Network Working Group S. Chisholm Internet-Draft K. Curran Expires: July 12, 2006 Nortel H. Trevino Cisco January 8, 2006 NETCONF Event Notifications draft-ietf-netconf-notification-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on July 12, 2006. Copyright Notice Copyright (C) The Internet Society (2006). Abstract This memo defines a framework for sending asynchronous messages, or event notifications in NETCONF. It defines both the operations necessary to support this concept, and also discusses implications for the mapping to application protocols. Chisholm, et al. Expires July 12, 2006 [Page 1] Internet-Draft NETCONF Event Notifications January 2006 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1 Definition of Terms . . . . . . . . . . . . . . . . . . . 4 1.2 Event Notifications in NETCONF . . . . . . . . . . . . . . 5 2. Event-Related Operations . . . . . . . . . . . . . . . . . . . 6 2.1 Subscribing to receive Events . . . . . . . . . . . . . . 6 2.1.1 create-subscription . . . . . . . . . . . . . . . . . 6 2.2 Sending Event Notifications . . . . . . . . . . . . . . . 7 2.2.1 Events . . . . . . . . . . . . . . . . . . . . . . . . 7 2.3 Changing the Subscription . . . . . . . . . . . . . . . . 8 2.3.1 modify-subscription . . . . . . . . . . . . . . . . . 9 2.4 Terminating the Subscription . . . . . . . . . . . . . . . 10 2.4.1 cancel-subscription . . . . . . . . . . . . . . . . . 10 3. Supporting Concepts . . . . . . . . . . . . . . . . . . . . . 11 3.1 Capabilities Exchange . . . . . . . . . . . . . . . . . . 11 3.2 Querying Subscription Properties . . . . . . . . . . . . . 11 3.3 RPC One-way Messages . . . . . . . . . . . . . . . . . . . 14 3.4 User-Specified Filters . . . . . . . . . . . . . . . . . . 14 3.4.1 Named Profiles . . . . . . . . . . . . . . . . . . . . 15 3.4.2 Filtering . . . . . . . . . . . . . . . . . . . . . . 15 3.5 Event Classes . . . . . . . . . . . . . . . . . . . . . . 15 3.6 Defining Event Notifications . . . . . . . . . . . . . . . 16 3.7 Interleaving Messages . . . . . . . . . . . . . . . . . . 16 4. XML Schema for Event Notifications . . . . . . . . . . . . . . 18 5. Mapping to Application Protocols . . . . . . . . . . . . . . . 23 5.1 SSH . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 5.2 BEEP . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 5.2.1 One-way Messages in Beep . . . . . . . . . . . . . . . 24 5.3 SOAP . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 5.3.1 A NETCONF over Soap over HTTP Example . . . . . . . . 25 6. Filtering examples . . . . . . . . . . . . . . . . . . . . . . 28 6.1 Event Classes . . . . . . . . . . . . . . . . . . . . . . 28 6.2 Subtree Filtering . . . . . . . . . . . . . . . . . . . . 28 6.3 XPATH filters . . . . . . . . . . . . . . . . . . . . . . 30 7. Security Considerations . . . . . . . . . . . . . . . . . . . 32 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 33 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 34 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 34 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 35 A. Potential Event Content . . . . . . . . . . . . . . . . . . . 36 A.1 Event Identifier . . . . . . . . . . . . . . . . . . . . . 36 A.2 Resource Instance . . . . . . . . . . . . . . . . . . . . 36 A.3 Event Time . . . . . . . . . . . . . . . . . . . . . . . . 36 A.4 Perceived Severity . . . . . . . . . . . . . . . . . . . . 36 A.5 Probable Cause . . . . . . . . . . . . . . . . . . . . . . 37 A.6 Specific Problem . . . . . . . . . . . . . . . . . . . . . 37 A.7 Trend Indication . . . . . . . . . . . . . . . . . . . . . 37 Chisholm, et al. Expires July 12, 2006 [Page 2] Internet-Draft NETCONF Event Notifications January 2006 A.8 Additional Alarm Text . . . . . . . . . . . . . . . . . . 37 A.9 Threshold Identifier . . . . . . . . . . . . . . . . . . . 37 A.10 Threshold Type . . . . . . . . . . . . . . . . . . . . . . 38 A.11 Observed Value . . . . . . . . . . . . . . . . . . . . . . 38 A.12 State Change Information . . . . . . . . . . . . . . . . . 38 B. Configuration Event Class Notifications . . . . . . . . . . . 39 B.1 Types of Configuration Events . . . . . . . . . . . . . . 39 B.2 Config Event Notification Structure . . . . . . . . . . . 40 B.3 Configuration Event Content . . . . . . . . . . . . . . . 42 B.3.1 Target Datastore . . . . . . . . . . . . . . . . . . . 42 B.3.2 User Info . . . . . . . . . . . . . . . . . . . . . . 42 B.3.3 Data Source . . . . . . . . . . . . . . . . . . . . . 42 B.3.4 Operation . . . . . . . . . . . . . . . . . . . . . . 42 B.3.5 Context . . . . . . . . . . . . . . . . . . . . . . . 42 B.3.6 Entered Command . . . . . . . . . . . . . . . . . . . 43 B.3.7 New Config . . . . . . . . . . . . . . . . . . . . . . 43 B.3.8 Old Config . . . . . . . . . . . . . . . . . . . . . . 43 B.3.9 Non-netconf commands in configuration notifications . 43 B.4 Design Alternative . . . . . . . . . . . . . . . . . . . . 43 B.4.1 Server Session Initiation . . . . . . . . . . . . . . 43 B.4.2 Establishment . . . . . . . . . . . . . . . . . . . . 44 B.4.3 Teardown . . . . . . . . . . . . . . . . . . . . . . . 44 B.4.4 Suspend And Resume . . . . . . . . . . . . . . . . . . 45 B.4.5 Lifecycle . . . . . . . . . . . . . . . . . . . . . . 45 C. NETCONF Event Notifications and Syslog . . . . . . . . . . . . 46 C.1 Leveraging Syslog Field Definitions . . . . . . . . . . . 46 C.1.1 Field Mapping . . . . . . . . . . . . . . . . . . . . 47 C.1.2 Severity Mapping . . . . . . . . . . . . . . . . . . . 48 C.2 Syslog within NETCONF Events . . . . . . . . . . . . . . . 48 C.2.1 Motivation . . . . . . . . . . . . . . . . . . . . . . 48 C.2.2 Embedding syslog messages in a NETCONF Event . . . . . 48 C.2.3 Supported Forwarding Options . . . . . . . . . . . . . 49 Intellectual Property and Copyright Statements . . . . . . . . 51 Chisholm, et al. Expires July 12, 2006 [Page 3] Internet-Draft NETCONF Event Notifications January 2006 1. Introduction NETCONF [NETCONF-PROTO] can be conceptually partitioned into four layers: Layer Example +-------------+ +-----------------------------+ | Content | | Configuration data | +-------------+ +-----------------------------+ | | +-------------+ +-----------------------------+ | Operations | | , | +-------------+ +-----------------------------+ | | +-------------+ +-----------------------------+ | RPC | | , | +-------------+ +-----------------------------+ | | +-------------+ +-----------------------------+ | Application | | BEEP, SSH, SSL, console | | Protocol | | | +-------------+ +-----------------------------+ This document defines a framework for sending asynchronous messages, or event notifications in NETCONF. It defines both the operations necessary to support this concept, and also discusses implications for the mapping to application protocols. Figure 1 1.1 Definition of Terms 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 [3]. Element: An XML Element[XML]. Managed Entity: A node, which supports NETCONF[NETCONF] and has access to management instrumentation. This is also known as the NETCONF server. Managed Object: A collection of one of more Elements that define an abstract thing of interest. Chisholm, et al. Expires July 12, 2006 [Page 4] Internet-Draft NETCONF Event Notifications January 2006 1.2 Event Notifications in NETCONF