Network Working Group S. Chisholm Internet-Draft Nortel Intended status: Standards Track H. Trevino Expires: January 9, 2008 Cisco July 8, 2007 NETCONF Event Notifications draft-ietf-netconf-notification-08.txt.pre-release 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 January 9, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Chisholm & Trevino Expires January 9, 2008 [Page 1] Internet-Draft NETCONF Event Notifications July 2007 Abstract This document defines mechanisms which provide an asynchronous message notification delivery service for the NETCONF protocol. This is an optional capability built on top of the base NETCONF definition. This document defines the capabilities and operations necessary to support this service. Chisholm & Trevino Expires January 9, 2008 [Page 2] Internet-Draft NETCONF Event Notifications July 2007 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Definition of Terms . . . . . . . . . . . . . . . . . . . 4 1.2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . 5 1.3. Event Notifications in NETCONF . . . . . . . . . . . . . . 5 1.4. Requirements . . . . . . . . . . . . . . . . . . . . . . . 6 2. Notification-Related Operations . . . . . . . . . . . . . . . 7 2.1. Subscribing to Receive Event Notifications . . . . . . . . 7 2.1.1. . . . . . . . . . . . . . . . . 7 2.2. Sending Event Notifications . . . . . . . . . . . . . . . 9 2.2.1. . . . . . . . . . . . . . . . . . . . . 9 2.3. Terminating the Subscription . . . . . . . . . . . . . . . 10 3. Supporting Concepts . . . . . . . . . . . . . . . . . . . . . 11 3.1. Capabilities Exchange . . . . . . . . . . . . . . . . . . 11 3.1.1. Capability Identifier . . . . . . . . . . . . . . . . 11 3.1.2. Capability Example . . . . . . . . . . . . . . . . . . 11 3.2. Event Streams . . . . . . . . . . . . . . . . . . . . . . 11 3.2.1. Event Stream Definition . . . . . . . . . . . . . . . 12 3.2.2. Event Stream Content Format . . . . . . . . . . . . . 13 3.2.3. Default Event Stream . . . . . . . . . . . . . . . . . 13 3.2.4. Event Stream Sources . . . . . . . . . . . . . . . . . 13 3.2.5. Event Stream Discovery . . . . . . . . . . . . . . . . 13 3.3. Notification Replay . . . . . . . . . . . . . . . . . . . 15 3.3.1. Overview . . . . . . . . . . . . . . . . . . . . . . . 15 3.3.2. Creating a Subscription with Replay . . . . . . . . . 16 3.3.3. Replay Complete Notification . . . . . . . . . . . . . 16 3.4. Notification Management Schema . . . . . . . . . . . . . . 16 3.5. Subscriptions Data . . . . . . . . . . . . . . . . . . . . 19 3.6. Filter Mechanics . . . . . . . . . . . . . . . . . . . . . 19 3.6.1. Filtering . . . . . . . . . . . . . . . . . . . . . . 19 3.7. Message Flow . . . . . . . . . . . . . . . . . . . . . . . 19 4. XML Schema for Event Notifications . . . . . . . . . . . . . . 21 5. Filtering Examples . . . . . . . . . . . . . . . . . . . . . . 25 5.1. Subtree Filtering . . . . . . . . . . . . . . . . . . . . 25 5.2. XPATH filters . . . . . . . . . . . . . . . . . . . . . . 28 6. Security Considerations . . . . . . . . . . . . . . . . . . . 30 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 31 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 32 9. Normative References . . . . . . . . . . . . . . . . . . . . . 33 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 34 A.1. Version -08 . . . . . . . . . . . . . . . . . . . . . . . 34 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 37 Intellectual Property and Copyright Statements . . . . . . . . . . 38 Chisholm & Trevino Expires January 9, 2008 [Page 3] Internet-Draft NETCONF Event Notifications July 2007 1. Introduction [NETCONF] can be conceptually partitioned into four layers: Layer Example +-------------+ +----------------------------------------+ | Content | | Configuration data | +-------------+ +----------------------------------------+ | | +-------------+ +-------------------------------------------+ | Operations | | , | +-------------+ +-------------------------------------------+ | | | +-------------+ +-----------------------------+ | | RPC | | , | | +-------------+ +-----------------------------+ | | | | +-------------+ +------------------------------------------+ | Transport | | BEEP, SSH, SSL, console | | Protocol | | | +-------------+ +------------------------------------------+ Figure 1 This document defines mechanisms which provide an asynchronous message notification delivery service for the [NETCONF] protocol. This is an optional capability built on top of the base NETCONF definition. This memo defines the capabilities and operations necessary to support this service. 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 [RFC2119]. Element: An [XML] Element. Subscription: An agreement and method to receive event notifications over a NETCONF session. A concept related to the delivery of notifications (if any to send) involving destination and selection of notifications. It is bound to the lifetime of a session. Operation: This term is used to refer to NETCONF protocol operations [NETCONF]. Specifically within this document, operation refers to NETCONF protocol operations defined in support of NETCONF notifications. Chisholm & Trevino Expires January 9, 2008 [Page 4] Internet-Draft NETCONF Event Notifications July 2007 Event: 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 to interested parties to notify them that this event has occurred. Replay: The ability to send/re-send previously logged notifications upon request. These notifications are sent asynchronously. This feature is implemented by the NETCONF server and invoked by the NETCONF client. Stream: An event stream is a set of event notifications matching some forwarding criteria and it is available to NETCONF clients for subscription. Filter: A parameter that indicates which subset of all possible events are of interest. 