NETMOD Working Group M. Wang Internet-Draft Q. Wu Intended status: Standards Track Huawei Expires: May 20, 2020 C. Xie China Telecom I. Bryskin Individual X. Liu Volta Networks A. Clemm Futurewei H. Birkholz Fraunhofer SIT T. Zhou Huawei November 17, 2019 A YANG Data model for ECA Policy Management draft-wwx-netmod-event-yang-05 Abstract RFC8328 defines a policy-based management framework that allow definition of a data model to be used to represent high-level, possibly network-wide policies. Policy discussed in RFC8328 are classified into imperative policy and declarative policy, ECA policy is an typical example of imperative policy. This document defines an YANG data model for the ECA policy management. The ECA policy YANG provides the ability for the network management function (within a controller, an orchestrator, or a network element) to control the configuration and monitor state change and take simple and instant action on the network element when a trigger condition on the system state is met. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any Wang, et al. Expires May 20, 2020 [Page 1] Internet-Draft ECA YANG November 2019 time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on May 20, 2020. Copyright Notice Copyright (c) 2019 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions used in this document . . . . . . . . . . . . . . 4 2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 4 3. Objectives . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Relationship to YANG Push . . . . . . . . . . . . . . . . . . 5 5. Overview of ECA YANG Data Model . . . . . . . . . . . . . . . 6 5.1. ECA Policy Variable and Value . . . . . . . . . . . . . . 6 5.2. ECA Event . . . . . . . . . . . . . . . . . . . . . . . . 8 5.3. ECA Condition . . . . . . . . . . . . . . . . . . . . . . 9 5.4. ECA Action . . . . . . . . . . . . . . . . . . . . . . . 12 6. ECA YANG Model (Tree Structure) . . . . . . . . . . . . . . . 14 7. ECA YANG Module . . . . . . . . . . . . . . . . . . . . . . . 19 8. Security Considerations . . . . . . . . . . . . . . . . . . . 38 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 38 10. Acknowledges . . . . . . . . . . . . . . . . . . . . . . . . 39 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 39 12. Normative References . . . . . . . . . . . . . . . . . . . . 40 Appendix A. ECA Model Usage Example . . . . . . . . . . . . . . 41 Appendix B. Usage Example of Reusing Trigger-Grouping in smarter filter . . . . . . . . . . . . . . . . . . . . . . . 43 Appendix C. Changes between Revisions . . . . . . . . . . . . . 46 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 47 Wang, et al. Expires May 20, 2020 [Page 2] Internet-Draft ECA YANG November 2019 1. Introduction Network management consists of using one or multiple device-, technology-, service specific policies to influence management behavior within the system and make sure policies are enforced or executed correctly. [RFC8328] defines a policy-based management framework that allow definition of a data model to be used to represent high-level, possibly network-wide policies. Policies discussed in [RFC8328] are classified into imperative policy and declarative policy. Declarative policy specifies the goals to be achieved but not how to achieve those goals while imperative policy specifies when Events are triggered and what actions must be performed on the occurrence of an event. ECA policy is a typical example of imperative policy. Event-driven management of states of managed objects across a wide range of devices can be used to monitor state changes of managed objects or resource and automatic trigger of rules in response to events so as to better service assurance for customers and to provide rapid autonomic response that can exhibit self-management properties including self-configuration, self-healing, self-optimization, and self-protection. Following are some of the use-cases where such ECA Policy can be used: o To filter out of objects underneath a requested a subtree, the subscriber may use YANG Push smart filter to request the network server to monitor specific network management data objects and send updates only when the value falls within a certain range. o To filter out of objects underneath a requested a subtree, the subscriber may use YANG Push smart filter to request the network server to monitor specific network management data objects and send updates only when the value exceeds a certain threshold for the first time but not again until the threshold is cleared. o To provide rapid autonomic response that can exhibit self- management properties, the management system delegate event response behaviors (e.g., auto-recover from network failure) to the network device so that the network can react to network change as quickly as the event is detected. The event response behaviors delegation can be done using ECA policy,e.g., to preconfigure protection/ restoration capability on the network device. o To perform troubleshoot failures (i.e., fault verification and localization) and provide root cause analysis, the management system monitoring specific network management data objects may request the network device to export state information of a set of Wang, et al. Expires May 20, 2020 [Page 3] Internet-Draft ECA YANG November 2019 managed data objects when the value of monitored data object exceeds a certain threshold. o To set up an LSP and reserve resources within the network via NETCONF protocol operation, Path Computation API RPC model can be invoked to calculate a path meeting end-to-end network performance criteria. This document defines a ECA Policy management YANG data model. The ECA Policy YANG provides the ability for the network management function (within a controller, an orchestrator, or a network element) to control the configurations and monitor state parameters and take simple and instant action on the network element when a trigger condition on the system state is met. The data model in this document is designed to be compliant with the Network Management Datastore Architecture (NMDA) [RFC8342]. 2. Conventions used in this document 2.1. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. In this document, these words will appear with that interpretation only when in ALL CAPS. Lower case uses of these words are not to be interpreted as carrying [RFC2119] significance. This document uses the following terms: Error A deviation of a system from normal operation [RFC3877]. Fault Lasting error or warning condition [RFC3877]. Event Something that happens which may be of interest or trigger the invocation of the rule. A fault, an alarm, a change in network state, network security threat, hardware malfunction, buffer untilization crossing a threshold, network connection setup, an external input to the system, for example [RFC3877]. 