An event is something that happens which may be of interest - a configuration change, a fault, a change in status, crossing a threshold, or an external input to the system, for example. Often this results in an asynchronous message, sometimes referred to as a notification or event notification, being sent out to interested parties to notify them that this event has occurred. This memo defines a mechanism whereby the NETCONF client indicates interest in receiving event notifications from a NETCONF server by creating a subscription to receive event notifications. The NETCONF server replies to indicate whether the subscription request was successful and, if it was successful, begins sending the event notifications to the NETCONF client as the events occur within the system. These event notifications will continue to be sent until either the NETCONF session is terminated or an explicit command to cancel the subscription is sent. The event notification subscription allows a number of options to enable the NETCONF client to specify which events are of interest. These are specified when the subscription is created, but can be modified later using a modify subscription command. Chisholm, et al. Expires July 12, 2006 [Page 5] Internet-Draft NETCONF Event Notifications January 2006 2. Event-Related Operations 2.1 Subscribing to receive Events The event notification subscription is initiated by the NETCONF client and responded to by the NETCONF server. When the event notification subscription is created, the events of interest are specified. It is possible to create more than one event notification subscription on a single underlying connection. Each event notification subscription therefore has its own unique identifier. Content for an event notification subscription can be selected by specifying which event classes are of interest and /or by applying user-specified filters. 2.1.1 create-subscription Description: This command initiates an event notification subscription which will send asynchronous event notifications to the initiator of the command until the command is sent. Parameters: Event Classes: An optional parameter that indicates which event classes are of interest. If not present, events of all classes will be sent. Filter: An optional parameter that indicates which subset of all possible events are of interest. The format of this parameter is the same as that of the filter parameter in the NETCONF protocol operations. If not present, all events not precluded by other parameters will be sent. These filter parameters can only be modified using the modify-subscription command. Named Profile Chisholm, et al. Expires July 12, 2006 [Page 6] Internet-Draft NETCONF Event Notifications January 2006 An optional parameter that points to a separately defined filter profile. If not present, no additional filtering will be applied. If the separate definition of these filters is updated, then these changes will be reflected in the filtered events on this subscription. Positive Response: If the NETCONF server can satisfy the request, the server sends an element containing a element containing the subscription ID. Negative Response: An element is included within the if the request cannot be completed for any reason. 2.2 Sending Event Notifications Once the subscription has been set up, the NETCONF server sends the event notifications asynchronously along the connection. Notifications are tagged with event classes, subscription ID, sequence number, and date and time. 2.2.1 Events Events Description: An event notification is sent to the initiator of an command asynchronously when an event of interest to them has occurred. An event notification is a complete XML document. Parameters: Event Classes: The event class or classes associated with this event notification Chisholm, et al. Expires July 12, 2006 [Page 7] Internet-Draft NETCONF Event Notifications January 2006 Subscription Id: A unique identifier for this event subscription Sequence Number: A sequentially increasing number to uniquely identify event notifications for this subscription. It starts at 0, always increases by just one and rolls back to 0 after its maximum value is reached. Date and Time: The date and time that the event notification was sent by the NETCONF server. Positive Response: No response. Negative Response: No response. 2.2.1.1 Event Notification The NETCONF Event notification structure is shown in the following figure. _____________ |RPC-Header|| |__________|| |message-id|| |__________|| ____________________________________________________________________ || Event Header || Data | ||__________________________________________________________||______| || subscriptionId| eventClasses| sequenceNumber| dataAndTime|| | ||_______________|_____________|_______________|____________||______| 2.3 Changing the Subscription After an event notification subscription has been established, the NETCONF client can initiate a request to change properties of the event notification subscription. This prevents loss of event notifications that might otherwise occur during a tear down and Chisholm, et al. Expires July 12, 2006 [Page 8] Internet-Draft NETCONF Event Notifications January 2006 recreation of the event notification subscription. This command is responded to by the NETCONF server 2.3.1 modify-subscription Description: Change properties of the event notification subscription. Parameters: Subscription Id: A unique identifier for this event subscription. Event Classes: An optional parameter that indicates which Event Classes are of interest. If not present, events of all classes will be sent. Filter: An optional parameter that indicates which subset of all possible events that are of interest. The format is the same filter used for other NETCONF commands. If not present, all events not precluded by other parameters will be sent. These filter parameters can only be modified using the modify- subscription command. Named Profile: An optional parameter that points to separately defined filter profile. If not present, no additional filtering will be applied. If the separate definition of these filters is updated, then these changes will be reflected in the events seen on this subscription. Positive Response: If the NETCONF server was able to satisfy the request, an is sent that includes an element. Negative Response: Chisholm, et al. Expires July 12, 2006 [Page 9] Internet-Draft NETCONF Event Notifications January 2006 An element is included within the if the request cannot be completed for any reason. 2.4 Terminating the Subscription Closing of the event notification subscription is initiated by the NETCONF client. The specific subscription to be closed is specified using a subscription ID. The NETCONF server responds. Note that the NETCONF session may also be torn down for other reasons and this will also result in the subscription being cancelled, but is not subjected to the behaviour of this command. 