1.2. Motivation The motivation for this work is to enable the sending of asynchronous messages that are consistent with the data model (content) and security model used within a NETCONF implementation. 1.3. Event Notifications in NETCONF 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 the subscription terminates for some other reason. 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. A NETCONF server is will not read RPC requests, by default, on the session associated with the subscription until the notification subscription is done. A capability may be advertised to announce that a server is able to process RPCs while a notification stream is active on a session. The behaviour of such a capability is outside the scope of this document. Chisholm & Trevino Expires January 9, 2008 [Page 5] Internet-Draft NETCONF Event Notifications July 2007 1.4. Requirements The following requirements have been addressed by the solution: o Initial release should ensure it supports notification in support of configuration operations o Data content must not preclude the use of the same data model as used in configuration o Solution should support a reasonable message size limit (ie, not too short) o Solution should provide reliable delivery of notifications o Solution should provide a subscription mechanism (A NETCONF server does not send notifications before being asked to do so and the NETCONF client initiates the flow of notifications) o Solution should provide a filtering mechanism within the NETCONF server o Solution should send sufficient information in a notification so that it can be analyzed independent of the transport mechanism (data content fully describes a notification; protocol information is not needed to understand a notification) o Solution should support replay of locally logged notifications Chisholm & Trevino Expires January 9, 2008 [Page 6] Internet-Draft NETCONF Event Notifications July 2007 2. Notification-Related Operations 2.1. Subscribing to Receive Event Notifications 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. Content for an event notification subscription can be selected by applying user-specified filters. 2.1.1. Description: This operation initiates an event notification subscription which will send asynchronous event notifications to the initiator of the command until the subscription terminates. Parameters: Stream: An optional parameter that indicates which stream of events is of interest. If not present, then events in the default NETCONF stream 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. See section 3.6 for more information on filters. Start Time: A parameter used to trigger the replay feature and indicate that the replay should start at the time specified. If startTime is not present, this is not a replay subscription. It is valid to specify start times that are later than the current time. If the startTime specified is earlier than the log can support, the replay will begin with the earliest available notification. This parameter is of type dateTime. Chisholm & Trevino Expires January 9, 2008 [Page 7] Internet-Draft NETCONF Event Notifications July 2007 Stop Time: An optional parameter used with the optional replay feature to indicate the newest notifications of interest. If stop time is not present, the notifications will continue until the subscription is terminated. Must be used with and be later than 'startTime'. It is valid to specify stop times that are later than the current time. This parameter is of type dateTime. Positive Response: If the NETCONF server can satisfy the request, the server sends an element. Negative Response: An element is included within the if the request cannot be completed for any reason. Subscription requests will fail if a filter with invalid syntax is provided or if the name of a non-existent profile or stream is provided. If a stopTime is specified in a request without having specified a startTime the following error is returned: Tag: missing-element Error-type: protocol Severity: error Error-info: : startTime Description: An expected element is missing. If the optional replay feature is requested but it is not supported by the NETCONF server, the following error is returned: Tag: operation-failed Error-type: protocol Severity: error Error-info: none Chisholm & Trevino Expires January 9, 2008 [Page 8] Internet-Draft NETCONF Event Notifications July 2007 Description: Request could not be completed because the requested operation failed for some reason not covered by any other error condition 2.1.1.1. Usage Example Figure 2 2.2. Sending Event Notifications Once the subscription has been set up, the NETCONF server sends the event notifications asynchronously over the connection. 