2.2. Tree Diagrams Tree diagrams used in this document follow the notation defined in [RFC8340]. Wang, et al. Expires May 20, 2020 [Page 4] Internet-Draft ECA YANG November 2019 3. Objectives This section describes some of the design objectives for the ECA Policy management Data Model: o Clear and precise identification of Event types in the ECA Policy. o Clear and precise identification of managed object (i.e., policy variable) in the ECA Policy. o Allow nested ECA policy,e.g, one event to be able to call another nested event. o Allow the NETCONF server send updates only when the value falls within a certain range. o Allow the NETCONF server send updates only when the value exceeds a certain threshold for the first time but not again until the threshold is cleared. o Allow the NETCONF client monitor state changes of managed objects and maintain a continuous view of operational data and state and o Allow the NETCONF client optimize the system behavior across the whole network to meet objectives and provide some performance guarantees for network services. o Allow the the NETCONF server provide rapid autonomic response in the network device that can exhibit self-management properties including self-configuration, self-healing, self-optimization, and self-protection. 4. Relationship to YANG Push YANG-push mechanism provides a subscription service for updates from a datastore. And it supports two types of subscriptions which are distinguished by how updates are triggered: periodic and on-change. The On-change Push allow receivers to receive updates whenever changes to target managed objects occur. This document specifies a mechanism that provides three trigger conditions: o Existence: When a specific managed object appears,disappear or object change, the trigger fires, e.g. reserved ports are configured. o Boolean: The user can set the type of boolean operator (e.g. unequal, equal, less, less-or-equal, greater, greater-or-equal, Wang, et al. Expires May 20, 2020 [Page 5] Internet-Draft ECA YANG November 2019 etc) and preconfigured threshold value (e.g. Pre-configured threshold). If the value of a managed object meet Boolean conditions, the trigger fires, e.g., when the boolean operator type is 'less', the trigger will be fired if the value of managed object is less than the pre-configured Boolean value. o Threshold: The user can set the rising threshold,the falling threshold, the delta rising threshold, the delta falling threshold. A threshold test regularly compares the value of the monitored object with the threshold values, e.g., an event is triggered if the value of the monitored object is greater than or equal to the rising threshold or an event is triggered if the difference between the current measurement value and the previous measurement value is smaller than or equal to the delta falling threshold. In these three trigger conditions, existence with type set to object change is similar to on Push change. In addtion, the model defined in this document provides a method for closed loop network management automation which allows automatic trigger of rules in response to events so as to better service assurance for customers and to provide rapid autonomic response that can exhibit self-management properties including self-configuration, self-healing, self-optimization, and self-protection. The details of the usage example is described in Appendix A. 5. Overview of ECA YANG Data Model A ECA policy rule is read as: When event occurs in a situation where condition is true, then action is executed. Therefore ECA comprises three key elements: event, associated conditions, and associated actions. These three elements should be pushed down and configured on the NETCONF server by the NETCONF client. If the action is rejected by the server duing ECA policy execution, the action should be rolled back and cleaned up. 5.1. ECA Policy Variable and Value ECA policy variable generically represents information that changes (or "varies"), and that is set or evaluated by software. ECA policy Value is used for modeling values and constants used in policy conditions and actions. In policy, conditions and actions can abstract information as "policy variables" to be evaluated in logical expressions, or set by actions, e.g., the Policy Condition has the semantics "variable matches value" while Policy Action has the semantics "set variable to value". Wang, et al. Expires May 20, 2020 [Page 6] Internet-Draft ECA YANG November 2019 In ECA, two type of policy variables are defined, implicit variable and explicit variable. Explicit variables are bound to exact data object instance in the model while implicit variables are defined and evaluated outside of a model. Each ECA policy variable has the following attributes: o Name with Globally unique or ECA unique scope ; o Type either global or local; o Value data stored in the policy variable structured according to the PV type. This structure can be used to keep intermediate results/meta data during the execution of an ECA policy. The following operations are allowed with/on a PV: o initialize (with a constant/enum/identity); o set (with contents of another same type PV); o read (retrieve datastore contents pointed by the specified same type XPath/sub-tree); o write (modify configuration data in the datastore with the PV's content/value); o insert (PV's content into a same type list); o iterate (copy into PV one by one same type list elements) o function calls in a form of F(arg1,arg2,...), where F is an identity of a function from extendable function library, arg1,arg2,etc are PVs respectively, the function's input parameters, with the result returned in result policy variable. PVs could be used as input/output of an ECA invoked RPC and policy argument in the func calls. PVs could also be a source of information sent to the client in notification messages. PVs could be used in condition expressions The model structure for the Policy Variable is shown below: Wang, et al. Expires May 20, 2020 [Page 7] Internet-Draft ECA YANG November 2019 +--rw policy-variables | +--rw policy-variable* [name] | +--rw name string | +--rw type? identityref | +--rw explict-variable? yang:xpath1.0 | +--rw implict-variable? identityref | +--rw policy-value? union 5.2. ECA Event The ECA event are used to keep track of state of changes associated with one of multiple operational state data objects in the network device. Typical examples of ECA event include a fault, an alarm, a change in network state, network security threat, hardware malfunction, buffer utilization crossing a threshold, network connection setup, and an external input to the system. Each ECA Event has the following attributes: o event-name, the name of ECA event; o type, either one time or peridic scheduling; o group-id, which can be used to group a set of events that can be executed together,e.g., deliver a service or provide service assurance; o scheduled-time,configuration scheduling - scheduling one time or periodic. Nested-event are supported by allowing one event's trigger to reference other event's definitions using the call-event configuration. Called events apply their triggers and actions before