Network Working Group S. Chisholm Internet-Draft K. Curran Expires: April 27, 2006 Nortel H. Trevino Cisco October 24, 2005 Netconf Event Messages draft-chisholm-netconf-event-01.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 April 27, 2006. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This memo defines a framework for sending asynchronous messages, or event messages 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 April 27, 2006 [Page 1] Internet-Draft Netconf Event Messages October 2005 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1 Definition of Terms . . . . . . . . . . . . . . . . . . . 4 1.2 Event Messages in Netconf . . . . . . . . . . . . . . . . 5 2. Event-Related Operations . . . . . . . . . . . . . . . . . . . 6 2.1 Subscribing to receive Events . . . . . . . . . . . . . . 6 2.1.1 create-subscription . . . . . . . . . . . . . . . . . 6 2.2 Sending Events . . . . . . . . . . . . . . . . . . . . . . 7 2.2.1 Events . . . . . . . . . . . . . . . . . . . . . . . . 7 2.3 Changing the Subscription . . . . . . . . . . . . . . . . 8 2.3.1 modify-subscription . . . . . . . . . . . . . . . . . 8 2.4 Terminating the Subscription . . . . . . . . . . . . . . . 9 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 . . . . . . . . . . . . . . . . . . . 11 3.4 User-Specified Filters . . . . . . . . . . . . . . . . . . 12 3.4.1 Named Profiles . . . . . . . . . . . . . . . . . . . . 12 3.4.2 Just-in-time Filtering . . . . . . . . . . . . . . . . 12 3.5 Event Classes . . . . . . . . . . . . . . . . . . . . . . 12 3.6 Defining Event Messages . . . . . . . . . . . . . . . . . 13 3.7 Interleaving Messages . . . . . . . . . . . . . . . . . . 13 4. XML Schema for Event Messages . . . . . . . . . . . . . . . . 15 5. Mapping to Application Protocols . . . . . . . . . . . . . . . 19 5.1 SSH . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 5.2 BEEP . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 5.2.1 One-way Messages in Beep . . . . . . . . . . . . . . . 20 5.3 SOAP . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 5.3.1 A Netconf over Soap over HTTP Example . . . . . . . . 21 6. Security Considerations . . . . . . . . . . . . . . . . . . . 24 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 25 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 26 A. Potential Event Content . . . . . . . . . . . . . . . . . . . 27 A.1 Event Identifier . . . . . . . . . . . . . . . . . . . . . 27 A.2 Resource Instance . . . . . . . . . . . . . . . . . . . . 27 A.3 Event Time . . . . . . . . . . . . . . . . . . . . . . . . 27 A.4 Perceived Severity . . . . . . . . . . . . . . . . . . . . 27 A.5 Probable Cause . . . . . . . . . . . . . . . . . . . . . . 28 A.6 Specific Problem . . . . . . . . . . . . . . . . . . . . . 28 A.7 Trend Indication . . . . . . . . . . . . . . . . . . . . . 28 A.8 Additional Alarm Text . . . . . . . . . . . . . . . . . . 28 A.9 Threshold Identifier . . . . . . . . . . . . . . . . . . . 28 A.10 Threshold Type . . . . . . . . . . . . . . . . . . . . . . 29 A.11 Observed Value . . . . . . . . . . . . . . . . . . . . . . 29 A.12 State Change Information . . . . . . . . . . . . . . . . . 29 Chisholm, et al. Expires April 27, 2006 [Page 2] Internet-Draft Netconf Event Messages October 2005 B. Configuration Event Class Messages . . . . . . . . . . . . . . 30 B.1 Types of Configuration Events . . . . . . . . . . . . . . 30 B.2 Configuration Event Content . . . . . . . . . . . . . . . 31 B.2.1 Target Datastore . . . . . . . . . . . . . . . . . . . 31 B.2.2 User Info . . . . . . . . . . . . . . . . . . . . . . 31 B.2.3 Data Source . . . . . . . . . . . . . . . . . . . . . 31 B.2.4 Operation . . . . . . . . . . . . . . . . . . . . . . 31 B.2.5 Context . . . . . . . . . . . . . . . . . . . . . . . 32 B.2.6 Entered Command . . . . . . . . . . . . . . . . . . . 32 B.2.7 New Config . . . . . . . . . . . . . . . . . . . . . . 32 B.2.8 Old Config . . . . . . . . . . . . . . . . . . . . . . 32 C. Design Alternative . . . . . . . . . . . . . . . . . . . . . . 33 C.1 Server Session Initiation . . . . . . . . . . . . . . . . 33 C.2 Event Subscription Initiation . . . . . . . . . . . . . . 33 C.2.1 Establishment . . . . . . . . . . . . . . . . . . . . 33 C.2.2 Teardown . . . . . . . . . . . . . . . . . . . . . . . 34 C.2.3 Suspend And Resume . . . . . . . . . . . . . . . . . . 34 C.2.4 Lifecycle . . . . . . . . . . . . . . . . . . . . . . 34 D. Netconf Event Messages and Syslog . . . . . . . . . . . . . . 35 D.1 Leveraging Syslog Field Definitions . . . . . . . . . . . 35 D.1.1 Field Mapping . . . . . . . . . . . . . . . . . . . . 36 D.1.2 Severity Mapping . . . . . . . . . . . . . . . . . . . 37 D.2 Syslog within NETCONF Events . . . . . . . . . . . . . . . 37 D.2.1 Motivation . . . . . . . . . . . . . . . . . . . . . . 37 D.2.2 Embedding syslog messages in a NETCONF Event . . . . . 37 D.2.3 Supported Forwarding Options . . . . . . . . . . . . . 38 Intellectual Property and Copyright Statements . . . . . . . . 