2.2.1. Description: An event notification is sent to the client who initiated a command asynchronously when an event of interest (i.e., meeting the specified filtering criteria) to them has occurred. An event notification is a complete and well-formed XML document. Note that is not an RPC method but rather the top level element identifying the one way message as a notification. Parameters: Contains notification-specific tagged content. The content of the data tag is beyond the scope of this document. Response: No response. Not applicable. Chisholm & Trevino Expires January 9, 2008 [Page 9] Internet-Draft NETCONF Event Notifications July 2007 2.3. Terminating the Subscription Closing of the event notification subscription can be done by terminating the NETCONF session ( ) or the underlying transport session. If a stop time is provided when the subscription is created, then the subscription will terminate after the stop time is reached. In this case, the NETCONF session will still be an active session. Chisholm & Trevino Expires January 9, 2008 [Page 10] Internet-Draft NETCONF Event Notifications July 2007 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. 3.1.1. Capability Identifier "urn:ietf:params:netconf:capability:notification:1.0" 3.1.2. Capability Example 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 4 Figure 3 3.2. Event Streams An event stream is defined as a set of event notifications matching some forwarding criteria. The diagram depicted in Figure 2 illustrates the notification flow and concepts identified in this document. The following is observed from the diagram below: System components (c1..cn) generate event notifications which are passed to a central component for classification and distribution. The central component inspects each event notification and matches the event notification against the set of stream definitions. When a match occurs, the event notification is considered to be a member of that event stream (stream 1..stream n). An event notification may be part of multiple event streams. When a NETCONF client subscribes to a given event stream, user- Chisholm & Trevino Expires January 9, 2008 [Page 11] Internet-Draft NETCONF Event Notifications July 2007 defined filters, if applicable, are applied to the event stream and matching event notifications are forwarded to the NETCONF server for distribution to subscribed NETCONF clients. For more information on filters, see section 3.6. A notification logging service may also be available, in which case, the central component logs notifications. The NETCONF server may later retrieve logged notifications via the optional replay feature. For more information on replay, see section 3.3. +----+ | c1 |----+ available streams +----+ | +---------+ +----+ | |central |-> stream 1 | c2 | +--->|event |-> stream 2 filter +-------+ +----+ | |processor|-> NETCONF stream ----->|netconf| ... | | |-> stream n |server | System | +---------+ +-------+ Components| | /\ ... | | || +----+ | | (------------) || | cn |----+ | (notification) || +----+ +-----> ( logging ) || ( service ) || (------------) || || || \/ +-------+ |netconf| |client | +-------+ Figure 4 3.2.1. Event Stream Definition Event streams are predefined on the managed device. The configuration of event streams is outside the scope of this document. However, it is envisioned that event streams are either pre- established by the vendor (pre-configured) or user configurable (e.g., part of the device's configuration) or both. Device vendors may allow event stream configuration via NETCONF protocol (i.e., edit-config operation). Chisholm & Trevino Expires January 9, 2008 [Page 12] Internet-Draft NETCONF Event Notifications July 2007 3.2.2. Event Stream Content Format The contents of all event streams made available to a NETCONF client (i.e., the notification sent by the NETCONF server) must be encoded in XML. 3.2.3. 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. The definition of the event notifications and their contents for this event stream is outside the scope of this document. 3.2.4. Event Stream Sources With the exception of the default event stream (NETCONF notifications) specification of additional event stream sources (e.g., SNMP, syslog, etc.) is outside the scope of this document. NETCONF server implementations may leverage any desired event stream source in the creation of supported event streams. 3.2.5. Event Stream Discovery A NETCONF client retrieves the list of supported event streams from a NETCONF server using the RPC request. 