returning to the calling event's trigger and resuming evaluation. If the called event is triggered, then it returns an effective boolean true value to the calling event. For the calling event, this is equivalent to a condition statement evaluating to a true value and evaluation of the event continues. All events specified in the ECA policy model are continuously monitored by the server. The model structure for the ECA Event is shown below: Wang, et al. Expires May 20, 2020 [Page 8] Internet-Draft ECA YANG November 2019 +--rw event* [event-name type] +--rw event-name string +--rw type identityref +--rw event-description? string +--rw group-id? group-type +--rw explict-variable* leafref +--rw clear? boolean +--rw scheduled-time | +--rw type? identityref | +--rw periodic | | +--rw interval uint32 | | +--rw start? yang:date-and-time | | +--rw end? yang:date-and-time | +--rw next-scheduled-time | +--rw month* string | +--rw day-of-month* uint8 | +--rw day-of-week* uint8 | +--rw hour* uint8 | +--rw minute* uint8 | +--rw second* uint8 | +--rw start? yang:date-and-time | +--rw end? yang:date-and-time +--ro last-event? -> /eca/event/event-name 5.3. ECA Condition ECA condition can be seen as a logical test that, if satisfied or evaluated to be true, cause the action to be carried out. In this model, ECA condition can be specified as logical combinations of the following three ECA condition expressions: o Existence: An existence ECA condition monitors and manages the absence, presence, and change of a data object, for example, interface status. When a monitored object is specified, the system reads the value of the monitored object regularly. * If the existence test type is Absent, the system triggers a network event and takes the specified action when the monitored object disappears. * If the existence test type is Present, the system triggers a network event and takes the specified action when the monitored object appears. * If the existence test type is Changed, the system triggers a network event and takes the specified action when the value of the monitored object changes. Wang, et al. Expires May 20, 2020 [Page 9] Internet-Draft ECA YANG November 2019 o Boolean: A Boolean test compares the value of the monitored object with the reference value and takes action according to the comparison result. The comparision hierarchy is logical hierarchies specified in a form of: or relation is one of the comparison operations from the set: ==, !=, >, <, >=, <= o The operation types include unequal, equal, less, lessorequal, greater, and greaterorequal. For example, if the comparison type is equal, an event is triggered when the value of the monitored object equals the reference value. The event will not be triggered again until the value becomes unequal and comes back to equal. o Threshold: A Threshold trigger condition regularly compares compares the value of the monitored object with the threshold values. * A rising network event is triggered if the value of the monitored object is greater than or equal to the rising threshold. * A falling network event is triggered if the value of the monitored object is smaller than or equal to the falling threshold. * A rising network event is triggered if the difference between the current measurement value and the previous measurement value is greater than or equal to the delta rising threshold. * A falling network event is triggered if the difference between the current measurement value and the previous measurement value is smaller than or equal to the delta falling threshold. * A falling network event is triggered if the values of the monitored object, the rising threshold, and the falling threshold are the same. * A falling network event is triggered if the delta rising threshold, the delta falling threshold, and the difference between the current sampled value and the previous sampled value is the same. Wang, et al. Expires May 20, 2020 [Page 10] Internet-Draft ECA YANG November 2019 If the value of the monitored object crosses a threshold multiple times in succession, the managed device triggers a network event only for the first crossing. In addition, logical operation type can be used to describe complex logical operations between different condition lists under the same event, for example, (condition A & condition B) or condition C. The model structure for the ECA Condition is shown below: Wang, et al. Expires May 20, 2020 [Page 11] Internet-Draft ECA YANG November 2019 +--rw condition* [name] | +--rw name string | +--rw condition-description? string | +--rw logical-operation-type? identityref | +--rw call-event? -> ../../event-name | +--rw (test)? | +--:(existences) | | +--rw existences | | +--rw type? enumeration | | +--rw policy-variable? leafref | +--:(boolean) | | +--rw boolean | | +--rw operator? operator | | +--rw policy-value | | | +--rw policy-argument | | | +--rw (argument)? | | | +--:(explict-variable) | | | | +--rw explict-variable? leafref | | | +--:(implict-variable) | | | | +--rw implict-variable? leafref | | | +--:(value) | | | +--rw policy-value? leafref | | +--rw policy-variable | | +--rw policy-argument | | +--rw (argument)? | | +--:(explict-variable) | | | +--rw explict-variable? leafref | | +--:(implict-variable) | | +--rw implict-variable? leafref | +--:(threshold) | +--rw threshold | +--rw rising-value? leafref | +--rw rising-policy-variable* leafref | +--rw falling-value? leafref | +--rw falling-policy-variable* leafref | +--rw delta-rising-value? leafref | +--rw delta-rising-policy-variable* leafref | +--rw delta-falling-value? leafref | +--rw delta-falling-policy-variable* leafref | +--rw startup? enumeration 5.4. ECA Action The action list consists of updates or invocations on local managed object attributes and a set of actions are defined as follows,which will be performed when the corresponding event is triggered: Wang, et al. Expires May 20, 2020 [Page 12] Internet-Draft ECA YANG November 2019 o (-re)configuration - modifying a configuration data in the conventional configuration datastore. o adding/removing event notify subscription (essentially, the same action as performed when a client explicitly adds/removes a subscription) o executing an RPC defined by a YANG module supported by the server (the same action as performed when a client interactively calls the RPC); o performing operations and function calls on PVs (such as assign, read, insert, iterate, etc); o sending one time log notification Multiple ECA Actions could be triggered by a single ECA event. Any given ECA Condition or Action may appear in more than one ECAs. The model structure for the ECA Action is shown below: +--rw actions +--rw action* [name] +--rw name string +--rw (action-type)? +--:(set) | +--rw set | +--rw policy-variable? leafref | +--rw value? +--:(logging) | +--rw logging | +--rw type? logging-type | +--rw policy-variable? leafref +--:(function-call) | +--rw function-call | +--rw function-type? identityref | +--rw policy-argument* [name] | | +--rw name string | | +--rw (argument)? | | +--:(explict-variable) | | | +--rw explict-variable? leafref | | +--:(implict-variable) | | | +--rw implict-variable? leafref | | +--:(value) | | +--rw policy-value? leafref | +--rw result | +--rw (argument)? Wang, et al. Expires May 20, 2020 [Page 13] Internet-Draft ECA YANG November 2019 | +--:(explict-variable) | | +--rw explict-variable? leafref | +--:(implict-variable) | | +--rw implict-variable? leafref | +--:(value) | +--rw policy-value? leafref +--:(rpc-call) +--rw rpc-call +--rw name? string +--rw input | +--rw policy-argument* [name] | +--rw name | | string | +--rw (argument)? | +--:(explict-variable) | | +--rw explict-variable? leafref | +--:(implict-variable) | | +--rw implict-variable? leafref | +--:(value) | +--rw policy-value? leafref +--rw output +--rw policy-argument* [name] +--rw name | string +--rw (argument)? +--:(explict-variable) | +--rw explict-variable? leafref +--:(implict-variable) | +--rw implict-variable? leafref +--:(value) +--rw policy-value? leafref 6. ECA YANG Model (Tree Structure) The following tree diagrams [RFC8340] provide an overview of the data model for the "ietf-eca" module. grouping start-end-grouping +-- start? yang:date-and-time +-- end? yang:date-and-time grouping existences-trigger +-- existences +-- type? enumeration +-- policy-variable? -> /policy-variables/policy-variable/name grouping boolean-trigger +-- boolean +-- operator? operator Wang, et al. Expires May 20, 2020 [Page 14] Internet-Draft ECA YANG November 2019 +-- policy-value | +-- policy-argument | +-- (argument)? | +--:(explict-variable) | | +-- explict-variable? leafref | +--:(implict-variable) | | +-- implict-variable? leafref | +--:(value) | +-- policy-value? leafref +-- policy-variable +-- policy-argument +-- (argument)? +--:(explict-variable) | +-- explict-variable? leafref +--:(implict-variable) +-- implict-variable? leafref grouping threshold-trigger +-- threshold +-- rising-value? | -> /policy-variables/policy-variable/policy-value +-- rising-policy-variable* | -> /policy-variables/policy-variable/name +-- falling-value? | -> /policy-variables/policy-variable/policy-value +-- falling-policy-variable* | -> /policy-variables/policy-variable/name +-- delta-rising-value? | -> /policy-variables/policy-variable/policy-value +-- delta-rising-policy-variable* | -> /policy-variables/policy-variable/name +-- delta-falling-value? | -> /policy-variables/policy-variable/policy-value +-- delta-falling-policy-variable* | -> /policy-variables/policy-variable/name +-- startup? enumeration grouping trigger-grouping +-- (test)? +--:(existences) | +-- existences | +-- type? enumeration | +-- policy-variable? | -> /policy-variables/policy-variable/name +--:(boolean) | +-- boolean | +-- operator? operator | +-- policy-value | | +-- policy-argument | | +-- (argument)? Wang, et al. Expires May 20, 2020 [Page 15] Internet-Draft ECA YANG November 2019 | | +--:(explict-variable) | | | +-- explict-variable? leafref | | +--:(implict-variable) | | | +-- implict-variable? leafref | | +--:(value) | | +-- policy-value? leafref | +-- policy-variable | +-- policy-argument | +-- (argument)? | +--:(explict-variable) | | +-- explict-variable? leafref | +--:(implict-variable) | +-- implict-variable? leafref +--:(threshold) +-- threshold +-- rising-value? leafref +-- rising-policy-variable* | -> /policy-variables/policy-variable/name +-- falling-value? leafref +-- falling-policy-variable* | -> /policy-variables/policy-variable/name +-- delta-rising-value? leafref +-- delta-rising-policy-variable* | -> /policy-variables/policy-variable/name +-- delta-falling-value? leafref +-- delta-falling-policy-variable* | -> /policy-variables/policy-variable/name +-- startup? enumeration module: ietf-eca +--rw policy-variables | +--rw policy-variable* [name] | +--rw name string | +--rw type? identityref | +--rw explict-variable? yang:xpath1.0 | +--rw implict-variable? identityref | +--rw policy-value? union +--rw eca +--rw event* [event-name type] +--rw event-name string +--rw type identityref +--rw event-description? string +--rw group-id? group-type +--rw explict-variable* leafref +--rw clear? boolean +--rw scheduled-time | +--rw type? identityref | +--rw periodic Wang, et al. Expires May 20, 2020 [Page 16] Internet-Draft ECA YANG November 2019 | | +--rw interval uint32 | | +--rw start? yang:date-and-time | | +--rw end? yang:date-and-time | +--rw next-scheduled-time | +--rw month* string | +--rw day-of-month* uint8 | +--rw day-of-week* uint8 | +--rw hour* uint8 | +--rw minute* uint8 | +--rw second* uint8 | +--rw start? yang:date-and-time | +--rw end? yang:date-and-time +--ro last-event? -> /eca/event/event-name +--ro last-condition? -> /eca/event/condition/name +--ro last-action? | -> /eca/event/actions/action/name +--rw condition* [name] | +--rw name string | +--rw condition-description? string | +--rw logical-operation-type? identityref | +--rw call-event? -> ../../event-name | +--rw (test)? | +--:(existences) | | +--rw existences | | +--rw type? enumeration | | +--rw policy-variable? leafref | +--:(boolean) | | +--rw boolean | | +--rw operator? operator | | +--rw policy-value | | | +--rw policy-argument | | | +--rw (argument)? | | | +--:(explict-variable) | | | | +--rw explict-variable? leafref | | | +--:(implict-variable) | | | | +--rw implict-variable? leafref | | | +--:(value) | | | +--rw policy-value? leafref | | +--rw policy-variable | | +--rw policy-argument | | +--rw (argument)? | | +--:(explict-variable) | | | +--rw explict-variable? leafref | | +--:(implict-variable) | | +--rw implict-variable? leafref | +--:(variation) | +--rw variation | +--rw rising-value? leafref Wang, et al. Expires May 20, 2020 [Page 17] Internet-Draft ECA YANG November 2019 | +--rw rising-policy-variable* leafref | +--rw falling-value? leafref | +--rw falling-policy-variable* leafref | +--rw delta-rising-value? leafref | +--rw delta-rising-policy-variable* leafref | +--rw delta-falling-value? leafref | +--rw delta-falling-policy-variable* leafref | +--rw startup? | enumeration +--rw actions +--rw action* [name] +--rw name string +--rw (action-type)? +--:(set) | +--rw set | +--rw policy-variable? leafref | +--rw value? +--:(logging) | +--rw logging | +--rw type? logging-type | +--rw policy-variable? leafref +--:(function-call) | +--rw function-call | +--rw function-type? identityref | +--rw policy-argument* [name] | | +--rw name string | | +--rw (argument)? | | +--:(explict-variable) | | | +--rw explict-variable? leafref | | +--:(implict-variable) | | | +--rw implict-variable? leafref | | +--:(value) | | +--rw policy-value? leafref | +--rw result | +--rw (argument)? | +--:(explict-variable) | | +--rw explict-variable? leafref | +--:(implict-variable) | | +--rw implict-variable? leafref | +--:(value) | +--rw policy-value? leafref +--:(rpc-call) +--rw rpc-call +--rw name? string +--rw input | +--rw policy-argument* [name] | +--rw name | | string Wang, et al. Expires May 20, 2020 [Page 18] Internet-Draft ECA YANG November 2019 | +--rw (argument)? | +--:(explict-variable) | | +--rw explict-variable? leafref | +--:(implict-variable) | | +--rw implict-variable? leafref | +--:(value) | +--rw policy-value? leafref +--rw output +--rw policy-argument* [name] +--rw name | string +--rw (argument)? +--:(explict-variable) | +--rw explict-variable? leafref +--:(implict-variable) | +--rw implict-variable? leafref +--:(value) +--rw policy-value? leafref 7. ECA YANG Module file "ietf-eca@2019-10-28.yang" module ietf-eca { yang-version 1.1; namespace "urn:ietf:params:xml:ns:yang:ietf-eca"; prefix eca; import ietf-yang-types { prefix yang; } organization "IETF xxx Working Group"; contact "Zitao Wang: wangzitao@huawei.com Qin Wu: bill.wu@huawei.com"; description " This module contains YANG specifications for ECA Policy management. Copyright (c) 2019 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 Simplified 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). Wang, et al. Expires May 20, 2020 [Page 19] Internet-Draft ECA YANG November 2019 This version of this YANG module is part of RFC xxxx; see the RFC itself for full legal notices."; revision 2019-11-11 { description "Initial revision."; reference "foo"; } identity variable-type { description "base variable type"; } identity global-explict { base variable-type; description "Identity for global explict variable"; } identity global-implict { base variable-type; description "Identity for global explict variablae"; } identity local-explict { base variable-type; description "Identity for local explict variable"; } identity local-implict { base variable-type; description "Identity for local implict variable"; } identity function-type { description "Possible values are: plus, minus, mult, divide, remain."; } identity logical-operation-type { description "Possible values are: not, or, and."; } identity policy-variable-type { description "Possible values are: Wang, et al. Expires May 20, 2020 [Page 20] Internet-Draft ECA YANG November 2019 boolean, int32, int64, uint32, uint64, string, etc."; } identity event-type { description "Base identity for event type"; } identity frequency { description "Base identity for frequency"; } identity periodic { base frequency; description "Identity for periodic trigger"; } identity scheduling { base frequency; description "Identity for scheduling trigger"; } identity logging { description "Base identity for logging action"; } identity logging-notification { base logging; description "Logging for event notification"; } identity logging-set { base logging; description "Logging for reset values"; } typedef logging-type { type identityref { base logging; } description "Logging types"; Wang, et al. Expires May 20, 2020 [Page 21] Internet-Draft ECA YANG November 2019 } typedef group-type { type string; description "Group type"; } grouping start-end-grouping { description "A grouping that provides start and end times for Event objects."; leaf start { type yang:date-and-time; description "The date and time when the Event object starts to create triggers."; } leaf end { type yang:date-and-time; description "The date and time when the Event object stops to create triggers. It is generally a good idea to always configure an end time and to refresh the end time as needed to ensure that agents that lose connectivity to their Controller do not continue executing Schedules forever."; } } typedef operator { type enumeration { enum unequal { description "Indicates that the comparision type is unequal to."; } enum equal { description "Indicates that the comparision type is equal to."; } enum less { description "Indicates that the comparision type is less than."; } enum less-or-equal { description "Indicates that the comparision type is less than Wang, et al. Expires May 20, 2020 [Page 22] Internet-Draft ECA YANG November 2019 or equal to."; } enum greater { description "Indicates that the comparision type is greater than."; } enum greater-or-equal { description "Indicates that the comparision type is greater than or equal to."; } } description "definition of the operator"; } grouping existences-trigger { description "A grouping that provides existence trigger"; container existences { leaf type { type enumeration { enum match { description "march"; } enum mismatch { description "mismatch"; } } description "existence type, variable match the value or variable mismatch the value"; } leaf policy-variable { type leafref { path "/policy-variables/policy-variable/name"; } description "Policy variable"; } description "Container for existence"; } } grouping boolean-trigger { description "A grouping that provides boolean trigger"; container boolean { Wang, et al. Expires May 20, 2020 [Page 23] Internet-Draft ECA YANG November 2019 leaf operator { type operator; description "Comparison type."; } container policy-value { container policy-argument { choice argument { case explict-variable { leaf explict-variable { type leafref { path "/policy-variables/policy-variable/explict-variable"; } description "explict variable"; } } case implict-variable { leaf implict-variable { type leafref { path "/policy-variables/policy-variable/implict-variable"; } description "implict variable"; } } case value { leaf policy-value { type leafref { path "/policy-variables/policy-variable/policy-value"; } description "policy value"; } } description "Choice one argument format"; } description "Cotainer for policy argument"; } description "Container for policy value"; } container policy-variable { container policy-argument { choice argument { case explict-variable { Wang, et al. Expires May 20, 2020 [Page 24] Internet-Draft ECA YANG November 2019 leaf explict-variable { type leafref { path "/policy-variables/policy-variable/explict-variable"; } description "explict variable"; } } case implict-variable { leaf implict-variable { type leafref { path "/policy-variables/policy-variable/implict-variable"; } description "implict variable"; } } description "Choice one argument format"; } description "Cotainer for policy argument"; } description "Container for policy variable"; } description "Container for boolean test."; } } grouping threshold-trigger { description "A grouping that provides threshold trigger"; container threshold { leaf rising-value { type leafref { path "/policy-variables/policy-variable/policy-value"; } description "Sets the rising threshold to the specified value, when the current sampled value is greater than or equal to this threshold, and the value at the last sampling interval was less than this threshold, the event is triggered. "; } leaf-list rising-policy-variable { type leafref { path "/policy-variables/policy-variable/name"; Wang, et al. Expires May 20, 2020 [Page 25] Internet-Draft ECA YANG November 2019 } description "List for target variable."; } leaf falling-value { type leafref { path "/policy-variables/policy-variable/policy-value"; } description "Sets the falling threshold to the specified value."; } leaf-list falling-policy-variable { type leafref { path "/policy-variables/policy-variable/name"; } description "List for target variable."; } leaf delta-rising-value { type leafref { path "/policy-variables/policy-variable/policy-value"; } description "Sets the delta rising threshold to the specified value."; } leaf-list delta-rising-policy-variable { type leafref { path "/policy-variables/policy-variable/name"; } description "List for target variable."; } leaf delta-falling-value { type leafref { path "/policy-variables/policy-variable/policy-value"; } description "Sets the delta falling threshold to the specified value."; } leaf-list delta-falling-policy-variable { type leafref { path "/policy-variables/policy-variable/name"; } description "List for target variable."; } leaf startup { type enumeration { Wang, et al. Expires May 20, 2020 [Page 26] Internet-Draft ECA YANG November 2019 enum rising { description "If the first sample after this managed object becomes active is greater than or equal to 'rising-value' and the 'startup' is equal to 'rising' then one threshold rising event is triggered for that managed object."; } enum falling { description "If the first sample after this managed object becomes active is less than or equal to 'falling-value' and the 'startup' is equal to 'falling' then one threshold falling event is triggered for that managed object."; } enum rising-or-falling { description "That event may be triggered when the 'startup' is equal to 'rising-or-falling'. 'rising-or-falling' indicate the state value of the managed object may less than or greater than the specified thrshold value."; } } description "Startup setting."; } description "Container for the threshold trigger condition. Note that the threshold here may change over time or the state value changes in either ascend order or descend order."; } } grouping trigger-grouping { description "A grouping that provides event trigger."; choice test { description "Choice test"; case existences { uses existences-trigger; } case boolean { uses boolean-trigger; } Wang, et al. Expires May 20, 2020 [Page 27] Internet-Draft ECA YANG November 2019 case threshold { uses threshold-trigger; } } } container policy-variables { list policy-variable { key "name"; leaf name { type string; description "Policy variable name"; } leaf type { type identityref { base variable-type; } description "Policy variable type"; } leaf explict-variable { type yang:xpath1.0; description "Explict policy variable"; } leaf implict-variable { type identityref { base policy-variable-type; } description "A common policy variable type, defined as an identity."; } leaf policy-value { type union { type yang:xpath1.0; type yang:object-identifier; type yang:uuid; type string; type boolean; type int32; type int64; type uint32; type uint64; } description "Policy value"; Wang, et al. Expires May 20, 2020 [Page 28] Internet-Draft ECA YANG November 2019 } description "List for policy variable"; } description "Policy variables"; } container eca { list event { key "event-name type"; leaf event-name { type string; description "Event name"; } leaf type { type identityref { base event-type; } description "Type of event"; } leaf event-description { type string; description "Event description"; } leaf group-id { type group-type; description "Group Identifier"; } leaf-list explict-variable { type leafref { path "/policy-variables/policy-variable/explict-variable"; } description "Explict variable"; } leaf clear { type boolean; default "false"; description "A flag indicate whether the event be closed"; } container scheduled-time { leaf type { type identityref { Wang, et al. Expires May 20, 2020 [Page 29] Internet-Draft ECA YANG November 2019 base frequency; } description "Type of scheduled-time"; } container periodic { when "derived-from-or-self(../type, 'periodic')"; description "A periodic timing object triggers periodically according to a regular interval."; leaf interval { type uint32 { range "1..max"; } units "seconds"; mandatory true; description "The number of seconds between two triggers generated by this periodic timing object."; } uses start-end-grouping; } container next-scheduled-time { when "derived-from-or-self(../type, 'scheduling')"; description "A scheduling timing object triggers."; leaf-list month { type string; description "A set of months at which this scheduling timing will trigger."; } leaf-list day-of-month { type uint8 { range "0..59"; } description "A set of days of the month at which this scheduling timing will trigger."; } leaf-list day-of-week { type uint8 { range "0..59"; } description "A set of weekdays at which this scheduling timing will trigger."; } Wang, et al. Expires May 20, 2020 [Page 30] Internet-Draft ECA YANG November 2019 leaf-list hour { type uint8 { range "0..59"; } description "A set of hours at which the scheduling timing will trigger."; } leaf-list minute { type uint8 { range "0..59"; } description "A set of minutes at which this scheduling timing will trigger."; } leaf-list second { type uint8 { range "0..59"; } description "A set of seconds at which this calendar timing will trigger."; } uses start-end-grouping; } description "Container for frequency"; } leaf last-event { type leafref { path "/eca/event/event-name"; } config false; description "The reference to a event last executed or being executed."; } leaf last-condition { type leafref { path "/eca/event/condition/name"; } config false; description "The reference to a condition last executed or being executed."; } leaf last-action { Wang, et al. Expires May 20, 2020 [Page 31] Internet-Draft ECA YANG November 2019 type leafref { path "/eca/event/actions/action/name"; } config false; description "The reference to aa action last executed or being executed."; } list condition { key "name"; leaf name { type string; description "Trigger name"; } leaf condition-description { type string; description "Trigger description"; } leaf logical-operation-type { type identityref { base logical-operation-type; } description "The logical operation type."; } leaf call-event { type leafref { path "../../event-name"; } description "This leaf call sub-event."; } uses trigger-grouping; description "List for trigger"; } container actions { list action { key "name"; leaf name { type string; description "Action Name"; } choice action-type { description Wang, et al. Expires May 20, 2020 [Page 32] Internet-Draft ECA YANG November 2019 "Choice one action type"; case set { container set { leaf policy-variable { type leafref { path "/policy-variables/policy-variable/name"; } description "The target objects"; } anydata value { description "Inline set content."; } description "Set a value to the target"; } } case logging { container logging { leaf type { type logging-type; description "Specifies the log action"; } leaf policy-variable { type leafref { path "/policy-variables/policy-variable/name"; } description "The target objects"; } description "Specifies the log action"; } } case function-call { container function-call { description "The operation is to call a function, which is of one of a few basic predefined