saturday of the month starting in January 2024:
{
"example-sch-usage-8:icalendar-recurrence": {
"recurrence-first": {
"start-time": "2024-01-27T08:00:00",
"time-zone-identifier": "America/New_York"
},
"frequency": "ietf-schedule:monthly",
"count": 10,
"byday": [
{
"direction": [
-1
],
"weekday": "saturday"
}
]
}
}
Figure 20: Simple iCalendar Recurrence
Figure 21 is an example of a recurrence that occurs on the last
workday of the month until December 25, 2025, from starting January 1,
2025:
{
"example-sch-usage-8:icalendar-recurrence": {
"recurrence-first": {
"start-time": "2025-01-01"
},
"frequency": "ietf-schedule:monthly",
"until": "2025-12-25",
"byday": [
{
"weekday": "monday"
},
{
"weekday": "tuesday"
},
{
"weekday": "wednesday"
},
{
"weekday": "thursday"
},
{
"weekday": "friday"
}
],
"bysetpos": [
-1
]
}
}
Figure 21: Example of Advanced iCalendar Recurrence
Figure 22 indicates a recurrence that occurs every 20 minutes from
9:00 AM to 4:40 PM (UTC), with the exclusion of the occurrence
starting at 10:20 AM
being excluded on 2025-12-01:
{
"example-sch-usage-8:icalendar-recurrence": {
"recurrence-first": {
"start-time": "2025-12-01T09:00:00Z"
},
"until": "2025-12-01T16:40:00Z",
"frequency": "ietf-schedule:minutely",
"byminute": [
0,
20,
40
],
"byhour": [
9,
10,
11,
12,
13,
14,
15,
16
],
"exception-dates": [
"2025-12-01T10:20:00Z"
]
}
}
Figure 22: Example of Advanced iCalendar Recurrence with Exceptions
A.9. The "schedule-status" Grouping
Figure 23 indicates the scheduled recurrence status of Figure 22 at
the time of 12:15 PM, PM on 2025-12-01 (UTC):
{
"example-sch-usage-1:schedule-status": {
"state": "ietf-schedule:enabled",
"version": 1,
"schedule-type": "ietf-schedule:recurrence",
"counter": 9,
"last-occurrence": [
"2025-12-01T12:00:00Z"
],
"upcoming-occurrence": [
"2025-12-01T12:20:00Z"
]
}
}
Figure 23: Example of a Schedule Status
At the time of 12:15 PM, PM on 2025-12-01 (UTC), the recurring event
occurred at (note that the occurrence at 10:20 AM is excluded): 9:00,
9:20, 9:40, 10:00, 10:40, 11:00, 11:20, 11:40, and 12:00. The last
occurrence was at 12:00, and the upcoming one is at 12:20.
Appendix B. 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.
B.1. 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 module, which "uses" the "icalendar-recurrence"
grouping from the "ietf-schedule" module module, shows how a scheduled task
could be defined with different features used for options.
module example-scheduled-backup {
yang-version 1.1;
namespace "http://example.com/example-scheduled-backup";
prefix "ex-scback";
import ietf-inet-types {
prefix "inet";
}
import ietf-schedule {
prefix "schedule";
}
organization
"Example, Inc.";
contact
"Support at example.com";
description
"Example of a module defining a scheduled based scheduled-based backup
operation.";
revision "2023-01-19" {
description
"Initial Version."; version.";
reference
"RFC XXXX: 9922: A YANG Data Model for Scheduling.";
}
container scheduled-backup-tasks {
description
"A container for backing up all current running configuration configurations
on the device.";
list tasks {
key "task-id";
description
"The list of backing up tasks on this device.";
leaf task-id {
type string;
description
"The task identifier that uniquely identifies a scheduled
backup task.";
}
choice local-or-remote {
description
"Specifies whether the configuration to be backed up is
local or remote.";
case local {
description
"Configuration parameters for the backing up of local
devices.";
leaf local {
type empty;
description
"The parameter specifies the configuration to be
backed up is on the local device.";
}
}
case remote {
description
"Configuration parameters for backing up of remote
devices.";
leaf remote {
type inet:domain-name;
description
"The parameter specifies the remote device domain
name.";
}
}
}
container basic-recurrence-schedules {
if-feature schedule:basic-recurrence;
description
"Basic recurrence schedule specification, which only
applies when the schedule:basic-recurrence feature
is supported.";
leaf schedule-id {
type string;
description
"The schedule identifier for this recurrence rule.";
}
uses schedule:recurrence-basic {
refine frequency {
mandatory true;
}
refine interval {
default 1;
}
}
}
container icalendar-recurrence-schedules {
if-feature schedule:icalendar-recurrence;
description
"Basic recurrence schedule specification, which only
applies when the schedule:icalendar-recurrence feature
is supported.";
leaf schedule-id {
type string;
description
"The schedule identifier for this recurrence rule.";
}
uses schedule:icalendar-recurrence {
refine workweek-start {
default monday;
}
}
}
}
list schedule-set {
key "schedule-name";
description
"The list of schedule
"Schedule status list for the backup tasks.";
uses schedule:schedule-status-with-name;
}
}
}
B.2. 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., [RFC9657]. The following example module module,
which augments the "recurrence-utc-with-periods" grouping from "ietf-
schedule" module the
"ietf-schedule" module, shows how a scheduled attribute could be
defined.
