NETCONF A. Gonzalez Prieto Internet-Draft A. Clemm Intended status: Standards Track E. Voit Expires: December 17, 2016 E. Nilsen-Nygaard A. Tripathy Cisco Systems S. Chisholm Ciena H. Trevino Cisco Systems June 15, 2016 NETCONF Support for Event Notifications draft-gonzalez-netconf-event-notifications-00 Abstract This document defines the support of [event-notifications] by the Network Configuration protocol (NETCONF). [event-notifications] describes capabilities and operations for providing asynchronous message notification delivery. This document discussed how to provide them on top of NETCONF. The capabilities and operations defined between this document and [event-notifications] are intended to obsolete RFC 5277. 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 http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on December 17, 2016. Copyright Notice Copyright (c) 2016 IETF Trust and the persons identified as the document authors. All rights reserved. Gonzalez Prieto, et al. Expires December 17, 2016 [Page 1] Internet-Draft NETCONF-notifications June 2016 This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://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 . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 1.2. Solution Overview . . . . . . . . . . . . . . . . . . . . 5 2. Solution . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1. Event Streams . . . . . . . . . . . . . . . . . . . . . . 5 2.2. Event Stream Discovery . . . . . . . . . . . . . . . . . 6 2.3. Default Event Stream . . . . . . . . . . . . . . . . . . 8 2.4. Creating a Subscription . . . . . . . . . . . . . . . . . 8 2.5. Establishing a Subscription . . . . . . . . . . . . . . . 11 2.6. Modifying a Subscription . . . . . . . . . . . . . . . . 15 2.7. Deleting a Subscription . . . . . . . . . . . . . . . . . 20 2.8. Configured Subscriptions . . . . . . . . . . . . . . . . 23 2.9. Event (Data Plane) Notifications . . . . . . . . . . . . 31 2.10. Control Plane Notifications . . . . . . . . . . . . . . . 33 3. Backwards Compatibility . . . . . . . . . . . . . . . . . . . 43 3.1. Capabilities . . . . . . . . . . . . . . . . . . . . . . 43 3.2. Stream Discovery . . . . . . . . . . . . . . . . . . . . 44 4. Security Considerations . . . . . . . . . . . . . . . . . . . 44 5. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 45 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 45 6.1. Normative References . . . . . . . . . . . . . . . . . . 45 6.2. Informative References . . . . . . . . . . . . . . . . . 46 Appendix A. Issues being worked and resolved . . . . . . . . . . 46 A.1. Unresolved Issues . . . . . . . . . . . . . . . . . . . . 46 A.2. Agreement in principal . . . . . . . . . . . . . . . . . 46 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 47 1. Introduction [RFC6241] can be conceptually partitioned into four layers: Gonzalez Prieto, et al. Expires December 17, 2016 [Page 2] Internet-Draft NETCONF-notifications June 2016 Layer Example +-------------+ +-------------------------------------------+ | Content | | Configuration data | +-------------+ +-------------------------------------------+ | | +-------------+ +-------------------------------------------+ | Operations | |, , | +-------------+ +-------------------------------------------+ | | | +-------------+ +-----------------------------+ | | RPC | | , | | +-------------+ +-----------------------------+ | | | | +-------------+ +-------------------------------------------+ | Transport | | BEEP, SSH, SSL, console | | Protocol | | | +-------------+ +-------------------------------------------+ Figure 1: NETCONF layer architecture This document defines mechanisms that provide an asynchronous message notification delivery service for the NETCONF protocol [RFC6241] based on [event-notifications]. This is an optional capability built on top of the base NETCONF definition. [event-notifications] and this document enhance the capabilities of RFC 5277 while maintaining backwards capability with existing implementations. It is intended that a final version of this document might obsolete [RFC5277]. The enhancements over [RFC5277] include the ability to terminate subscriptions without terminating the client session, to modify existing subscriptions, and to have multiple subscriptions on a NETCONF session. These enhancements do not affect [RFC5277] clients that do not support these particular subscription requirements. [event-notifications] covers the following functionality: o Ability to subscribe to event notifications using two mechanisms: dynamic and configuration subscriptions. o Ability to subscribe to event notifications using two mechanisms: dynamic and configuration subscriptions. o Ability to negotiate acceptable subscription parameters. Gonzalez Prieto, et al. Expires December 17, 2016 [Page 3] Internet-Draft NETCONF-notifications June 2016 o Ability to filter the subset of notifications to be pushed with stream-specific semantics. o Ability to support multiple encodings for the notification. o Mechanism to communicate the notifications. o Ability to replay locally logged notifications. To support this functionality, NETCONF agents must implement the operations, configuration and operational state defined in [event-notifications]. In addition, they need to: o support multiple subscriptions over a single NETCONF session. o support a revised definition of the default NETCONF stream o be backwards compatible with RFC 5277 implementations. 