3.2.5.1. Name Retrieval using operation The list of available event streams is retrieved by requesting the subtree via a operation. Available event streams for the requesting session are returned in the reply containing the and elements, where the element is mandatory and its value is unique within the scope of a NETCONF server. The returned list must only include the names of those event streams for which the NETCONF session has sufficient privileges. The NETCONF session privileges are determined via access control mechanisms which are beyond the scope of this document. An empty reply is returned if there are no available event streams. The information is retrieved by requesting the subtree via a operation. Chisholm & Trevino Expires January 9, 2008 [Page 13] Internet-Draft NETCONF Event Notifications July 2007 Example: Retrieving available event stream list using operation: Figure 5 The NETCONF server returns a list of event streams available for subscription: NETCONF, SNMP, and syslog-critical in this example. NETCONF Default netconf event stream true 2007-07-08T00:00:00Z SNMP SNMP notifications false syslog-critical Critical and higher severity true 2007-07-01T00:00:00Z Chisholm & Trevino Expires January 9, 2008 [Page 14] Internet-Draft NETCONF Event Notifications July 2007 Figure 6 3.2.5.2. Event Stream Subscription A NETCONF client may request from the NETCONF server the list of event streams available to this session and then issue a request with the desired event stream name. Omitting the event stream name from the request results in subscription to the default NETCONF event stream. 3.2.5.2.1. Filtering Event Stream Contents The set of event notifications delivered in an event stream may be further refined by applying a user-specified filter at subscription creation time ( ). This is a transient filter associated with the event notification subscription and does not modify the event stream configuration. XPATH support for the Notification capability is advertised as part of the normal XPATH capability advertisement. If XPATH support is advertised via the XPATH capability then XPATH is supported for notification filtering and if this capability is not advertised, then XPATH is not supported for notification filtering. 3.3. Notification Replay 3.3.1. Overview Replay is the ability to create an event subscription that will resend recently generated notifications, or in some cases send them for the first time to a particular NETCONF client. These notifications are sent the same way as normal notifications. A replay of notifications is specified by including an optional parameter to the subscription command that indicates the start time of the replay. The end time is specified using the optional stopTime parameter. If not present, notifications will continue to be sent until the subscription is terminated. A notification stream that supports replay is not expected to have an unlimited supply of saved notifications available to accommodate any replay request. The actual number of stored notifications available for retrieval at any given time is a NETCONF server implementation specific matter. Control parameters for this aspect of the feature are outside the scope of the current document. Chisholm & Trevino Expires January 9, 2008 [Page 15] Internet-Draft NETCONF Event Notifications July 2007 Replay is dependent on a notification stream supporting some form of notification logging, although it puts no restrictions on the size or form of the log, nor where it resides within the device. Whether or not a stream supports replay can be discovered by doing a operation on the eventStreams element of the Notification Management Schema. This schema also provides the replayLogStartTime element to indicate the earliest available logged notification. 3.3.2. Creating a Subscription with Replay This feature uses optional parameters to the command called 'startTime' and 'stopTime'. 'startTime' identifies the earliest date and time of interest for event notifications being replayed and also indicates that a subscription will be providing replay of notifications. Events generated before this time are not matched. 'stopTime' specifies the latest date and time of interest for event notifications being replayed. If it is not present, then notifications will continue to be sent until the subscription is terminated. Note that startTime and stopTime are associated with the time an event was generated by the system. A replayComplete notification is sent to indicate that all of the replay notifications have been sent. If this subscription has a stop time, then this session becomes a normal NETCONF session again. In the case of a subscription without a stop time, after the replayComplete notification has been sent, it can be expected that any notifications generated since the start of the subscription creation will be sent followed by notifications as they arise naturally within the system. 3.3.3. Replay Complete Notification The replayComplete notification is the last notification sent over a replay subscription. It indicates that replay is complete. After this notification is received the subscription is terminated and the session becomes normal command-response NETCONF session. The replayComplete can not be filtered out. It will always be sent on a relay subscription that specified a stop time. 3.4. Notification Management Schema This Schema is used to learn about the event streams supported on the system. It also contains the definition of the replayComplete, which is sent to indicate that an event replay has sent all applicable notifications." Chisholm & Trevino Expires January 9, 2008 [Page 16] Internet-Draft NETCONF Event Notifications July 2007 A schema that can be used to learn about current event streams. It also contains the replayComplete