40 Chisholm, et al. Expires April 27, 2006 [Page 3] Internet-Draft Netconf Event Messages October 2005 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 messages 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 April 27, 2006 [Page 4] Internet-Draft Netconf Event Messages October 2005 1.2 Event Messages 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 message, 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 messages from a Netconf server by creating a subscription to receive events. The Netconf server replies to indicate whether the subscription request was successful and, if it was successful, begins sending the event messages to the Netconf client as the events occur within the system. These event messages will continue to be sent until either the Netconf session is terminated or an explicit command to cancel the subscription is sent. The event 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 April 27, 2006 [Page 5] Internet-Draft Netconf Event Messages October 2005 2. Event-Related Operations 2.1 Subscribing to receive Events The event subscription is initiated by the Netconf client and responded to by the Netconf server. When the event subscription is created, the events of interest are specified. It is possible to create more than one event subscription on a single underlying connection. Each event subscription therefore has its own unique identifier. Content for an event 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 subscription which will send asynchronous event messages 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 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 filtered Chisholm, et al. Expires April 27, 2006 [Page 6] Internet-Draft Netconf Event Messages October 2005 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 Events Once the subscription has been set up, the Netconf server sends the events asynchronously along the connection. Messages are tagged with an event class, subscription ID, sequence number, and date and time. 2.2.1 Events Events Description: An event message is sent to the initiator of an command asynchronously when an event of interest to them has occurred. An event is a complete XML document. Parameters: Event Classes: The event class or classes associated with this event Subscription Id: A unique identifier for this event subscription Sequence Number: A sequentially increasing number to uniquely identify event messages for this subscription. Chisholm, et al. Expires April 27, 2006 [Page 7] Internet-Draft Netconf Event Messages October 2005 Data and Time: The date and time that the event was sent by the Netconf server. Positive Response: No response. Negative Response: No response. 2.2.1.1 Event Message The NETCONF Event message 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 subscription has been established, the Netconf client can initiate a request to change properties of the event subscription. This prevents loss of events that might otherwise occur during a tear down and recreation of the event subscription. This command is responded to by the Netconf server 2.3.1 modify-subscription Description: Chisholm, et al. Expires April 27, 2006 [Page 8] Internet-Draft Netconf Event Messages October 2005 Change properties of the event 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: An element is included within the if the request cannot be completed for any reason. 2.4 Terminating the Subscription Closing of the event 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 Chisholm, et al. Expires April 27, 2006 [Page 9] Internet-Draft Netconf Event Messages October 2005 the behaviour of this command. 2.4.1 cancel-subscription Description: Tear down the event subscription. Parameters: Subscription Id: A unique identifier for this event 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 April 27, 2006 [Page 10] Internet-Draft Netconf Event Messages October 2005 3. Supporting Concepts 3.1 Capabilities Exchange The ability to process and send event messages is advertised during the capability exchange between the Netconf client and server. "urn:ietf:params:xml:ns:netconf:event: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:event:1.0 4 3.2 Querying Subscription Properties This area is for further study. [Editor's Note: A read-only schema might get added, to enable the get operation to retrieve this information. Making it writable would add to the complexity of the implementation and also lead to the temptation to keep adding options and features which could lead us down a slippery slope to end up with a similar solution to what we had in SNMP, which no one could ever figure out how to use.] 3.3 RPC One-way Messages In order to support the concept that each individual event message 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. Chisholm, et al. Expires April 27, 2006 [Page 11] Internet-Draft Netconf Event Messages October 2005 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 events, this RPC will originate from the Netconf server, and not the Netconf client. 3.4 User-Specified Filters 3.4.1 Named Profiles A named profile is a filter that is created ahead of time and applied at the time an event subscription is created or modified. Note that changes to the profile after the subscription has been created alter the event messages received. 3.4.2 Just-in-time Filtering Just-in-time filtering is explicitly stated when the event subscription is created. It can only be changed using the modify subscription command. This is specified via the Filter parameter. 3.5 Event Classes Events can be broadly classified into one more event classes. The initial set of event classes is fault, information, state, audit, configuration, data, maintenance, metrics, security and heartbeat. A fault event message is generated when a fault condition (error or warning) occurs. 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). 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. Chisholm, et al. Expires April 27, 2006 [Page 12] Internet-Draft Netconf Event Messages October 2005 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. 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 Messages Event Messages 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. See 'Framework for Netconf Data Models' [Netconf-Datamodels] for more information. 