1.1. 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 RFC 2119 [RFC2119]. 1.1.1. Event Notifications The following terms are defined in [event-notifications]: o Event o Event notification o Stream (also referred to as "event stream") o Subscriber o Receiver o Subscription o Filter o Dynamic subscription o Configured subscription Gonzalez Prieto, et al. Expires December 17, 2016 [Page 4] Internet-Draft NETCONF-notifications June 2016 1.1.2. NETCONF The following terms are defined in [RFC6241] : o Operation o RPC: remote procedure call 1.1.3. NETCONF Access Control The following terms are defined in [RFC6536] : o NACM: NETCONF Access Control Model 1.2. Solution Overview [event-notifications] defines mechanisms that provide an asynchronous message notification delivery service. This document discusses its realization on top of the NETCONF protocol [RFC6241]. The functionality to support is defined in [event-notifications]. It is formalized in a set of yang models. The mapping of yang constructs into NETCONF is described in [RFC6020]. Supporting [event-notifications] requires enhancements and modifications in NETCONF. The key enhacement is suporting multiple subscriptions on a NETCONF session. A key modification is the definition of the NETCONF stream These enhancements do not affect [RFC5277] clients that do not support [event-notifications]. 2. Solution In this section, we describe and exemplify how [event-notifications] must be supported over NETCONF. 2.1. Event Streams In the context of NETCONF, an event stream is a set of events available for subscription from a NETCONF server. It is out of the scope of this document to identify a) how streams are defined, b) how events are defined/generated, and c) how events are assigned to streams. The following is a high-level description of the flow of a notification. Note that it does not mandate and/or preclude an implementation. As events are raised, they are assigned to streams. Gonzalez Prieto, et al. Expires December 17, 2016 [Page 5] Internet-Draft NETCONF-notifications June 2016 An event may be assigned to multiple streams. The event is distributed to subscribers and receivers based on the current subscriptions and access control. Access control is needed because if any receiver of that subscription does not have permission to receive an event, then it never makes it into a notification, and processing of the event is completed for that subscription. 2.2. Event Stream Discovery A NETCONF client can retrieve the list of available event streams from a NETCONF server using the operation. The reply contains the elements defined in the YANG model under the container "/streams", which includes the stream identifier. The following example ilustrates the retrieval of the list of available event streams using the operation. Figure 2: Get streams The NETCONF server returns a list of event streams available for subscription. In this example, the list contains the NETCONF, SNMP, and syslog-critical streams. NETCONF SNMP syslog-critical NETCONF Figure 3: Get streams response Gonzalez Prieto, et al. Expires December 17, 2016 [Page 6] Internet-Draft NETCONF-notifications June 2016 2.2.1. Backwards Compatibility In order to maintain backwards compatibility, clients that only support [RFC5277] can retrieve the list of available event streams executing a operation against the container "/netconf/streams". The following example ilustrates this mechanism. Figure 4: Get streams (backwards compatibility) The NETCONF server returns a list of event streams available for subscription. In this example, the list contains the NETCONF, SNMP, and syslog-critical streams. NETCONF default NETCONF event stream true 2016-02-05T00:00:00Z Gonzalez Prieto, et al. Expires December 17, 2016 [Page 7] Internet-Draft NETCONF-notifications June 2016 SNMP SNMP notifications false syslog-critical Critical and higher severity true 2007-07-01T00:00:00Z Figure 5: Get streams response (backwards compatibility) 2.3. Default Event Stream A NETCONF server implementation supporting the notification capability MUST support the "NETCONF" notification event stream. This stream contains all NETCONF XML event notifications supported by the NETCONF server, except for those belonging only to streams that explicitly indicate that they must be excluded from the NETCONF stream. The exact string "NETCONF" is used during the advertisement of stream support during the operation on and during the and operations. 