2.4.1 cancel-subscription Description: Tear down the event notification subscription. Parameters: Subscription Id: A unique identifier for this event notification subscription. Positive Response: If the NETCONF server was able to satisfy the request, an is sent that includes an element. Negative Response: An element is included within the if the request cannot be completed for any reason. Chisholm, et al. Expires July 12, 2006 [Page 10] Internet-Draft NETCONF Event Notifications January 2006 3. Supporting Concepts 3.1 Capabilities Exchange The ability to process and send event notifications is advertised during the capability exchange between the NETCONF client and server. "urn:ietf:params:xml:ns:netconf:notification:1.0" For Example urn:ietf:params:xml:ns:netconf:base:1.0 urn:ietf:params:xml:ns:netconf:capability:startup:1.0 urn:ietf:params:xml:ns:netconf:notification:1.0 4 3.2 Querying Subscription Properties The following Schema can be used to retrieve information about active event notification subscriptions Chisholm, et al. Expires July 12, 2006 [Page 11] Internet-Draft NETCONF Event Notifications January 2006 Schema for reporting on Event Subscriptions NetConf State Schema 2005-11-30T09:30:47-05:00 IETF A schema that can be used to learn about current NetConf Event Subscriptions The session id associated with this subscription. The subscription id associated with this subscription. Chisholm, et al. Expires July 12, 2006 [Page 12] Internet-Draft NETCONF Event Notifications January 2006 The event classes associated with this subscription. The filters associated with this subscription. The named profile associated with this subscription. Note that the contents of the named profile may have changed since it was last applied The last time this subscription was modified. If it has not been modified since creation, this is the time of subscription creation. Chisholm, et al. Expires July 12, 2006 [Page 13] Internet-Draft NETCONF Event Notifications January 2006 A count of event notifications sent along this connection since the subscription was created. The sequence number of the last event notification sent to this subscription 3.3 RPC One-way Messages In order to support the concept that each individual event notification is a well-defined XML-document that can be processed without waiting for all events to come in, it makes sense to define events, not as an endless reply to a subscription command, but as independent messages that originate from the NETCONF server. In order to support this model, this memo introduces the concept of a one-way RPC message. The one-way RPC message is similar to the two-way RPC message, except that no response is expected to the command. In the case of event notification, this RPC will originate from the NETCONF server, and not the NETCONF client. 3.4 User-Specified Filters Note that when multiple filters are specified, they are applied Chisholm, et al. Expires July 12, 2006 [Page 14] Internet-Draft NETCONF Event Notifications January 2006 collectively, so event notifications needs to pass all specified filters in order to be sent to the subscriber. If a filter is specified to look for data of a particular value, and the data item is not present within a particular event for its value to be checked, it will be filtered out. For example, if one were to check for 'severity=critical' in a configuration event notification where this field was not supported, then the notification would be filtered out. 3.4.1 Named Profiles A named profile is a filter that is created ahead of time and applied at the time an event notification subscription is created or modified. Note that changes to the profile after the subscription has been created will have no effect unless a modify subscription command is issued. Since named profiles exist outside of the subscription, they persist after the subscription has been cancelled. 3.4.2 Filtering Just-in-time filtering is explicitly stated when the event notification subscription is created. It can only be changed using the modify subscription command. This is specified via the Filter parameter. Filters only exist as parameters to the subscription. 3.5 Event Classes Events can be broadly classified into one more event classes. Each event class identifies a set of event notifications which share important characteristics, such being generated from similar events or sharing much of the same content. The initial set of event classes is fault, configuration, state, audit, data, maintenance, metrics, security, information and heartbeat. A fault event notification is generated when a fault condition (error or warning) occurs. A fault event may result in an alarm. Examples of fault events could be a communications alarm, environmental alarm, equipment alarm, processing error alarm, quality of service alarm, or a threshold crossing event. See RFC3877 and RFC2819 for more information. A configuration event, alternatively known as an inventory event, is used to notify that hardware, software, or a service has been added/ changed/removed. In keeping aligned with NETCONF protocol operations, configuration events may included copy configuration event, delete configuration event, or the edit configuration event (create, delete, merge, replace). Chisholm, et al. Expires July 12, 2006 [Page 15] Internet-Draft NETCONF Event Notifications January 2006 A state event indicates a change from one state to another, where a state is a condition or stage in the existence of a managed entity. State change events are seen in many specifications. For Entity state changes, see [Entity-State-MIB] for more information. Audit events provide event of very specific actions within a managed device. In isolation an audit events provides very limited data. A collection of audit information forms an audit trail. A data dump event is an asynchronous event containing information about a system, its configuration, state, etc. A maintenance event signals the beginning, process or end of an action either generated by a manual or automated maintenance action. A metrics event contains a metric or a collection of metrics. This includes performance metrics. A heart beat event is sent periodically to enable testing that the communications channel is still functional. It behaves much like the other event classes, with the exception that implementations may not want to include an event log, if supported. Although widely used throughout the industry, no current corresponding work within the IETF. However, other standards bodies such as the TeleManagement Forum have similar definitions. An Information event is something that happens of interest which is within the expected operational behaviour and not otherwise covered by another class. 3.6 Defining Event Notifications Event Notifications are defined ahead of time by defining an XML element and assigning it to particular event classes. This will be done using an "eventClasses" attribute. 