types, such as plus, minus, multiply, devide, or remainder."; leaf function-type { type identityref { base function-type; } description "One of the predefined basic function types, such as Wang, et al. Expires May 20, 2020 [Page 33] Internet-Draft ECA YANG November 2019 plus, minus, multiply, devide, or remainder."; } list policy-argument { key "name"; leaf name { type string; description "Policy argument name"; } choice argument { case explict-variable { leaf explict-variable { type leafref { path "/policy-variables/policy-variable/explict-variable"; } description "explict variable"; } } case implict-variable { leaf implict-variable { type leafref { path "/policy-variables/policy-variable/implict-variable"; } description "implict variable"; } } case value { leaf policy-value { type leafref { path "/policy-variables/policy-variable/policy-value"; } description "policy value"; } } description "Choice one argument format"; } description "List for policy argument"; } container result { choice argument { case explict-variable { leaf explict-variable { type leafref { Wang, et al. Expires May 20, 2020 [Page 34] Internet-Draft ECA YANG November 2019 path "/policy-variables/policy-variable/explict-variable"; } description "explict variable"; } } case implict-variable { leaf implict-variable { type leafref { path "/policy-variables/policy-variable/implict-variable"; } description "implict variable"; } } case value { leaf policy-value { type leafref { path "/policy-variables/policy-variable/policy-value"; } description "policy value"; } } description "Choice one argument format"; } description "Container for result"; } } } case rpc-call { container rpc-call { leaf name { type string; description "The name of the YANG RPC or YANG action to be called."; } container input { list policy-argument { key "name"; leaf name { type string; description "Policy argument name"; } Wang, et al. Expires May 20, 2020 [Page 35] Internet-Draft ECA YANG November 2019 choice argument { case explict-variable { leaf explict-variable { type leafref { path "/policy-variables/policy-variable/explict-variable"; } description "explict variable"; } } case implict-variable { leaf implict-variable { type leafref { path "/policy-variables/policy-variable/implict-variable"; } description "implict variable"; } } case value { leaf policy-value { type leafref { path "/policy-variables/policy-variable/policy-value"; } description "policy value"; } } description "Choice one argument format"; } description "List for policy argument"; } description "Container for input"; } container output { list policy-argument { key "name"; leaf name { type string; description "Policy argument name"; } choice argument { case explict-variable { leaf explict-variable { Wang, et al. Expires May 20, 2020 [Page 36] Internet-Draft ECA YANG November 2019 type leafref { path "/policy-variables/policy-variable/explict-variable"; } description "explict variable"; } } case implict-variable { leaf implict-variable { type leafref { path "/policy-variables/policy-variable/implict-variable"; } description "implict variable"; } } case value { leaf policy-value { type leafref { path "/policy-variables/policy-variable/policy-value"; } description "policy value"; } } description "Choice one argument format"; } description "List for policy argument"; } description "Container for output"; } description "Container for rpc call"; } } } description "List for actions"; } description "Container for Actions"; } description "List for Events"; } Wang, et al. Expires May 20, 2020 [Page 37] Internet-Draft ECA YANG November 2019 description "YANG data module for defining event triggers and actions for network management purposes"; } } 8. Security Considerations The YANG modules defined in this document MAY be accessed via the RESTCONF protocol [RFC8040] or NETCONF protocol ([RFC6241]). The lowest RESTCONF or NETCONF layer requires that the transport-layer protocol provides both data integrity and confidentiality, see Section 2 in [RFC8040] and [RFC6241]. The lowest NETCONF layer is the secure transport layer, and the mandatory-to-implement secure transport is Secure Shell (SSH)[RFC6242] . The lowest RESTCONF layer is HTTPS, and the mandatory-to-implement secure transport is TLS [RFC5246]. The NETCONF access control model [RFC6536] 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. There are a number of data nodes defined in this YANG module that are writable/creatable/deletable (i.e., config true, which is the default). These data nodes may be considered sensitive or vulnerable in some network environments. Write operations (e.g., edit-config) to these data nodes without proper protection can have a negative effect on network operations. These are the subtrees and data nodes and their sensitivity/vulnerability: o /eca/event/event-name o /eca/policy-variables/policy-variable/name o /eca/event/actions/action/name o /eca/event/condition/name 9. IANA Considerations This document registers two URIs in the IETF XML registry [RFC3688]. Following the format in [RFC3688], the following registrations are requested to be made: Wang, et al. Expires May 20, 2020 [Page 38] Internet-Draft ECA YANG November 2019 --------------------------------------------------------------------- URI: urn:ietf:params:xml:ns:yang:ietf-eca Registrant Contact: The IESG. XML: N/A, the requested URI is an XML namespace. --------------------------------------------------------------------- This document registers one YANG module in the YANG Module Names registry [RFC6020]. --------------------------------------------------------------------- Name: ietf-eca Namespace: urn:ietf:params:xml:ns:yang:ietf-eca Prefix: eca Reference: RFC xxxx --------------------------------------------------------------------- 10. Acknowledges This work has benefited from the discussions of ECA Policy over the years. In particular, the SUPA project [ https://datatracker.ietf.org/wg/supa/about/ ] provided approaches to express high-level, possibly network-wide policies to a network management function (within a controller, an orchestrator, or a network element). Igor Bryskin, Xufeng Liu, Alexander Clemm, Henk Birkholz, Tianran Zhou contributed to an earlier version of [GNCA]. We would like to thank the authors of that document on event response behaviors delegation for material that assisted in thinking that helped improve this document. 11. Contributors Nicola Sambo Scuola Superiore Sant'Anna Via Moruzzi 1 Pisa 56124 Italy Email: nicola.sambo@sssup.it Giuseppe Fioccola Huawei Technologies Riesstrasse, 25 Munich 80992 Germany Email: giuseppe.fioccola@huawei.com Wang, et al. Expires May 20, 2020 [Page 39] Internet-Draft ECA YANG November 2019 12. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", March 1997. [RFC2981] Kavasseri, R., Ed., "Event MIB", RFC 2981, DOI 10.17487/RFC2981, October 2000, . [RFC3460] Moore, B., Ed., "Policy Core Information Model (PCIM) Extensions", RFC 3460, DOI 10.17487/RFC3460, January 2003, . [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, DOI 10.17487/RFC3688, January 2004, . [RFC6020] Bjorklund, M., Ed., "YANG - A Data Modeling Language for the Network Configuration Protocol (NETCONF)", RFC 6020, DOI 10.17487/RFC6020, October 2010, . [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, . [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, . [RFC6370] Bocci, M., Swallow, G., and E. Gray, "MPLS Transport Profile (MPLS-TP) Identifiers", RFC 6370, DOI 10.17487/RFC6370, September 2011, . [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, DOI 10.17487/RFC6536, March 2012, . [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", RFC 7950, DOI 10.17487/RFC7950, August 2016, . [RFC7952] Lhotka, L., "Defining and Using Metadata with YANG", RFC 7952, DOI 10.17487/RFC7952, August 2016, . Wang, et al. Expires May 20, 2020 [Page 40] Internet-Draft ECA YANG November 2019 [RFC8328] Liu, W., Xie, C., Strassner, J., Karagiannis, G., Klyus, M., Bi, J., Cheng, Y., and D. Zhang, "Policy-Based Management Framework for the Simplified Use of Policy Abstractions (SUPA)", RFC 8328, DOI 10.17487/RFC8328, March 2018, . Appendix A. ECA Model Usage Example +---------------------------+ | Management System | +---------------------------+ | ECA | Model | | V +----------------------^-----+ | Managed Device | | | | | | //--\\ Condition--+ | | | Event| / \ | | | |----->|Actions | | \\--// \ / | | ---- | +----------------------------+ For Example: The management system push down one ECA policy to control interface behavior in the managed device that supports NETCONF protocol operation. The explicit policy variable of Event "interface-state-monitoring" is set to "/if:interfaces/if:interface[if:name='eth0']", the trigger list contains two conditions: 1)receiver received a push-change- update notification; 2) the value of "in-errors" of interface[name='eth0'] exceeded the pre-configured threshold. When these conditions are met, corresponding action will be performed, i.e. disable interface[name='eth0']. The XML examples are shown as below: 2017-10-25T08:22:33.44Z 89 Wang, et al. Expires May 20, 2020 [Page 41] Internet-Draft ECA YANG November 2019 0 edit1 replace /ietf-interfaces:interfaces eth0 up interface-state-monitoring interface-exception /if:interfaces/if:interface[if:name='eth0'] 10m state-push-change received yang push \changed notification /yp:notification/yp:push-change-update/yp:id[id=89]\ /yp:datastore-changes/.../yp:target="/ietf-interfaces:interfaces='eth0'\ evaluate-in-errors interface-state-chang evaluate the number of the packets that contained errors greater-or-equal 100 Wang, et al. Expires May 20, 2020 [Page 42] Internet-Draft ECA YANG November 2019 /if:interfaces/if:interface[if:name='eth0']\ /if:statistic/if:in-errors foo /if:interfaces/if:interface[if:name='eth0'] eth0 false Appendix B. Usage Example of Reusing Trigger-Grouping in smarter filter The "ietf-eca.yang" module defines a set of groupings for a generic condition expression. It is intended that these groupings can be reused by other models that require the trigger conditions, for example, in some subscription and notification cases, many applications do not require every update, only updates that are of certain interest. The following example describe how to reuse the "ietf-eca" module to define the subscription and notification smarter filter. Wang, et al. Expires May 20, 2020 [Page 43] Internet-Draft ECA YANG November 2019 import ietf-subscribed-notifications { prefix sn; } import ietf-eca { prefix eca; } augment "/sn:subscriptions/sn:subscription" { description "add the smart filter container"; container smart-filter { description "It concludes filter configurations"; uses eca:trigger-grouping; } } The tree diagrams: Wang, et al. Expires May 20, 2020 [Page 44] Internet-Draft ECA YANG November 2019 module: ietf-smart-filter augment /sn:subscriptions/sn:subscription: +--rw smart-filter +-- (test)? +--:(existences) | +-- existences | +-- type? enumeration | +-- policy-variable? | -> /policy-variables/policy-variable/name +--:(boolean) | +-- boolean | +-- operator? operator | +-- policy-value | | +-- policy-argument | | +-- (argument)? | | +--:(explict-variable) | | | +-- explict-variable? leafref | | +--:(implict-variable) | | | +-- implict-variable? leafref | | +--:(value) | | +-- policy-value? leafref | +-- policy-variable | +-- policy-argument | +-- (argument)? | +--:(explict-variable) | | +-- explict-variable? leafref | +--:(implict-variable) | +-- implict-variable? leafref +--:(threshold) +-- threshold +-- rising-value? leafref +-- rising-policy-variable* | -> /policy-variables/policy-variable/name +-- falling-value? leafref +-- falling-policy-variable* | -> /policy-variables/policy-variable/name +-- delta-rising-value? leafref +-- delta-rising-policy-variable* | -> /policy-variables/policy-variable/name +-- delta-falling-value? leafref +-- delta-falling-policy-variable* | -> /policy-variables/policy-variable/name +-- startup? enumeration Wang, et al. Expires May 20, 2020 [Page 45] Internet-Draft ECA YANG November 2019 Appendix C. Changes between Revisions v04 -v05 o Harmonize with draft-bryskin and add additional attributes in the models (e.g., policy variable, func call enhancement, rpc execution); o ECA conditions part harmonization; o ECA Event, Condition, Action, Policy Vriable and Value definition; o Change ietf-event.yang into ietf-eca.yang and remove ietf-event- trigger.yang v02 - v03 o Usage Example Update: add an usage example to introduce how to reuse the ietf-event-trigger module to define the subscription- notification smarter filter. v01 - v02 o Introduce the group-id which allow group a set of events that can be executed together o Change threshold trigger condition into variation trigger condition to further clarify the difference between boolean trigger condition and variation trigger condition. o Module structure optimization. o Usage Example Update. v00 - v01 o Separate ietf-event-trigger.yang from Event management modeland ietf-event.yang and make it reusable in other YANG models. o Clarify the difference between boolean trigger condition and threshold trigger condition. o Change evt-smp-min and evt-smp-max into min-data-object and max- data-object in the data model. Wang, et al. Expires May 20, 2020 [Page 46] Internet-Draft ECA YANG November 2019 Authors' Addresses Michael Wang Huawei Technologies,Co.,Ltd 101 Software Avenue, Yuhua District Nanjing 210012 China Email: wangzitao@huawei.com Qin Wu Huawei 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China Email: bill.wu@huawei.com Chongfeng Xie China Telecom Email: xiechf@ctbri.com.cn Igor Bryskin Individual Email: i_bryskin@yahoo.com Xufeng Liu Volta Networks Email: xufeng.liu.ietf@gmail.com Alexander Clemm Futurewei Email: ludwig@clemm.org Henk Birkholz Fraunhofer SIT Email: henk.birkholz@sit.fraunhofer.de Wang, et al. Expires May 20, 2020 [Page 47] Internet-Draft ECA YANG November 2019 Tianran Zhou Huawei Email: zhoutianran@huawei.com Wang, et al. Expires May 20, 2020 [Page 48]