2.4. Creating a Subscription The following illustrates the creation of a simple subscription. Gonzalez Prieto, et al. Expires December 17, 2016 [Page 8] Internet-Draft NETCONF-notifications June 2016 2.4.1. Usage Example The following demonstrates dynamically creating a subscription. This operation is fully defined in [RFC5277] Figure 6: Create subscription 2.4.2. Positive Response If the NETCONF server can satisfy the request, the server sends an element. Figure 7: Successful create subscription 2.4.3. Negative Response If the request cannot be completed for any reason, an element is included within the . Subscription requests can fail for several reasons including if a filter with invalid syntax is provided or if the name of a non-existent stream is provided. If a stopTime is specified in a request without having specified a startTime, the following error is returned: Gonzalez Prieto, et al. Expires December 17, 2016 [Page 9] Internet-Draft NETCONF-notifications June 2016 Tag: missing-element Error-type: protocol Severity: error Error-info: : startTime Description: An expected element is missing. Figure 8: Create subscription missing an element If the optional replay feature is requested but the NETCONF server does not support it, the following error is returned: Tag: operation-failed Error-type: protocol Severity: error Error-info: none Description: Request could not be completed because the requested operation failed for some reason not covered by any other error condition. Figure 9: Create subscription pperation failed If a stopTime is requested that is earlier than the specified startTime, the following error is returned: Tag: bad-element Error-type: protocol Severity: error Error-info: : stopTime Description: An element value is not correct; e.g., wrong type, out of range, pattern mismatch. Figure 10: Create subscription incorrect stopTime If a startTime is requested that is later than the current time, the following error is returned: Tag: bad-element Error-type: protocol Severity: error Error-info: : startTime Description: An element value is not correct; e.g., wrong type, out of range, pattern mismatch. Figure 11: Create subscription incorrect startTime Gonzalez Prieto, et al. Expires December 17, 2016 [Page 10] Internet-Draft NETCONF-notifications June 2016 2.5. Establishing a Subscription 2.5.1. Usage Example The following illustrates the establishment of a simple subscription. Figure 12: Establish subscription 2.5.2. Positive Response If the NETCONF server can satisfy the request, the server sends a positive element, and the subscription-id of the accepted subscription. ok 52 Figure 13: Successful establish subscription Gonzalez Prieto, et al. Expires December 17, 2016 [Page 11] Internet-Draft NETCONF-notifications June 2016 2.5.3. Negative Response If the NETCONF server cannot satisfy the request, the server sends a negative element. If the client has no authorization to establish the subscription, the indicates an authorization error. For instance: foo error-data-not-authorized Figure 14: Unsuccessful establish subscription If the request is rejected because the server is not able to serve it, the server SHOULD include in the returned error what subscription parameters would have been accepted for the request when it was processed. However, they are no guarantee that subsequent requests with those parameters for this client or others will be accepted. For instance, consider a subscription from [netconf-yang-push], which augments the establish-subscription with some additional parameters, including "period". If the client requests a period the NETCONF server cannot serve, the exchange may be: Gonzalez Prieto, et al. Expires December 17, 2016 [Page 12] Internet-Draft NETCONF-notifications June 2016 push-update 500 encode-xml error-insufficient-resources 2000 Figure 15: Subscription establishment negotiation Subscription requests will fail if a filter with invalid syntax is provided or if the name of a non-existent stream is provided. 2.5.4. Multiple Subscriptions over a Single NETCONF Session Note that [event-notifications] requires supporting multiple subscriptions over a single NETCONF session. In contrast, [RFC5277] mandated server to return an error when a create-subscription was sent while a subscription was active on that session. 2.5.5. Message Flow Examples Gonzalez Prieto, et al. Expires December 17, 2016 [Page 13] Internet-Draft NETCONF-notifications June 2016 +------------+ +-----------+ | Client | | Server | +------------+ +-----------+ | | | Capability Exchange | |<---------------------------->| | | | | | Establish Subscription | |----------------------------->| | RPC Reply: OK, subs-id = 22 | |<-----------------------------| | | | Notification (subs-id 22) | |<-----------------------------| | | | | | Notification (subs-id 22) | |<-----------------------------| | Notification (subs-id 22) | |<-----------------------------| | | | | Figure 16: Message flow for subscription establishment Gonzalez Prieto, et al. Expires December 17, 2016 [Page 14] Internet-Draft NETCONF-notifications June 2016 +------------+ +-----------+ | Client | | Server | +------------+ +-----------+ | | | Capability Exchange | |<---------------------------->| | | | | | Establish Subscription | |----------------------------->| | RPC Reply: OK, subs-id = 22 | |<-----------------------------| | | | Notification (subs-id 22) | |<-----------------------------| | | | | | Establish Subscription | |----------------------------->| | RPC Reply: OK, subs-id = 23 | |<-----------------------------| | | | Notification (subs-id 22) | |<-----------------------------| | | | | | Notification (subs-id 22) | |<-----------------------------| | Notification (subs-id 23) | |<-----------------------------| | | | | Figure 17: Message Flow for multiple subscription establishments over a single session 2.6. Modifying a Subscription 2.6.1. Usage Example The following demonstrates modifying a subscription. Consider a subscription from [netconf-yang-push], which augments the establish- subscription with some additional parameters, including "period". A subscription may be established as follows. Gonzalez Prieto, et al. Expires December 17, 2016 [Page 15] Internet-Draft NETCONF-notifications June 2016 push-update 500 encode-xml ok 1922 Figure 18: Establish subscription to be modified The subscription may be modified with: Gonzalez Prieto, et al. Expires December 17, 2016 [Page 16] Internet-Draft NETCONF-notifications June 2016 1922 1000 ok 1922 Figure 19: Modify subscription 2.6.2. Positive Response If the NETCONF server can satisfy the request, the server sends a positive element. This response is like that to an establish-subscription request. but without the subscription- id, which would be redundant. Gonzalez Prieto, et al. Expires December 17, 2016 [Page 17] Internet-Draft NETCONF-notifications June 2016 1922 1000 ok Figure 20: Successful modify subscription 2.6.3. Negative Response If the NETCONF server cannot satisfy the request, the server sends a negative element. Its contents and semantics are identical to those to an establish-subscription request. For instance: Gonzalez Prieto, et al. Expires December 17, 2016 [Page 18] Internet-Draft NETCONF-notifications June 2016 1922 100 error-insufficient-resources 500 Figure 21: Unsuccessful modify subscription 2.6.4. Message Flow Example Gonzalez Prieto, et al. Expires December 17, 2016 [Page 19] Internet-Draft NETCONF-notifications June 2016 +------------+ +-----------+ | Client | | Server | +------------+ +-----------+ | | | Capability Exchange | |<---------------------------->| | | | | | Establish Subscription | |----------------------------->| | RPC Reply: OK, subs-id = 22 | |<-----------------------------| | | | Notification (subs-id 22) | |<-----------------------------| | | | | | | | | | Modify Subscription | |----------------------------->| | | | | | Notification (subs-id 22) | |<-----------------------------| | Notification (subs-id 22) | |<-----------------------------| | | | | Figure 22: Message flow for subscription modification 2.7. Deleting a Subscription 2.7.1. Usage Example The following demonstrates deleting a subscription. 1922 Figure 23: Delete subscription Gonzalez Prieto, et al. Expires December 17, 2016 [Page 20] Internet-Draft NETCONF-notifications June 2016 2.7.2. Positive Response If the NETCONF server can satisfy the request, the server sends an OK element. For example: 1922 Figure 24: Successful delete subscription 2.7.3. Negative Response If the NETCONF server cannot satisfy the request, the server sends an error-rpc element. For example: Gonzalez Prieto, et al. Expires December 17, 2016 [Page 21] Internet-Draft NETCONF-notifications June 2016 2017 application invalid-value error /t:subscription-id Subscription-id 2017 does not exist Figure 25: Unsuccessful delete subscription 2.7.4. Message Flow Example Gonzalez Prieto, et al. Expires December 17, 2016 [Page 22] Internet-Draft NETCONF-notifications June 2016 +------------+ +-----------+ | Client | | Server | +------------+ +-----------+ | | | Capability Exchange | |<---------------------------->| | | | | | Establish Subscription | |----------------------------->| | RPC Reply: OK, subs-id = 22 | |<-----------------------------| | | | Notification (subs-id 22) | |<-----------------------------| | | | | | Notification (subs-id 22) | |<-----------------------------| | Notification (subs-id 22) | |<-----------------------------| | | | | | Delete Subscription | |----------------------------->| | | | | | | | | Figure 26: Message flow for subscription deletion 2.8. Configured Subscriptions A configured subscription is a subscription installed via a configuration interface, and do not support negotiation. Supporting configured subscriptions is optional and advertised during the capabilities exchange using the "configured-subscriptions" feature. In this section, we present examples of how to manage configuration subscriptions using a NETCONF client. Gonzalez Prieto, et al. Expires December 17, 2016 [Page 23] Internet-Draft NETCONF-notifications June 2016 2.8.1. Establishing a Configured Subscription Subscriptions are established using configuration operations against the top-level subtree subscription-config. For example at subscription establishment, a NETCONF client may send: 1922 foo