module example-scheduled-link-bandwidth {
yang-version 1.1;
namespace "http://example.com/example-scheduled-link-bandwidth";
prefix "ex-scattr";
import ietf-network {
prefix "nw";
reference
"RFC 8345: A YANG Data Model for Network Topologies";
}
import ietf-schedule {
prefix "schedule";
reference
"RFC XXXX: 9922: A YANG Data Model for Scheduling";
}
organization
"Example, Inc.";
contact
"Support at example.com";
description
"Example of a module defining a scheduled link bandwidth.";
revision "2023-01-19" {
description
"Initial Version."; version.";
reference
"RFC XXXX: 9922: A YANG Data Model for Scheduling."; Scheduling";
}
grouping link-bandwidth-grouping {
description
"Grouping of the link bandwidth definition.";
leaf scheduled-bandwidth {
type uint64;
units "Kbps";
description
"Bandwidth values, expressed in kilobits per second.";
}
}
container link-attributes {
description
"Definition of link attributes.";
list link {
key "source-node destination-node";
description
"Definition of link attributes.";
leaf source-node {
type nw:node-id;
description
"Indicates the source node identifier.";
}
leaf destination-node {
type nw:node-id;
description
"Indicates the source node identifier.";
}
leaf default-bandwidth {
type uint64;
units "Kbps";
description
"Bandwidth value used for perdiods periods that don't match
a schedule.";
}
choice time-variant-type {
description
"Controls the schedule type.";
case period {
uses schedule:period-of-time;
}
case recurrence {
uses schedule:recurrence-utc-with-periods {
augment "period-timeticks" {
description
"Specifies the attributes inside each
period-timeticks
'period-timeticks' entry.";
uses link-bandwidth-grouping;
}
}
}
}
}
}
}
Figure 24 shows a configuration example in XML [W3C.XML1.0] of a
link's bandwidth that is scheduled between 2025-12-01 0:00 UTC to the
end of 2025-12-31 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 is not
covered by the period above is 1000 Kbps.
<?xml version="1.0" encoding="utf-8"?>
<link-attributes
xmlns="http://example.com/example-scheduled-link-bandwidth"
xmlns:schedule="urn:ietf:params:xml:ns:yang:ietf-schedule">
<link>
<source-node>ne1</source-node>
<destination-node>ne2</destination-node>
<default-bandwidth>1000</default-bandwidth>
<recurrence-first>
<utc-start-time>2025-12-01T01:00:00Z</utc-start-time>
</recurrence-first>
<frequency>schedule:daily</frequency>
<utc-until>2025-12-31T23:59:59Z</utc-until>
<period-timeticks>
<period-start>360000</period-start>
<period-end>2160000</period-end>
<scheduled-bandwidth>500</scheduled-bandwidth>
</period-timeticks>
<period-timeticks>
<period-start>7920000</period-start>
<period-end>8280000</period-end>
<scheduled-bandwidth>800</scheduled-bandwidth>
</period-timeticks>
</link>
</link-attributes>
Figure 24: Example of Scheduled Link's Bandwidth
Appendix C. Examples of Using the "ietf-schedule" Module for Scheduled
Use of Resources Framework
This section exemplifies how the architecture for supporting
scheduled reservation of Traffic Engineering (TE) resources in
[RFC8413] might leverage the "period-of-time" grouping defined in the
"ietf-schedule" module to implement scheduled use of resources.