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 messages 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 April 27, 2006 [Page 13] Internet-Draft Netconf Event Messages October 2005 The following sequence diagram demonstrates an example Netconf session where after basic session establishment and capability exchange, Netconf client (C), subscribes to receive events. The Netconf server (S), starts sending event messages 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 message. The Netconf server finishes sending this event message before processing the command and sending the reply. C S | | | capability exchange | --------------------------->| <-------------------------->| | | | | |-------------------------->| |<--------------------------| | | | | |<--------------------------| | | | | |<--------------------------| | | | | |-------------------------->| (buffered) | | |<--------------------------| | | |<--------------------------| Chisholm, et al. Expires April 27, 2006 [Page 14] Internet-Draft Netconf Event Messages October 2005 4. XML Schema for Event Messages 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 April 27, 2006 [Page 15] Internet-Draft Netconf Event Messages October 2005 Chisholm, et al. Expires April 27, 2006 [Page 16] Internet-Draft Netconf Event Messages October 2005 Chisholm, et al. Expires April 27, 2006 [Page 17] Internet-Draft Netconf Event Messages October 2005 The date and time that the event was sent by the netconf server. Chisholm, et al. Expires April 27, 2006 [Page 18] Internet-Draft Netconf Event Messages October 2005 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 events 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 of an XML syntax or parsing error, allowing resynchronization of the NETCONF exchange. The NETCONF over SSH session to receive an event might look like this: Chisholm, et al. Expires April 27, 2006 [Page 19] Internet-Draft Netconf Event Messages October 2005 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 April 27, 2006 [Page 20] Internet-Draft Netconf Event Messages October 2005 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 events 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 S: Content-Length: 917 Chisholm, et al. Expires April 27, 2006 [Page 21] Internet-Draft Netconf Event Messages October 2005 S: S: S: S: S: S: S: S: 123456 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 S: S: Chisholm, et al. Expires April 27, 2006 [Page 22] Internet-Draft Netconf Event Messages October 2005 S: S: S: S: S: S: S: S: S: Chisholm, et al. Expires April 27, 2006 [Page 23] Internet-Draft Netconf Event Messages October 2005 6. 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 April 27, 2006 [Page 24] Internet-Draft Netconf Event Messages October 2005 7. Acknowledgements Thanks to Gilbert Gagnon and Greg Wilbur for providing their input into this document 8. 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 Levels", RFC 2119, March 1997. [refs.RFC2223] Postel, J. and J. Reynolds, "Instructions to RFC Authors", Chisholm, et al. Expires April 27, 2006 [Page 25] Internet-Draft Netconf Event Messages October 2005 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 S9155 E. Nichols Ave Englewood, CO 80112 USA Email: htrevino@cisco.com Chisholm, et al. Expires April 27, 2006 [Page 26] Internet-Draft Netconf Event Messages October 2005 Appendix A. Potential Event Content This non-normative appendix explores possible content of event messages. 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 via different mechanisms (e.g. syslog, NETCONF). 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. Where, event generation time is a timestamp and event sysUpTime is the SNMP 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 RFC1907/RFC2578 - "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 April 27, 2006 [Page 27] Internet-Draft Netconf Event Messages October 2005 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 has set. This is analogous to the alarmVariable OBJECT-TYPE in RFC2819. Applicable event classes: fault (optional - useful for threshold crossing alarms) Chisholm, et al. Expires April 27, 2006 [Page 28] Internet-Draft Netconf Event Messages October 2005 A.10 Threshold Type This parameter is used to indicate the direction of the threshold crossing: rising, falling, or clear. Note that while compatible with RMON, this method of reporting thresholds is overloaded. Consideration should be given to be able to properly distinguish between crossing a lower threshold (falling) to be out of range and crossing an upper threshold to be back within an acceptable range (falling). Similarly, the 2 types of rising should be distinguishable. Applicable event classes: fault (optional - 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 (optional - 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 draft-ietf-entmib-state-07.txt for state attributes and values are being followed. Applicable event classes: state Chisholm, et al. Expires April 27, 2006 [Page 29] Internet-Draft Netconf Event Messages October 2005 Appendix B. Configuration Event Class Messages This non-normative appendix provides a detailed description of a configuration change event definition in support of the configuration operations, particularly those defined by the NETCONF protocol. B.1 Types of Configuration Events Configuration event messages include: o Resource Related Events o Netconf Related Events Resource Related Events are those 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 related 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 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- Chisholm, et al. Expires April 27, 2006 [Page 30] Internet-Draft Netconf Event Messages October 2005 config (merge, replace, delete, create). This event is not intended to report completely unsuccessful configuration operations. o