1.2.3.4
1234 Figure 27: Establish static subscription if the request is accepted, the server would reply: Figure 28: Response to a successful static subscription establishment Gonzalez Prieto, et al. Expires December 17, 2016 [Page 24] Internet-Draft NETCONF-notifications June 2016 if the request is not accepted because the server cannot serve it, the server may reply: application resource-denied error Temporarily the server cannot serve this subscription due to the current workload. Figure 29: Response to a failed static subscription establishment 2.8.1.1. Message Flow Example Gonzalez Prieto, et al. Expires December 17, 2016 [Page 25] Internet-Draft NETCONF-notifications June 2016 +----------+ +-----------+ +---------+ +---------+ | Client | | Server | | Rcver A | | Rcver B | +----------+ +-----------+ +---------+ +---------+ | | | | | Capability Exchange | | | |<-------------------------->| | | | | | | | | | | | Edit-config | | | |--------------------------->| | | | RPC Reply: OK | | | |<---------------------------| | | | | Subscription | | | | Started | | | | (subs-id 22) | | | |--------------->| | | |---------------------------->| | | | | | | Notification | | | | (subs-id 22) | | | |--------------->| | | |---------------------------->| | | | | | | | | | | | | | | | | | | | | | | Notification | | | | (subs-id 22) | | | |--------------->| | | |---------------------------->| | | | | | | Notification | | | | (subs-id 22) | | | |--------------->| | | |---------------------------->| | | | | Figure 30: Message flow for subscription establishment (configured subscription) 2.8.2. Modifying a Configured Subscription Configured subscriptions can be modified using configuration operations against the top-level subtree subscription-config. Gonzalez Prieto, et al. Expires December 17, 2016 [Page 26] Internet-Draft NETCONF-notifications June 2016 For example, the subscription established in the previous section could be modified as follows, choosing a different receiver: 1922 foo
1.2.3.5
1234 Figure 31: Modify configured subscription if the request is accepted, the server would reply: Figure 32: Response to a successful configured subscription modification Gonzalez Prieto, et al. Expires December 17, 2016 [Page 27] Internet-Draft NETCONF-notifications June 2016 2.8.2.1. Message Flow Example Gonzalez Prieto, et al. Expires December 17, 2016 [Page 28] Internet-Draft NETCONF-notifications June 2016 +----------+ +-----------+ +---------+ +---------+ | Client | | Server | | Rcver A | | Rcver B | +----------+ +-----------+ +---------+ +---------+ | | | | | Capability Exchange | | | |<-------------------------->| | | | | | | | | | | | Edit-config | | | |--------------------------->| | | | RPC Reply: OK | | | |<---------------------------| | | | | Subscription | | | | Started | | | | (subs-id 22) | | | |--------------->| | | |---------------------------->| | | | | | | Notification | | | | (subs-id 22) | | | |--------------->| | | |---------------------------->| | | | | | | | | | | | | | Edit-config | | | |--------------------------->| | | | RPC Reply: OK | | | |<---------------------------| | | | | | | | | | | | | Subscription | | | | Modified | | | | (subs-id 22) | | | |--------------->| | | |---------------------------->| | | | | | | Notification | | | | (subs-id 22) | | | |--------------->| | | |---------------------------->| | | | | Figure 33: Message flow for subscription modification (configured subscription) Gonzalez Prieto, et al. Expires December 17, 2016 [Page 29] Internet-Draft NETCONF-notifications June 2016 2.8.3. Deleting a Configured Subscription Subscriptions can be deleted using configuration operations against the top-level subtree subscription-config. For example: 1922 Figure 34: Deleting a configured subscription 2.8.3.1. Message Flow Example +----------+ +-----------+ +---------+ +---------+ | Client | | Server | | Rcver A | | Rcver B | +----------+ +-----------+ +---------+ +---------+ | | | | | Capability Exchange | | | |<-------------------------->| | | | | | | | | | | | Edit-config | | | |--------------------------->| | | | RPC Reply: OK | | | |<---------------------------| | | | | Subscription | | | | Started | | | | (subs-id 22) | | Gonzalez Prieto, et al. Expires December 17, 2016 [Page 30] Internet-Draft NETCONF-notifications June 2016 | |--------------->| | | |---------------------------->| | | | | | | Notification | | | | (subs-id 22) | | | |--------------->| | | |---------------------------->| | | | | | | | | | | | | | | | | | | | | | | Notification | | | | (subs-id 22) | | | |--------------->| | | |---------------------------->| | | | | | Edit-config | | | |--------------------------->| | | | RPC Reply: OK | | | |<---------------------------| | | | | | | | | | | | | Subscription | | | | Terminated | | | | (subs-id 22) | | | |--------------->| | | |---------------------------->| | | | | | | | | | | | | | | | | Figure 