3.7 Interleaving Messages While each NETCONF message must be a complete XML document, the design of the event system allows for the interleaving of complete asynchronous event notifications with complete synchronous messages. It is possible to still send command-response type messages such as while events are being generated. The only restriction is that each message must be complete Chisholm, et al. Expires July 12, 2006 [Page 16] Internet-Draft NETCONF Event Notifications January 2006 The following sequence diagram demonstrates an example NETCONF session where after basic session establishment and capability exchange, NETCONF client (C), subscribes to receive event notifications. The NETCONF server (S), starts sending event notifications as events of interest happen within the system. The NETCONF client decides to change the characteristics of their event subscription so sends a command. Before the NETCONF server, receives this command, another event is generated and the NETCONF server starts to send the event notification. The NETCONF server finishes sending this event notification before processing the command and sending the reply. C S | | | capability exchange | |-------------------------->| |<------------------------->| | | | | |-------------------------->| |<--------------------------| | | | | |<--------------------------| | | | | |<--------------------------| | | | | |-------------------------->| (buffered) | | |<--------------------------| | | |<--------------------------| Chisholm, et al. Expires July 12, 2006 [Page 17] Internet-Draft NETCONF Event Notifications January 2006 4. XML Schema for Event Notifications This import accesses the xml: attribute groups for the xml:lang as declared on the error-message element. The unique identifier for this particular subscription within the session. A monotonically increasing integer. Starts at 0. Always increases by just one. Roll back to 0 after maximum value is reached. Chisholm, et al. Expires July 12, 2006 [Page 18] Internet-Draft NETCONF Event Notifications January 2006 Chisholm, et al. Expires July 12, 2006 [Page 19] Internet-Draft NETCONF Event Notifications January 2006 The date and time that the event notification was sent by the netconf server. Chisholm, et al. Expires July 12, 2006 [Page 21] Internet-Draft NETCONF Event Notifications January 2006 Chisholm, et al. Expires July 12, 2006 [Page 22] Internet-Draft NETCONF Event Notifications January 2006 5. Mapping to Application Protocols Currently, the NETCONF family of specification allows for running NETCONF over a number of application protocols, some of which support multiple configurations. Some of these options will be better suited for supporting event notifications then others. 5.1 SSH Session establishment and two-way messages are based on the NETCONF over SSH transport mapping [NETCONF-SSH] One-way messages are supported as follows: Once the session has been established and capabilities have been exchanged, the server may send complete XML documents to the NETCONF client containing rpc-one-way elements. No response is expected from the NETCONF client. As the other examples in [NETCONF-SSH] illustrate, a special character sequence, MUST be sent by both the client and the server after each XML document in the NETCONF exchange. This character sequence cannot legally appear in an XML document, so it can be unambiguously used to identify the end of the current document in the event notification of an XML syntax or parsing error, allowing resynchronization of the NETCONF exchange. The NETCONF over SSH session to receive an event notification might look like this: Chisholm, et al. Expires July 12, 2006 [Page 23] Internet-Draft NETCONF Event Notifications January 2006 123456 2 2000-01-12T12:13:14Z Fred Flinstone Ethernet0/0 1500 ]]> ]]> 5.2 BEEP Session establishment and two-way messages are based on the NETCONF over BEEP transport mapping NETCONF-BEEP 5.2.1 One-way Messages in Beep One-way messages can be supported either by mapping to the existing one-to-many BEEP construct or by creating a new one-to-none construct. This area is for future study. 5.2.1.1 One-way messages via the One-to-many Construct Messages in one-to-many exchanges: "rcp", "rpc-one-way", "rpc-reply" Chisholm, et al. Expires July 12, 2006 [Page 24] Internet-Draft NETCONF Event Notifications January 2006 Messages in positive replies: "rpc-reply", "rpc-one-way" 5.2.1.2 One-way messages via the One-to-none Construct Note that this construct would need to be added to an extension or update to 'The Blocks Extensible Exchange Protocol Core' RFC 3080. MSG/NoANS: the client sends a "MSG" message, the server, sends no reply. In one-to-none exchanges, no reply to the "MSG" message is expected. 5.3 SOAP Session management and message exchange are based on the NETCONF over SOAP transport mapping NETCONF-SOAP Note that the use of "persistent connections" "chunked transfer- coding" when using HTTP becomes even more important in the supporting of event notifications 5.3.1 A NETCONF over Soap over HTTP Example C: POST /netconf HTTP/1.1 C: Host: netconfdevice C: Content-Type: text/xml; charset=utf-8 C: Accept: application/soap+xml, text/* C: Cache-Control: no-cache C: Pragma: no-cache C: Content-Length: 465 C: C: C: C: C: C: C: C: C: C: The response: S: HTTP/1.1 200 OK S: Content-Type: application/soap+xml; charset=utf-8 Chisholm, et al. Expires July 12, 2006 [Page 25] Internet-Draft NETCONF Event Notifications January 2006 S: Content-Length: 917 S: S: S: S: S: S: S: S: 123456 S: S: S: S: S: And then some time later S: HTTP/1.1 200 OK S: Content-Type: application/soap+xml; charset=utf-8 S: Content-Length: 917 S: S: S: S: S: S: S: S: 123456 S: S: 2 S: 2000-01-12T12:13:14Z S: S: Fred Flinstone S: S: S: S: S: S: S: S: S: Ethernet0/0 S: 1500 Chisholm, et al. Expires July 12, 2006 [Page 26] Internet-Draft NETCONF Event Notifications January 2006 S: S: S: S: S: S: S: S: S: S: S: Chisholm, et al. Expires July 12, 2006 [Page 27] Internet-Draft NETCONF Event Notifications January 2006 6. Filtering examples The following section provides examples to illustrate the various methods of filtering content on an event notification subscription. 6.1 Event Classes The following example illustrates selecting all event notifications for EventClasses fault, state or config 6.2 Subtree Filtering XML subtree filtering is not well suited for creating elaborate filter definitions given that it only supports equality comparisons (e.g. in the event subtree give me all event notifications which have severity=critical or severity=major or severity=minor). Nevertheless, it may be used for defining simple notification forwarding filters as shown below. The following example illustrates selecting fault EventClass which have severities of critical, major, or minor. The filtering criteria evaluation is as follows: ((fault) & ((severity=critical) | (severity=major) | (severity = minor))) Chisholm, et al. Expires July 12, 2006 [Page 28] Internet-Draft NETCONF Event Notifications January 2006 critical major minor The following example illustrates selecting fault, state, config EventClasses which have severities of critical, major, or minor and come from card Ethernet0. The filtering criteria evaluation is as follows: ((fault | state | config) & ((fault & severity=critical) | (fault & severity=major) | (fault & severity = minor) | (card=Ethernet0))) Chisholm, et al. Expires July 12, 2006 [Page 29] Internet-Draft NETCONF Event Notifications January 2006 fault critical fault major fault minor Ethernet0 6.3 XPATH filters The following example illustrates selecting fault EventClass which have severities of critical, major, or minor. The filtering criteria evaluation is as follows: ((fault) & ((severity=critical) | (severity=major) | (severity = minor))) Chisholm, et al. Expires July 12, 2006 [Page 30] Internet-Draft NETCONF Event Notifications January 2006 (/event[eventClasses/fault] and (/event[severity="critical"] or /event[severity="major"] or /event[severity="minor"])) The following