The following example module shows how a scheduled link capacity
reservation could be defined.
module example-sch-capacity-res {
yang-version 1.1;
namespace "http://example.com/example-sch-capacity-res";
prefix "ex-schecaparev";
import ietf-network-topology {
prefix "nt";
}
import ietf-schedule {
prefix "schedule";
}
container link-capability-reservations {
list scheduled-link-capacity {
key "schedule-id";
leaf schedule-id {
type string;
}
leaf link-id {
type nt:link-id;
}
leaf reserved-capability {
type uint64;
units "Mbps";
}
uses schedule:period-of-time;
}
}
}
Section 4 of [RFC8413] defines the reference architecture for
scheduled use of resources, the resources. The service requester sends a request to
a Path Computation Element (PCE) and includes the parameters of the
Label Switched Path (LSP) that the requester wishes to supply, the supply. The
configuration example to provide the scheduled resource is shown in
Figure 25.
<?xml version="1.0" encoding="utf-8"?>
<link-capability-reservations
xmlns="http://example.com/example-sch-capacity-res"
xmlns:schedule="urn:ietf:params:xml:ns:yang:ietf-schedule">
<scheduled-link-capacity>
<schedule-id>1</schedule-id>
<link-id>1-2-1</link-id>
<reserved-capability>500</reserved-capability>
<period-start>2025-03-10T08:00:00Z</period-start>
<period-end>2025-03-10T09:00:00Z</period-end>
</scheduled-link-capacity>
<scheduled-link-capacity>
<schedule-id>2</schedule-id>
<link-id>2-1-1</link-id>
<reserved-capability>400</reserved-capability>
<period-start>2025-04-01T00:00:00Z</period-start>
<duration>PT09:00:00</duration>
</scheduled-link-capacity>
<scheduled-link-capacity>
<schedule-id>3</schedule-id>
<link-id>2-1-1</link-id>
<reserved-capability>500</reserved-capability>
<period-start>2025-04-01T09:00:00Z</period-start>
<period-end>2025-04-01T23:59:59Z</period-end>
</scheduled-link-capacity>
</link-capability-reservations>
Figure 25: Example of Scheduled Link's Bandwidth Reservation
Acknowledgments
This work is derived from the [I-D.ietf-opsawg-ucl-acl]. [YANG-NAC]. There is a desire from the
OPSAWG to see this model be module separately defined for wide use in
scheduling context.
Thanks to Adrian Farrel, Wei Pan, Tianran Zhou, Joe Clarke, Steve
Baillargeon, Dhruv Dhody, Robert Wilton, and Italo Busi for their
valuable comments and inputs to this work.
Many thanks to the authors of [I-D.ietf-tvr-schedule-yang],
[I-D.ietf-opsawg-scheduling-oam-tests], [YANG-SCHEDULE], [YANG-OAM], and
[I-D.ietf-netmod-eca-policy]
[NETMOD-ECA-POLICY] for the constructive discussion during IETF#118.
Other related efforts were explored in the past, e.g.,
[I-D.liu-netmod-yang-schedule].
[YANG-CONFIG-SCHEDULE].
Thanks to Reshad Rahman for the great YANG Doctors review, Mahesh
Jethanandani for the AD review, Per Andersson for the OPSDIR review,
Peter Yee for genart the GENART review, and Acee Lindem for the rtgdir RTGDIR
review.
Thanks to Éric Vyncke, Erik Kline, and Mike Bishop for the IESG
review.
Authors' Addresses
Qiufang Ma (editor)
Huawei
101 Software Avenue, Yuhua District
Jiangsu
210012
China
Email: maqiufang1@huawei.com
Qin Wu
Huawei
101 Software Avenue, Yuhua District
Jiangsu
210012
China
Email: bill.wu@huawei.com
Mohamed Boucadair (editor)
Orange
35000 Rennes
France
Email: mohamed.boucadair@orange.com
Daniel King
Lancaster University
United Kingdom
Email: d.king@lancaster.ac.uk