35: Message flow for subscription deletion (configured subscription) 2.9. Event (Data Plane) Notifications Once a subscription has been set up, the NETCONF server sends (asynchronously) the event notifications from the subscribed stream. We refer to these as data plane notifications. For dynamic subscriptions set up via RPC operations, event notifications are sent over the NETCONF session used to create or establish the subscription. For static subscriptions, event notifications are sent over the specified connections. Gonzalez Prieto, et al. Expires December 17, 2016 [Page 31] Internet-Draft NETCONF-notifications June 2016 An event notification is sent to the receiver(s) when an event of interest (i.e., meeting the specified filtering criteria) has occurred. An event notification is a complete and well-formed XML document. Note that is not a Remote Procedure Call (RPC) method but rather the top-level element identifying the one-way message as a notification. Note that event notifications never trigger responses. The event notification always includes an element. It is the time the event was generated by the event source. This parameter is of type dateTime and compliant to [RFC3339]. Implementations must support time zones. The event notification also contains notification-specific tagged content, if any. With the exception of , the content of the notification is beyond the scope of this document. For the encodings other than XML, notifications include an additional XML element so that the notification is a well-formed XML. The element is , E.g., . That element contains the notification contents in the desired encoding The following is an example of an event notification from [RFC6020]: notification link-failure { description "A link failure has been detected"; leaf if-name { type leafref { path "/interface/name"; } } leaf if-admin-status { type admin-status; } leaf if-oper-status { type oper-status; } } Figure 36: Definition of a data plane notification Gonzalez Prieto, et al. Expires December 17, 2016 [Page 32] Internet-Draft NETCONF-notifications June 2016 2007-09-01T10:00:00Z so-1/2/3.0 up down Figure 37: Data plane notification The equivalent using JSON encoding would be 2007-09-01T10:00:00Z { "acme-system:link-failure": { "if-name": "so-1/2/3.0", "if-admin-status": "up", "if-oper-status": "down " } } Figure 38: Data plane notification using JSON encoding 2.10. Control Plane Notifications In addition to data plane notifications, a server may send control plane notifications (defined in [event-notifications]) to indicate to receivers that an event related to the subscription management has occurred. Control plane notifications cannot be filtered out. Next we exemplify them using both XML, and JSON encondings for the data: 2.10.1. replayComplete 2007-09-01T10:00:00Z Figure 39: replayComplete control plane notification Gonzalez Prieto, et al. Expires December 17, 2016 [Page 33] Internet-Draft NETCONF-notifications June 2016 The equivalent using JSON encoding would be: 2007-09-01T10:00:00Z { "netmod-notif:replayComplete": { } } Figure 40: replayComplete control plane notification (JSON encoding) 2.10.1.1. Message Flow Example Gonzalez Prieto, et al. Expires December 17, 2016 [Page 34] Internet-Draft NETCONF-notifications June 2016 +------------+ +-----------+ | Client | | Server | +------------+ +-----------+ | | | Capability Exchange | |<---------------------------->| | | | | | Establish Subscription | |----------------------------->| | RPC Reply: OK, subs-id = 22 | |<-----------------------------| | | | Notification (subs-id 22) | |<-----------------------------| | | | | | Notification (subs-id 22) | |<-----------------------------| | Replay Complete (subs-id 22) | |<-----------------------------| | | | | | | | Notification (subs-id 22) | |<-----------------------------| | | | Notification (subs-id 22) | |<-----------------------------| | | | | | | Figure 41: replayComplete notification 2.10.2. notificationComplete 2007-09-01T10:00:00Z Figure 42: notificationComplete control plane notification Gonzalez Prieto, et al. Expires December 17, 2016 [Page 35] Internet-Draft NETCONF-notifications June 2016 2.10.2.1. Message Flow Example Gonzalez Prieto, et al. Expires December 17, 2016 [Page 36] Internet-Draft NETCONF-notifications June 2016 +------------+ +-----------+ | Client | | Server | +------------+ +-----------+ | | | Capability Exchange | |<---------------------------->| | | | | | Establish Subscription | |----------------------------->| | RPC Reply: OK, subs-id = 22 | |<-----------------------------| | | | Notification (subs-id 22) | |<-----------------------------| | | | | | Notification (subs-id 22) | |<-----------------------------| | Replay Complete (subs-id 22) | |<-----------------------------| | | | | | | | Notification (subs-id 22) | |<-----------------------------| | | | Notification (subs-id 22) | |<-----------------------------| | | | | | | | Notification Complete | | (subs-id 22) | |<-----------------------------| | | | | | | | RPC | |----------------------------->| | RPC Reply | |<-----------------------------| | | | | Figure 43: notificationComplete notification Gonzalez Prieto, et al. Expires December 17, 2016 [Page 37] Internet-Draft NETCONF-notifications June 2016 2.10.3. subscription-started 2007-09-01T10:00:00Z 52 Figure 44: subscription-started control plane notification The equivalent using JSON encoding would be: 2007-09-01T10:00:00Z { "notif-bis:subscription-started": { "subscription-id" : 52 ((Open Item: express filter in json)) } } Figure 45: subscription-started control plane notification (JSON encoding) 2.10.4. subscription-modified Gonzalez Prieto, et al. Expires December 17, 2016 [Page 38] Internet-Draft NETCONF-notifications June 2016 2007-09-01T10:00:00Z 52 Figure 46: subscription-modified control plane notification 2.10.5. subscription-terminated 2007-09-01T10:00:00Z 52 subscription-deleted Figure 47: subscription-terminated control plane notification 2.10.6. subscription-suspended 2007-09-01T10:00:00Z 52 internal-error Figure 48: subscription-suspended control plane notification 2.10.7. subscription-resumed Gonzalez Prieto, et al. Expires December 17, 2016 [Page 39] Internet-Draft NETCONF-notifications June 2016 2007-09-01T10:00:00Z 52 internal-error Figure 49: subscription-resumed control plane notification 2.10.7.1. Message Flow Examples Gonzalez Prieto, et al. Expires December 17, 2016 [Page 40] Internet-Draft NETCONF-notifications June 2016 +------------+ +-----------+ | Client | | Server | +------------+ +-----------+ | | | Capability Exchange | |<---------------------------->| | | | | | Establish Subscription | |----------------------------->| | RPC Reply: OK, subs-id = 22 | |<-----------------------------| | | | Notification | |<-----------------------------| | | | | | Notification | |<-----------------------------| | Notification | |<-----------------------------| | | | | | Subscription Suspended | |<-----------------------------| | | | | | | | Subscription Resumed | |<-----------------------------| | | | | | | | | | Notification | |<-----------------------------| | | | | Figure 50: subscription-suspended and Resumed Notifications +----------+ +-----------+ +---------+ +---------+ | Client | | Server | | Rcver A | | Rcver B | +----------+ +-----------+ +---------+ +---------+ | | | | | Capability Exchange | | | Gonzalez Prieto, et al. Expires December 17, 2016 [Page 41] Internet-Draft NETCONF-notifications June 2016 |<-------------------------->| | | | | | | | | | | | Edit-config | | | |--------------------------->| | | | RPC Reply: OK | | | |<---------------------------| | | | | Subscription | | | | Started | | | |--------------->| | | |---------------------------->| | | | | | | Notification | | | |--------------->| | | |---------------------------->| | | | | | | | | | | | | | | | | | | Subscription | | | | Suspended | | | |--------------->| | | |---------------------------->| | | | | | | | | | | | | | | | | | | | | | | Subscription | | | | Resumed | | | |--------------->| | | |---------------------------->| | | | | | | | | | | | | | | Notification | | | |--------------->| | | |---------------------------->| | | | | | | Notification | | | |--------------->| | | |---------------------------->| | | | | | | | | | | | | | | | | Gonzalez Prieto, et al. Expires December 17, 2016 [Page 42] Internet-Draft NETCONF-notifications June 2016 Figure 51: subscription-suspended and subscription-resumed notifications (configured subscriptions) 3. Backwards Compatibility 3.1. Capabilities Capabilities are advertised in messages sent by each peer during session establishment [RFC6241]. Servers supporting the features in this document must advertise both capabilities "urn:ietf:params:netconf:capability:notification:1.0" and "urn:ietf:params:netconf:capability:notification:1.1". An example of a hello message by a server during session establishment would be: urn:ietf:params:xml:ns:netconf:base:1.0 urn:ietf:params:netconf:capability:startup:1.0 urn:ietf:params:netconf:capability:notification:1.0 urn:ietf:params:netconf:capability:notification:1.1 4 Figure 52: Hello message Clients that only support [RFC5277] recognize capability "urn:ietf:params:netconf:capability:notification:1.0" and ignore capability "urn:ietf:params:netconf:capability:notification:1.1". This allows them interacting with the server as per [RFC5277]. Clients that support the features in this document recognize both capabilities. This allows them interacting with the server as per this document. Gonzalez Prieto, et al. Expires December 17, 2016 [Page 43] Internet-Draft NETCONF-notifications June 2016 3.2. Stream Discovery In order to maintain backwards compatibility, clients that only support [RFC5277] can retrieve the list of available event streams executing a operation against the container "/netconf/streams". 