example illustrates selecting fault, state, config EventClasses which have severities of critical, major, or minor and come from card Ethernet0. The filtering criteria evaluation is as follows: ((fault | state | config) & ((fault & severity=critical) | (fault & severity=major) | (fault & severity = minor) | (card=Ethernet0))) ((/event[eventClasses/fault] or /event[eventClasses/state] or /event[eventClasses/config]) and ( (/event[eventClasses/fault] and /event[severity="critical"]) or (/event[eventClasses/fault] and /event[severity="major"]) or (/event[eventClasses/fault] and /event[severity="minor"]) or /event[card="Ethernet0"])) Chisholm, et al. Expires July 12, 2006 [Page 31] Internet-Draft NETCONF Event Notifications January 2006 7. Security Considerations To be determined once specific aspects of this solution are better understood. In particular, the access control framework and the choice of transport will have a major impact on the security of the solution Chisholm, et al. Expires July 12, 2006 [Page 32] Internet-Draft NETCONF Event Notifications January 2006 8. IANA Considerations Event Classes will likely be an IANA-managed resource. The initial set of values is defined in this specification. Chisholm, et al. Expires July 12, 2006 [Page 33] Internet-Draft NETCONF Event Notifications January 2006 9. Acknowledgements Thanks to Gilbert Gagnon and Greg Wilbur for providing their input into the early work on this document. In addition, the editors would like to acknowledge input at the Vancouver editing session from the following people: Orly Nicklass, James Bakstrieve, Yoshifumi Atarashi, Glenn Waters, Alexander Clemm, Dave Harrington, Dave Partain, Ray Atarashi and Dave Perkins. 10. References [NETCONF] Enns, R., "NETCONF Configuration Protocol", ID draft-ietf-netconf-prot-06, April 2005. [NETCONF BEEP] Lear, E. and K. Crozier, "Using the NETCONF Protocol over Blocks Extensible Exchange Protocol (BEEP)", ID draft-ietf-netconf-beep-05, March 2005. [NETCONF Datamodel] Chisholm, S. and S. Adwankar, "Framework for NETCONF Content", ID draft-chisholm-netconf-model-04.txt, October 2005. [NETCONF SOAP] Goddard, T., "Using the Network Configuration Protocol (NETCONF) Over the Simple Object Access Protocol (SOAP)", ID draft-ietf-netconf-soap-05, April 2005. [NETCONF SSH] Wasserman, M. and T. Goddard, "Using the NETCONF Configuration Protocol over Secure Shell (SSH)", ID draft-ietf-netconf-ssh-04.txt, April 2005. [URI] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifiers (URI): Generic Syntax", RFC 2396, August 1998. [XML] World Wide Web Consortium, "Extensible Markup Language (XML) 1.0", W3C XML, February 1998, . [refs.RFC2026] Bradner, S., "The Internet Standards Process -- Revision 3", RFC 2026, BCP 9, October 1996. [refs.RFC2119] Bradner, s., "Key words for RFCs to Indicate Requirements Chisholm, et al. Expires July 12, 2006 [Page 34] Internet-Draft NETCONF Event Notifications January 2006 Levels", RFC 2119, March 1997. [refs.RFC2223] Postel, J. and J. Reynolds, "Instructions to RFC Authors", RFC 2223, October 1997. [refs.RFC3080] Rose, M., "The Blocks Extensible Exchange Protocol Core", RFC 3080, March 2001. Authors' Addresses Sharon Chisholm Nortel 3500 Carling Ave Nepean, Ontario K2H 8E9 Canada Email: schishol@nortel.com Kim Curran Nortel 3500 Carling Ave Nepean, Ontario K2H 8E9 Canada Email: kicurran@nortel.com Hector Trevino Cisco Suite 400 9155 E. Nichols Ave Englewood, CO 80112 USA Email: htrevino@cisco.com Chisholm, et al. Expires July 12, 2006 [Page 35] Internet-Draft NETCONF Event Notifications January 2006 Appendix A. Potential Event Content This non-normative appendix explores possible content of event notifications. It provides field descriptions and indicates their applicability for the various event classes. Fields specific to configuration events (configuration event class) are provided in Appendix B. A.1 Event Identifier A unique event identifier provided for event correlation purposes. This field is used by management applications to identify events which are generated for a single event occurrence via different mechanisms (e.g. syslog, NETCONF). Ie, this event identifier could be included as content in a syslog or SNMP message to indicate that all the messages were generated from the same source event. Event Id values may be re-used across re-boots. Applicable event classes: All A.2 Resource Instance This field identifies the element/entity/object for which the event is applicable. Applicable event classes: All A.3 Event Time This field represents the time at which the action causing the generation of the event has taken place. Event time field is composed of two parts: event generation time and event sysUpTime. Event generation time follows the syslog TIMESTAMP format defined in draft-ietf-syslog-protocol-14.txt (derived from RFC3339 but with additional restrictions). Event sysUpTime is of XML type integer (0..4294967295) and it follows the same definition as sysUpTime (TimeTicks) defined in RFC3418 - "The time (in hundredths of a second) since the network management portion of the system was last re-initialized). Applicable event classes: All A.4 Perceived Severity The severity of the alarm as determined by the alarm detection point using the information it has available [RFC3877]. The values are cleared, indeterminate, critical, major, minor and warning. Chisholm, et al. Expires July 12, 2006 [Page 36] Internet-Draft NETCONF Event Notifications January 2006 Applicable event classes: fault A.5 Probable Cause This field provides further information describing the cause of the alarm . Allowed values for this field are the same as those listed in RFC3877 and are derived from ITU X.733 and ITU M.3100. Note that this concept is being evolved to be less linear, within the ITU-T, in X.733.1, a protocol-neutral version of X.733. It may make sense to consider alignment with this update on the concept of probable cause, instead of the one in RFC3877 and X.733. Applicable event classes: fault A.6 Specific Problem This parameter is optional. When present, it identifies further refinements to the Probable cause of the alarm. This definition follows ITU X.733 Applicable event classes: fault A.7 Trend Indication This parameter indicates the trend of the alarm against the managed resource Allowed values for this field are as specified in RFC3877 and follow the ITU X.733 value definitions Applicable event classes: fault A.8 Additional Alarm Text This parameter is provided to allow implementation to include a textual description of the alarm Applicable event classes: fault A.9 Threshold Identifier This field holds the identifier of the monitored variable for which the threshold was set. This is analogous to the alarmVariable OBJECT-TYPE in RFC2819. Applicable event classes: fault (useful for threshold crossing alarms) Chisholm, et al. Expires July 12, 2006 [Page 37] Internet-Draft NETCONF Event Notifications January 2006 A.10 Threshold Type This parameter is used to indicate the direction of the threshold crossing: rising, falling, or clear. Rising threshold type: This indicates that the value of a monitored variable has crossed the set threshold in the upwards direction. Only sent to indicate a problem Falling threshold type: This indicates that the value of a monitored variable has crossed