lock-config event o unlock-config event B.2 Configuration Event Content The applicability of these fields to other event classes is for further study. B.2.1 Target Datastore Target datastore refers to the data store (startup, candidate, running) which was modified by the management operation. B.2.2 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.2.3 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 B.2.4 Operation Operation is used, for example, in the edit configuration command to indicated the specific operation that has taken place - create, Chisholm, et al. Expires April 27, 2006 [Page 31] Internet-Draft Netconf Event Messages October 2005 delete, merge, replace. B.2.5 Context The configuration sub-mode under which the command was executed. This field may be either CLI (text) or a Netconf command. [Editor's Note: how do we tell the difference?] B.2.6 Entered Command The command entered and executed on the device. This can either be CLI (text) or a Netconf command.[Editor's Note: how do we tell the difference?] B.2.7 New Config The device's configuration following the successful execution of the entered command. This can either be CLI (text) or a Netconf command.[Editor's Note: how do we tell the difference?] B.2.8 Old Config The configuration prior to the execution of the entered command. This can either be CLI (text) or a Netconf command.[Editor's Note: how do we tell the difference?] Chisholm, et al. Expires April 27, 2006 [Page 32] Internet-Draft Netconf Event Messages October 2005 Appendix C. Design Alternative C.1 Server Session Initiation Currently the NETCONF protocol requires session establishment to be initiated by the NETCONF client. With the introduction of event messages 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 where the device is pre-configured with the target destination for the management station 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. C.2 Event Subscription Initiation 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: , , used in same manner as described in doc. It may use useful to allow a client and server to re-establish a events subscription. This would be yet another capability to allow session initiation by the server. C.2.1 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 Chisholm, et al. Expires April 27, 2006 [Page 33] Internet-Draft Netconf Event Messages October 2005 information as part of its configuration. C.2.2 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 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. C.2.3 Suspend And Resume Since the purpose of the operation is to stop event message 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 message forwarding without removing the existing subscription information. Operations and > are proposed for this purpose. [Editor's Note: how would this work in the case of accidental session termination?] C.2.4 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 April 27, 2006 [Page 34] Internet-Draft Netconf Event Messages October 2005 Appendix D. Netconf Event Messages and Syslog This appendix describes the mapping between syslog message fields and NETCONF event message 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 message. D.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 April 27, 2006 [Page 35] Internet-Draft Netconf Event Messages October 2005 D.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 April 27, 2006 [Page 36] Internet-Draft Netconf Event Messages October 2005 D.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. D.2 Syslog within NETCONF Events D.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 message. The information provided in this appendix describes a mechanism to leverage syslog messages for the purpose of complementing the available Netconf event message 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. D.2.2 Embedding syslog messages in a NETCONF Event When event messages are supported, the default behaviour for a NETCONF server is to send Netconf event messages over an established event subscription. As an option, the NETCONF server may embed a syslog message in its entirety (e.g. RFC3164 - PRI, Header, and Chisholm, et al. Expires April 27, 2006 [Page 37] Internet-Draft Netconf Event Messages October 2005 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 Messages D.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) D.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 messages. 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 message, embed the syslog message in the SyslogInfo field and forward the NETCONF event messages to all subscribed destinations. Otherwise, both Netconf event and syslog messages must be included in the Event Info field. D.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 message is generated and lets the consumer of the message know what to expect. NETCONF event messages 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 Chisholm, et al. Expires April 27, 2006 [Page 38] Internet-Draft Netconf Event Messages October 2005 the SyslogInfo field or hands the syslog message to the entity responsible for processing syslog messages. D.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 messages. D.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 April 27, 2006 [Page 39] Internet-Draft Netconf Event Messages October 2005 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. 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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 (2005). 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 April 27, 2006 [Page 40] Internet-Draft Netconf Event Messages October 2005 Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Chisholm, et al. Expires April 27, 2006 [Page 41]