notification. The list of event streams supported by the system. When a query is issued, the returned set of streams is determined based on user privileges. Stream name and description. Chisholm & Trevino Expires January 9, 2008 [Page 17] Internet-Draft NETCONF Event Notifications July 2007 The start time of the log used to support the replay function. This object MUST be present if replay is supported. This notification is sent to signal the end of a replay portion of a subscription. Figure 7 Chisholm & Trevino Expires January 9, 2008 [Page 18] Internet-Draft NETCONF Event Notifications July 2007 3.5. Subscriptions Data While it may be possible to retrieve information about subscriptions via a get operation, subscriptions are not stored configuration. They are non-persistent state information and their lifetime is defined by their session. 3.6. Filter Mechanics When multiple filter elements are specified, they are applied collectively, so event notifications need to pass all specified filters in order to be sent to the subscriber. If a filter element is specified to look for data of a particular value, and the data item is not present within a particular event notification for its value to be checked against, the notification 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. The order that filter elements are applied does not matter since the resulting set of notifications is the intersection of the set of notifications that pass each filtering criteria. 3.6.1. Filtering Filtering is explicitly stated when the event notification subscription is created. This is specified via the 'filter' parameter. Filters only exist as parameters to the subscription. 3.7. Message Flow Chisholm & Trevino Expires January 9, 2008 [Page 19] Internet-Draft NETCONF Event Notifications July 2007 The following figure depicts message flow between a NETCONF client (C) and NETCONF server (S) in order create a subscription and begin the flow of notifications. It is possible that many rpc/rpc-reply sequences occur before the subscription is created or after a stopTime in a replay subscription, but this is not depicted in the figure. C S | | | capability exchange | |-------------------------->| |<------------------------->| | | | | |-------------------------->| |<--------------------------| | | | | | | |<--------------------------| | | | | |<--------------------------| | | | | | | | | |<--------------------------| | | | | Figure 8 Chisholm & Trevino Expires January 9, 2008 [Page 20] Internet-Draft NETCONF Event Notifications July 2007 4. XML Schema for Event Notifications The following [XML Schema] defines NETCONF Event Notifications. This import accesses the xml: attribute groups for the xml:lang as declared on the error-message element. An optional parameter that indicates Chisholm & Trevino Expires January 9, 2008 [Page 21] Internet-Draft NETCONF Event Notifications July 2007 which stream of events is of interest. If not present, then events in the default NETCONF stream will be sent. 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. A parameter used to trigger the replay feature and indicates that the replay should start at the time specified. If start time is not present, this is not a replay subscription. An optional parameter used with the optional replay feature to indicate the newest notifications of interest. If stop time is not present, the notifications will continue until the subscription is terminated. Must be used with 'startTime'. Chisholm & Trevino Expires January 9, 2008 [Page 22] Internet-Draft NETCONF Event Notifications July 2007 The name of an event stream. The command to create a notification subscription. It takes as argument the name of the notification stream and filter or profile information. All of those options limit the content of the subscription. In addition, there are two time-related parameters startTime and stopTime which can be used to select the time interval of interest. Chisholm & Trevino Expires January 9, 2008 [Page 23] Internet-Draft NETCONF Event Notifications July 2007 Figure 9 Chisholm & Trevino Expires January 9, 2008 [Page 24] Internet-Draft NETCONF Event Notifications July 2007 5. Filtering Examples The following section provides examples to illustrate the various methods of filtering content on an event notification subscription. 5.1. Subtree Filtering XML subtree filtering is not well suited for creating elaborate filter definitions given that it only supports equality comparisons and logical OR operations (e.g., in an 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 event notification forwarding filters as shown below. In order to illustrate the use of filter expressions it is necessary to assume some of the event notification content. The examples herein assume that the event notification schema definition has an element at the top level that contains one or more child elements consisting of the event class (e.g., fault, state, config, etc.) reporting entity and either severity or operational state. Chisholm & Trevino Expires January 9, 2008 [Page 25] Internet-Draft NETCONF Event Notifications July 2007 Sample event list fault Ethernet0 major fault Ethernet2 critical fault ATM1 minor state Ethernet0 enabled Figure 10 The