the set threshold in the downwards direction. Only sent to indicate a problem. Clear threshold type: This indicates that the value of the monitored variable for which a threshold alarm had been previously issued as a result of crossing the set value either in the upwards or downwards direction has been restored to a value within an acceptable range (i.e. does not exceed the set threshold). Note that this differs from RFC2819. Applicable event classes: fault (useful in the case threshold crossing alarms) A.11 Observed Value The value of the monitored parameter (Threshold Identifier) for the last sampling period. This parameter follows the alarmValue definition in RFC2819. This field is in two parts - the value and the units of measure. Applicable event classes: fault (useful in the case threshold crossing alarms) A.12 State Change Information This parameter holds the name and values of the state attributes whose values have changed and are being reported. This is a parameter composed of three fields: Attribute Name, Old Value, and New Value. The definitions given in RFC4268 for state attributes and values are being followed. Applicable event classes: state Chisholm, et al. Expires July 12, 2006 [Page 38] Internet-Draft NETCONF Event Notifications January 2006 Appendix B. Configuration Event Class Notifications This non-normative appendix provides a detailed description of a configuration change event notification definition in support of the configuration operations, particularly those defined by the NETCONF protocol. B.1 Types of Configuration Events Configuration event notifications include: o All-triggered Configuration Events o NETCONF-triggered Configuration Events All-triggered Configuration events report on changes from the perspective of the managed resource, rather than the commands which created the configuration change. They are reported regardless of what specific method was used to initiate the change. They indicate that a change has occurred around hardware, software, services or other managed resources within a system. Specific events includes o Resource Added o Resource Removed o Resource Modified NETCONF-triggered events are those which correspond to the execution of explicit NETCONF operations. These include: o copy-config event * This is a data store level event generated following the successful completion of a copy-config operation. This represents the creation of a new configuration file or replacement of an existing one. o delete-config event * This is a data store level event generated following the successful completion of a delete-config operation. This represents the deletion of a configuration file. o edit-config event * This is an event generated following a change in configuration due to an edit-config operation, e.g., due to the completion of Chisholm, et al. Expires July 12, 2006 [Page 39] Internet-Draft NETCONF Event Notifications January 2006 an edit-config operation which successfully changed some part of the configuration. See edit-config error-options (stop-on- error, ignore-error, rollback-on-error) The contents of this event are dependent on the type of operation performed: edit- config (merge, replace, delete, create). This event is not intended to report completely unsuccessful configuration operations. o lock-config event * This is a data store level event generated following the successful locking of a configuration data store. o unlock-config event * This is a data store level event generated following the successful release of a lock previously held on a configuration data store. B.2 Config Event Notification Structure The table below lists the EventInfo parameters for a config event notification. Nomenclature: O - This is marked optional field because it is implementation/ notification category dependent. In some cases this may be user configurable. M - This is a mandatory field that must be included. Dependency on event class may exist as noted below Chisholm, et al. Expires July 12, 2006 [Page 40] Internet-Draft NETCONF Event Notifications January 2006 ----------------------------------------------------- Parameter Name Restrictions ----------------------------------------------------- EventInfo ----------------------------------------------------- EventID O ----------------------------------------------------- ResourceInstance M ----------------------------------------------------- ConfigChangeType M ----------------------------------------------------- TargetDataStore M ----------------------------------------------------- UserInfo O ----------------------------------------------------- UserName ----------------------------------------------------- SourceIndicator ----------------------------------------------------- TransactionId ----------------------------------------------------- CopyConfigInfo -- copy-config only ----------------------------------------------------- DataSource M ----------------------------------------------------- EditConfigInfo -- edit-config only ----------------------------------------------------- EventTime M ----------------------------------------------------- Context O ----------------------------------------------------- EnteredCommand M ----------------------------------------------------- NewConfig M ----------------------------------------------------- MergeReplaceInfo ----------------------------------------------------- OldConfig O ----------------------------------------------------- EventTime M ----------------------------------------------------- EventGenerationTime ----------------------------------------------------- EventSysUpTime ----------------------------------------------------- Chisholm, et al. Expires July 12, 2006 [Page 41] Internet-Draft NETCONF Event Notifications January 2006 B.3 Configuration Event Content The applicability of these fields to other event classes is for further study. B.3.1 Target Datastore Target datastore refers to the data store (startup, candidate, running) which was modified by the management operation. B.3.2 User Info This is used to convey information describing who originated the configuration event and the means for submitting the request. The user info field contains the following information: user Name: User id which was authorized to execute the associated management operation causing the generation of this event. source Indicator: Indicates the method employed to initiate the management operation telnet, NETCONF, console, etc. transaction Id: If available, this field contains a unique identifier for the associated management operation. This is implementation dependent and may require additional information to be communicated between server and client. A possible option is to make use of the message-id in the NETCONF rpc header B.3.3 Data Source The data source is used, for example, in the copy configuration command to indicated the source of information used in the copy operation Applicable Event Classes: configuration (useful for copy-config) B.3.4 Operation Operation is used, for example, in the edit configuration command to indicated the specific operation that has taken place - create, delete, merge, replace. Applicable Event Classes: configuration (useful for edit-config) B.3.5 Context The configuration sub-mode under which the command was executed. Chisholm, et