4. Security Considerations The security considerations from the base NETCONF document [RFC6241] also apply to the notification capability. The elements are never sent before the transport layer and the NETCONF layer, including capabilities exchange, have been established and the manager has been identified and authenticated. A secure transport must be used and the server must ensure that the user has sufficient authorization to perform the function they are requesting against the specific subset of NETCONF content involved. When a is received that refers to the content defined in this memo, clients should only be able to view the content for which they have sufficient privileges. and operations can be considered like deferred , and the content that different users can access may vary. This different access is reflected in the that different users are able to subscribe to. The contents of notifications, as well as the names of event streams, may contain sensitive information and care should be taken to ensure that they are viewed only by authorized users. The NETCONF server MUST NOT include any content in a notification that the user is not authorized to view. If a malicious or buggy NETCONF client sends a number of requests, then these subscriptions accumulate and may use up system resources. In such a situation, subscriptions can be terminated by terminating the suspect underlying NETCONF sessions using the operation. If the client uses , the server can also suspend or terminate subscriptions with per-subscription granularity. A subscription could be configured on another receiver's behalf, with the goal of flooding that receiver with updates. One or more publishers could be used to overwhelm a receiver, which doesn't even support subscriptions. Clients that do not want pushed data need only terminate or refuse any transport sessions from the publisher. In addition, the NETCONF Authorization Control Model [RFC6536] SHOULD be used to control and restrict authorization of subscription configuration. This control models permits specifying per-user Gonzalez Prieto, et al. Expires December 17, 2016 [Page 44] Internet-Draft NETCONF-notifications June 2016 permissions to receive specific event notification types. The permissions are specified as a set of access control rules. Note that streams can define additional authorization requirements. For instance, in [netconf-yang-push] each of the elements in its data plane notifications must also go through access control. 5. Acknowledgments We wish to acknowledge the helpful contributions, comments, and suggestions that were received from: Andy Bierman, Yan Gang, Peipei Guo, Susan Hares, Tim Jenkins, Balazs Lengyel, Kent Watsen, and Guangying Zheng. 6. References 6.1. 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, . [RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet: Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002, . [RFC5277] Chisholm, S. and H. Trevino, "NETCONF Event Notifications", RFC 5277, DOI 10.17487/RFC5277, July 2008, . [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, . [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration Protocol (NETCONF) Access Control Model", RFC 6536, DOI 10.17487/RFC6536, March 2012, . Gonzalez Prieto, et al. Expires December 17, 2016 [Page 45] Internet-Draft NETCONF-notifications June 2016 6.2. Informative References [event-notifications] Gonzalez Prieto, A., Clemm, A., Voit, Eric., Nilsen- Nygaard, E., Tripathy, A., Chisholm, S., and H. Trevino, "Subscribing to YANG-Defined Event Notifications", June 2016, . [netconf-yang-push] Clemm, A., Gonzalez Prieto, A., Voit, Eric., Tripathy, A., and E. Nilsen-Nygaard, "Subscribing to YANG datastore push updates", February 2016, . Appendix A. Issues being worked and resolved (To be removed by RFC editor prior to publication) A.1. Unresolved Issues NT1 - Support multiple create-subscriptions over a single NETCONF session? or only multiple establish-subscription? Recommend only establish-subscription anytime there may be more than one subscription, otherwise variations of supported RFCs and error states proliferate. NT2 - Configured subscription need to be refined in [event-notifications] and then adjust this document based on it. NT3 - Express filter in JSON should be documented. A.2. Agreement in principal NT1 - When a list of requirements for secure transport is provided via a Configured Subscription, this list must be met via Netconf transport. Specifics still are needed for draft on the "how". NT2 - Along with rfc5277bis, this draft to obsolete 5277 NT3 - Stream discovery. Adopted mechanism in 5277-bis and include backwards comptability support. Gonzalez Prieto, et al. Expires December 17, 2016 [Page 46] Internet-Draft NETCONF-notifications June 2016 Authors' Addresses Alberto Gonzalez Prieto Cisco Systems Email: albertgo@cisco.com Alexander Clemm Cisco Systems Email: alex@cisco.com Eric Voit Cisco Systems Email: evoit@cisco.com Einar Nilsen-Nygaard Cisco Systems Email: einarnn@cisco.com Ambika Prasad Tripathy Cisco Systems Email: ambtripa@cisco.com Sharon Chisholm Ciena Email: schishol@ciena.com Hector Trevino Cisco Systems Email: htrevino@cisco.com Gonzalez Prieto, et al. Expires December 17, 2016 [Page 47]