following example illustrates selecting events which have severities of critical, major, or minor (presumably fault events). The filtering criteria evaluation is as follows: ((severity=critical) | (severity=major) | (severity=minor)) Chisholm & Trevino Expires January 9, 2008 [Page 26] Internet-Draft NETCONF Event Notifications July 2007 fault critical fault major fault minor Figure 11 The following example illustrates selecting state or config EventClasses or fault events that are related to card Ethernet0. The filtering criteria evaluation is as follows: ( state | config | fault & card=Ethernet0) Chisholm & Trevino Expires January 9, 2008 [Page 27] Internet-Draft NETCONF Event Notifications July 2007 fault state config fault Ethernet0 5.2. XPATH filters The following [XPATH] example illustrates selecting fault EventClass notifications that have severities of critical, major, or minor. The filtering criteria evaluation is as follows: ((fault) & ((severity=critical) | (severity=major) | (severity = minor))) Chisholm & Trevino Expires January 9, 2008 [Page 28] Internet-Draft NETCONF Event Notifications July 2007 Figure 13 The following example illustrates selecting state and config EventClasses or fault events that have severities of critical, major, or minor or come from card Ethernet0. The filtering criteria evaluation is as follows: (( state | config) & ((fault & severity=critical) | (fault & severity=major) | (fault & severity = minor) | (fault & card=Ethernet0))) Figure 14 Chisholm & Trevino Expires January 9, 2008 [Page 29] Internet-Draft NETCONF Event Notifications July 2007 6. Security Considerations The security considerations from the base [NETCONF] document apply also to the Notification capability. The access control framework and the choice of transport will have a major impact on the security of the solution. The elements are never sent before the transport layer and the netconf layer (capabilities exchange) have been established, and the manager has been identified and authenticated. It is recommended that care be taken to ensure the secure operation of the following commands: o invocation o read-only data models o read-write data models o notification content One issue related to the notifications draft is the transport of data from non-netconf streams, such as syslog and SNMP. This data may be more vulnerable (or is not more vulnerable) when being transported over netconf than when being transported using the protocol normally used for transporting it, depending on the security credentials of the two subsystems. The NETCONF server is responsible for providing access control to stream content. If a user does not have permission to view content via other NETCONF operations it does not have permission to access that content via Notifications. If a user is not permitted to view one element in the content of the notification, the notification is not sent to that user. If a subscription is created with a stopTime, the NETCONF session will return to being a normal command-response NETCONF session when the replay is completed. It is the responsibility of the NETCONF client to close off this session when it is no longer of use. Chisholm & Trevino Expires January 9, 2008 [Page 30] Internet-Draft NETCONF Event Notifications July 2007 7. IANA Considerations This document registers two URIs for the NETCONF XML namespace in the IETF XML registry [RFC3688]. Following the format in RFC 3688, IANA has made the following registration. URI: urn:ietf:params:netconf:capability:notification:1.0 URI: urn:ietf:params:xml:ns:netmod:notification Registrant Contact: The IESG. XML: N/A, the requested URI is an XML namespace. Chisholm & Trevino Expires January 9, 2008 [Page 31] Internet-Draft NETCONF Event Notifications July 2007 8. Acknowledgements Thanks to Gilbert Gagnon, Greg Wilbur and Kim Curran 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 Balestriere, Yoshifumi Atarashi, Glenn Waters, Alexander Clemm, Dave Harrington, Dave Partain, Ray Atarashi and Dave Perkins and the following additional people from the Montreal editing session: Balazs Lengyel, Phil Shafer, Rob Enns, Andy Bierman, Dan Romascanu, Bert Wijnen, Simon Leinen, Juergen Schoenwaelder, Hideki Okita, Vincent Cridlig, Martin Bjorklund, Olivier Festor, Radu State, Brian Trammell, William Chow. Chisholm & Trevino Expires January 9, 2008 [Page 32] Internet-Draft NETCONF Event Notifications July 2007 9. Normative References [NETCONF] Enns, R., "NETCONF Configuration Protocol", RFC 4741, December 2006. [RFC2026] Bradner, S., "The Internet Standards Process -- Revision 3", RFC 2026, BCP 9, October 1996. [RFC2119] Bradner, s., "Key words for RFCs to Indicate Requirements Levels", RFC 2119, March 1997. [RFC2223] Postel, J. and J. Reynolds, "Instructions to RFC Authors", RFC 2223, October 1997. [RFC3688] Bradner, s., "The IETF XML Registry", RFC 3688, January 2004. [XML] World Wide Web Consortium, "Extensible Markup Language (XML) 1.0", W3C XML, February 1998, . [XML Schema] Fallside, D. and P. Walmsley, "XML Schema Part 0: Primer Second Edition", W3C XML Schema, October 2004. [XPATH] Clark, J. and S. DeRose, "XML Path Language (XPath) Version 1.0", W3C http://www.w3.org/TR/1999/REC-xpath-19991116, November 1999. Chisholm & Trevino Expires January 9, 2008 [Page 33] Internet-Draft NETCONF Event Notifications July 2007 Appendix A. Change Log A.1. Version -08 1. Removed named profiles 2. Removed eventClass that was accidentally included in the definition of the replayComplete notification 3. Deleted data wrapper from notification 4. Changed replayLogStartTime to have a minOccurs of 0. It will only be there when replay is supported. Verify examples in section 3.2.5.1 are correct with respect to this element. 