al. Expires July 12, 2006 [Page 42] Internet-Draft NETCONF Event Notifications January 2006 Applicable Event Classes: configuration B.3.6 Entered Command The command entered and executed on the device. B.3.7 New Config The device's configuration following the successful execution of the entered command. Applicable Event Classes: configuration B.3.8 Old Config The configuration prior to the execution of the entered command. Applicable Event Classes: configuration B.3.9 Non-netconf commands in configuration notifications To support legacy implementations and for better integration with other deployed solutions on the box, sending information via netconf about configuration changes that were originated via other solutions, such as command line interfaces is necessary. In order to do this, the information in the message needs to be clearly tagged so that the consumer of the information knows what to expect. In addition, the creation of the subscription needs allow for the client to indicate whether this non-XML formatted information is of interest The latter is done by identifying the XML namespace under which the data syntax/schema is defined. A NETCONF client requests the format in which it wants the NETCONF server to issue the event notifications at subscription time by specifying the appropriate namespace under the Filter parameter in the operation. An example is provided below: B.4 Design Alternative B.4.1 Server Session Initiation Currently the NETCONF protocol requires session establishment to be Chisholm, et al. Expires July 12, 2006 [Page 43] Internet-Draft NETCONF Event Notifications January 2006 initiated by the NETCONF client. With the introduction of event notifications in NETCONF as well deployments which might require the "call-home" feature to get around firewall and/or NAT issues, the ability for a NETCONF server to initiate sessions becomes important. Other potential uses of this feature includes the following deployment scenario: NE registration/auto-configuration. The device is pre-configured with a target destination address (the management station's address) where it needs to register and download its configuration. When managing large numbers of devices (e.g. CPEs) this also allows for increased scalability since the management station does not need to maintain established sessions to all managed devices. This appendix proposes extensions to the event subscription session establishment procedures and related operations to allow for server session initiation. Note that the security implications of this approach, compared with more traditional, well understood models, is for further study. The subscription information as described in the body of this document indicates that it is transient in nature (i.e. it is not persisted and it is only applicable through the life of the session). This section describes additional functionality for persisting event subscription information and allowing the NETCONF server (e.g. network element) to initiate the event subscription session. QUICK SUMMARY: The , , operations would be used in same manner as described in doc. It may use useful to allow a client and server to re-establish an events subscription. This would result in another capability to allow session initiation by the server. B.4.2 Establishment In order to establish an event subscription, a client must issue a message request. Upon a successful response from the server (e.g. network element) the event subscription is established. With this modified persistent version of the subscription, the NETCONF server would maintain the subscription information as part of its configuration. B.4.3 Teardown A event subscription is torn down when a) the client issues a message and it is successfully processed by the server (i.e. the server issues a positive response) or b) the Chisholm, et al. Expires July 12, 2006 [Page 44] Internet-Draft NETCONF Event Notifications January 2006 NETCONF session carrying the event subscription goes down for any reason. If the subscription is not persistent, the user must create a new subscription with the exact same parameters as the original session. If instead, subscriptions were persistent, as part of the network element's configuration, the client simply needs to re-establish the session by specifying the subscription Id. B.4.4 Suspend And Resume Since the purpose of the operation is to stop event notification forwarding and due to its transient nature removes all subscription configuration; a different mechanism might be needed for shutting down the session but preserving the subscription information thus allowing the NETCONF server to re-establish the parameters and reproduce the subscription. The suspend and resume commands would allows a NETCONF client to suspend event notification forwarding without removing the existing subscription information. Operations and > are proposed for this purpose. Since event subscription information is now persistent, unsolicited session termination (i.e. other than command was issued. Event forwarding is resumed by sending a to the NETCONF server on a new connection. B.4.5 Lifecycle Configuration information associated with the event subscription (event classes and filters) could persist beyond the life of the event subscription session. (i.e. it is maintained by the network element as part of its configuration). This configuration information is subject to the behaviour of the datastore it resides in and may or may not persist across re-boots (e.g. it could be part of the running configuration but not the startup configuration). Chisholm, et al. Expires July 12, 2006 [Page 45] Internet-Draft NETCONF Event Notifications January 2006 Appendix C. NETCONF Event Notifications and Syslog This appendix describes the mapping between syslog message fields and NETCONF event notification fields. The purpose of this mapping is to provide an unambiguous mapping to enable consistent multi-protocol implementations as well as to enable future migration. The second part of the appendix describes an optional capability to embed an entire syslog message (hereafter referred to as syslog message(s) to avoid confusion with the message field in syslog) within a NETCONF event notification. C.1 Leveraging Syslog Field Definitions This section provides a semantic mapping between NETCONF event fields and syslog message fields. ------------------------------------------------------------------- | PRI | HEADER | MESSAGE | ------------------------------------------------------------------- | FACILITY | SEVERITY | TIMESTAMP | HOSTNAME | TAG CONTENT | ------------------------------------------------------------------- Figure 2 - syslog message (RFC3164) ------------------------------------------------------------------- | HEADER | STRUCTURED DATA | MESSAGE | ------------------------------------------------------------------- Figure 3 - syslog message (draft-ietf-syslog-protocol-14.txt) HEADER (Version, Facility, Severity, Truncate, Flag, TimeStamp, HostName, AppName, ProcId, MsgId) STRUCTURED DATA (Zero or more Structured Data Elements - SDEs) MESSAGE ( Text message ) Chisholm, et al. Expires July 12, 2006 [Page 46] Internet-Draft NETCONF Event Notifications January 2006 C.1.1 Field Mapping ------------------------------------------------------ RFC3164 