5. Error codes in section 2.1.1, fixed formatting issue 6. Moved replayComplete to not be under 7. Section 2.1, fixed capitalization 8. In figure 4, the line was pushed out by 'system components', fixed this. 9. On page 8, replaced "If the startTime specified is earlier then the" with 'If the startTime specified is earlier than the" 10. Updated some name spaces and schemaLocations as per Andy's June 3rd email. 11. Added discussion of replayLogStartTime to draft in section 3.3.1 as follows "Whether or not a stream supports replay can be discovered by doing a operation on the eventStreams elements of the Notification Management Schema. This schema also provides the replayLogStartTime element to indicate the earliest available logged notification." 12. Removed most of the uses of the phrase 'Note that'. I kept two uses that prevent sentences from starting with either a lower case letter or an angle bracket. 13. In section 3.6 replaced "it will be filtered out" with "the notification will be filtered out" 14. In section 3.4, replaced "and the query" with "and to query" 15. Replaced 3 instances of "replay complete notification" with "replayComplete notification" Chisholm & Trevino Expires January 9, 2008 [Page 34] Internet-Draft NETCONF Event Notifications July 2007 16. In section 3.3.2, replaced "normal NETCONF session" with "normal command-response NETCONF session" 17. In section 3.3.1, replaced "create an event subscription that will resend recently generated notification" with "create an event subscription that will resend recently generated notification, or is some cases send them for the first time to a particular NETCONF client." 18. In section 3.2.5.2, s/available event streams to/event streams available to/ 19. In one spot, changed snmp to SNMP (the other gets deleted) 20. In section 3.2.5.1 s/where element is/where the element is/ 21. In section 3.2.5.1, clarified that "value is unique" - within the scope of a NETCONF server. 22. In section 2.1.1, clarified that stopTime cannot preceded start time. 23. In section 2.1.1, in Start Time s/indicates/indicate/ 24. In section 2.1.1, in Filter: s/This is mutually exclusive/The filter parameter is mutually exclusive/ ("this" could refer to the behavior described in the previous sentence.) 25. In section 1.4, third bullet, replaced "syslog and SNMP are rather constrained in terms of message sizes)" with (ie, not too short) 26. In section 1.4, made all bullets start with capital leters. 27. Added definition of Filter to section 1.1 28. In section 1.1, improved the definition of subscription with "An agreement and method to receive event notifications over a NETCONF session." 29. In section 1.1, in the definition of operation, added a reference to [NETCONF]. 30. Created a change log section 31. Fixed reference to IETF XML Registry in IANA Considerations section. Chisholm & Trevino Expires January 9, 2008 [Page 35] Internet-Draft NETCONF Event Notifications July 2007 32. In section 3.3.3, deleted "This notification will only be sent if a 'stopTime' was specified when the replay subscription was created." 33. Added text to the security considerations section that says "If a subscription is created with a stopTime, the NETCONF session will return to being a normal command-response NETCONF session when the replay is completed. It is the responsibility of the NETCONF client to close off this session when it is no longer of use". 34. Update examples in section 5 to get rid of extra wrapper tag. 35. In section 2.1, replace "A NETCONF server is not required to process RPC requests on the session associated with the subscription until the notification subscription is done and may silently discard these requests." with "A NETCONF server is will not read RPC requests, by default, on the session associated with the subscription until the notification subscription is done. 36. Updated the notification definition and the replyComplete notification definition to use a substitution group. Chisholm & Trevino Expires January 9, 2008 [Page 36] Internet-Draft NETCONF Event Notifications July 2007 Authors' Addresses Sharon Chisholm Nortel 3500 Carling Ave Nepean, Ontario K2H 8E9 Canada Email: schishol@nortel.com Hector Trevino Cisco Suite 400 9155 E. Nichols Ave Englewood, CO 80112 USA Email: htrevino@cisco.com Chisholm & Trevino Expires January 9, 2008 [Page 37] Internet-Draft NETCONF Event Notifications July 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). 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. 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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. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Chisholm & Trevino Expires January 9, 2008 [Page 38]