Syslog ID NETCONF Event ------------------------------------------------------ VERSION ------------------------------------------------------ FACILITY FACILITY ------------------------------------------------------ SEVERITY SEVERITY PerceivedSeverity ------------------------------------------------------ TRUNCATE FLAG ------------------------------------------------------ TIMESTAMP TIMESTAMP EventTime ------------------------------------------------------ HOSTNAME HOSTNAME EventOrigin ------------------------------------------------------ TAG APP-NAME EventOrigin ------------------------------------------------------ PROC-ID ------------------------------------------------------ MSG-ID ------------------------------------------------------ CONTENT CONTENT AdditionalText ------------------------------------------------------ Figure 4 - syslog to NETCONF Event field mapping Notes: VERSION: Schema version is found in XML Schema namespace. However, no correspondence to syslog. FACILITY: No well defined semantics for this field. Therefore not used at this time. TRUNCATE: Not applicable. NETCONF events must be complete XML documents therefore cannot be truncated. TIME: TIMESTAMP in syslog ID is derived from RFC3339 but with additional restrictions PROC-ID: No equivalent field CONTENT: This is a free form text field with not defined semantics. The contents of this field may be included in the AdditionalText field. Chisholm, et al. Expires July 12, 2006 [Page 47] Internet-Draft NETCONF Event Notifications January 2006 C.1.2 Severity Mapping The severity value mappings stated in (draft-ietf-syslog-protocol-14) are used: ITU Perceived Severity syslog SEVERITY Critical Alert Major Critical Minor Error Warning Warning Indeterminate Notice Cleared Notice Figure 5. ITU PerceivedSeverity to syslog SEVERITY mapping. C.2 Syslog within NETCONF Events C.2.1 Motivation The syslog protocol (RFC3164) is widely used by equipment vendors as a means to deliver event messages. Due to the widespread use of syslog as well as a potential phased availability and coverage of NETCONF events by equipment vendors, it is envisioned that users will also follow a phased migration. As a way to facilitate migration and at the same time allow equipment vendors to provide comprehensive event coverage over a NETCONF event subscription session, syslog messages could be embedded in their entirety within the body of a NETCONF event notification. The information provided in this appendix describes a mechanism to leverage syslog messages for the purpose of complementing the available NETCONF event notification set. The intent is to promote the use of the NETCONF interface and not to simply provide a wrapper and additional delivery mechanism for syslog messages. NETCONF events are intended to be well defined and structured, therefore providing an advantage over the unstructured and often times arbitrarily defined syslog messages (i.e. the message field). Covered herein is the syslog protocol as defined in RFC3164 and draft-ietf-syslog-protocol-14.txt. C.2.2 Embedding syslog messages in a NETCONF Event When event notifications are supported, the default behaviour for a NETCONF server is to send NETCONF event notifications over an established event subscription. As an option, the NETCONF server may embed a syslog message in its entirety (e.g. RFC3164 - PRI, Header, Chisholm, et al. Expires July 12, 2006 [Page 48] Internet-Draft NETCONF Event Notifications January 2006 and Message fields), placing it within the Event Info field (SyslogInfo sub-field) - see Figure 1. _____________________________________________________ | NETCONF Event Header | Data | |________________________|___________________________| | | Event Info | |________________________|___________________________| | | v v ____________________________ | Event Fields | SyslogInfo | |___________________________| Figure 1 - Embedding syslog in a NETCONF Event Notifications C.2.3 Supported Forwarding Options Three event forwarding options may be supported by the NETCONF server: a) XML only (mandatory if NETCONF events capability is supported) b) XML and syslog (Optional) c) syslog only (optional) Note to the reader: Option "a" above refers to event notification messages defined for use over the NETCONF protocol. While their use is not necessarily limited to NETCONF protocol, they are referred to as "NETCONF XML-event" in the remainder of this section simply to avoid ambiguity. C.2.3.1 XML and Syslog option - Forwarding Behaviour It is possible, due to coverage, for a given NETCONF implementation to not support a comprehensive set of NETCONF event notifications. Therefore, it is possible for a given event to trigger the generation of a syslog message without a NETCONF-aware counterpart. In such situations, the NETCONF server could form a NETCONF event notification, embed the syslog message in the SyslogInfo field and forward the NETCONF event notifications to all subscribed destinations. Otherwise, both NETCONF event and syslog messages must be included in the Event Info field. C.2.3.2 Event Class Identification The event class field is found in the NETCONF event header information as described in the main body of this document. It conveys information describing that type of event for which the event notification is generated and lets the consumer of the message know Chisholm, et al. Expires July 12, 2006 [Page 49] Internet-Draft NETCONF Event Notifications January 2006 what to expect. NETCONF event notifications which only contain a syslog message (Options b or c) must have the EventClass field set to "information". [Editor's Note: This needs to be thought through. It may not be the best option.] The NETCONF client parses the message in the same manner as any other message, finds the normal fields empty [Editor's Note: or not present?] and either proceeds to parse the SyslogInfo field or hands the syslog message to the entity responsible for processing syslog messages. C.2.3.3 Event Subscription Options A NETCONF client may request subscription to options b) XML and syslog or c) syslog only listed in "Supported Forwarding Options" at subscription time via the user-specified filter. The FILTER or NAMED FILTER parameter in . As previously indicated, the default behaviour is to forward NETCONF XML only event notifications. C.2.3.4 Supported Forwarding Option Discovery A potential means for a NETCONF server to convey its feature set support is via capabilities. However, in this particular case, the event content is not a protocol feature therefore other means are needed. A future version of this document will address this issue. Chisholm, et al. Expires July 12, 2006 [Page 50] Internet-Draft NETCONF Event Notifications January 2006 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. The IETF has been notified of intellectual property rights claimed in regard to some or all of the specification contained in this document. For more information consult the online list of claimed rights. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2006). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Chisholm, et al. Expires July 12, 2006 [Page 51] Internet-Draft NETCONF Event Notifications January 2006 Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Chisholm, et al. Expires July 12, 2006 [Page 52]