Network Working Group
Request for Comments: 3413
STD: 62
Obsoletes: 2573
Category: Standards Track
D. Levi
Nortel Networks
P. Meyer
Secure Computing Corporation
B. Stewart
Retired
December 2002
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Simple Network Management Protocol (SNMP) Applications

Status of this Memo

This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.

Abstract

This document describes five types of Simple Network Management Protocol (SNMP) applications which make use of an SNMP engine as described in STD 62, RFC 3411. The types of application described are Command Generators, Command Responders, Notification Originators, Notification Receivers, and Proxy Forwarders.

This document also defines Management Information Base (MIB) modules for specifying targets of management operations, for notification filtering, and for proxy forwarding. This document obsoletes RFC 2573.

Table of Contents

1 Overview
1.1 Command Generator Applications
1.2 Command Responder Applications
1.3 Notification Originator Applications
1.4 Notification Receiver Applications
1.5 Proxy Forwarder Applications
2 Management Targets
3 Elements Of Procedure
3.1 Command Generator Applications
3.2 Command Responder Applications
3.3 Notification Originator Applications
3.4 Notification Receiver Applications
3.5 Proxy Forwarder Applications
3.5.1 Request Forwarding


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3.5.1.1 Processing an Incoming Request
3.5.1.2 Processing an Incoming Response
3.5.1.3 Processing an Incoming Internal-Class PDU
3.5.2 Notification Forwarding
4 The Structure of the MIB Modules
4.1 The Management Target MIB Module
4.1.1 Tag Lists
4.1.2 Definitions
4.2 The Notification MIB Module
4.2.1 Definitions
4.3 The Proxy MIB Module
4.3.1 Definitions

   5       Identification of Management Targets in
Notification Originators
6 Notification Filtering
   7       Management Target Translation in
Proxy Forwarder Applications
   7.1     Management Target Translation for
Request Forwarding
   7.2     Management Target Translation for
Notification Forwarding
8 Intellectual Property
9 Acknowledgments
10 Security Considerations
11 References
A. Trap Configuration Example
Editors' Addresses
Full Copyright Statement

1 Overview

This document describes five types of SNMP applications:

   - Applications which initiate SNMP Read-Class, and/or Write-Class
     requests, called 'command generators.'

   - Applications which respond to SNMP Read-Class, and/or Write-Class
     requests, called 'command responders.'

   - Applications which generate SNMP Notification-Class PDUs, called
     'notification originators.'

   - Applications which receive SNMP Notification-Class PDUs, called
     'notification receivers.'

   - Applications which forward SNMP messages, called 'proxy
     forwarders.'


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Note that there are no restrictions on which types of applications may be associated with a particular SNMP engine. For example, a single SNMP engine may, in fact, be associated with both command generator and command responder applications.

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].

1.1 Command Generator Applications

A command generator application initiates SNMP Read-Class and/or Write-Class requests, and processes responses to requests which it generated.

1.2 Command Responder Applications

A command responder application receives SNMP Read-Class and/or Write-Class requests destined for the local system as indicated by the fact that the contextEngineID in the received request is equal to that of the local engine through which the request was received. The command responder application will perform the appropriate protocol operation, using access control, and will generate a response message to be sent to the request's originator.

1.3 Notification Originator Applications

A notification originator application conceptually monitors a system for particular events or conditions, and generates Notification-Class messages based on these events or conditions. A notification originator must have a mechanism for determining where to send messages, and what SNMP version and security parameters to use when sending messages. A mechanism and MIB module for this purpose is provided in this document. Note that Notification-Class PDUs generated by a notification originator may be either Confirmed-Class or Unconfirmed-Class PDU types.

1.4 Notification Receiver Applications

A notification receiver application listens for notification messages, and generates response messages when a message containing a Confirmed-Class PDU is received.


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1.5 Proxy Forwarder Applications

A proxy forwarder application forwards SNMP messages. Note that implementation of a proxy forwarder application is optional. The sections describing proxy (3.5, 4.3, and 7) may be skipped for implementations that do not include a proxy forwarder application.

The term "proxy" has historically been used very loosely, with multiple different meanings. These different meanings include (among others):

(1) the forwarding of SNMP requests to other SNMP entities without regard for what managed object types are being accessed; for example, in order to forward an SNMP request from one transport domain to another, or to translate SNMP requests of one version into SNMP requests of another version;

(2) the translation of SNMP requests into operations of some non-SNMP management protocol; and

(3) support for aggregated managed objects where the value of one managed object instance depends upon the values of multiple other (remote) items of management information.

Each of these scenarios can be advantageous; for example, support for aggregation of management information can significantly reduce the bandwidth requirements of large-scale management activities.

However, using a single term to cover multiple different scenarios causes confusion.

To avoid such confusion, this document uses the term "proxy" with a much more tightly defined meaning. The term "proxy" is used in this document to refer to a proxy forwarder application which forwards either SNMP messages without regard for what managed objects are contained within those messages. This definition is most closely related to the first definition above. Note, however, that in the SNMP architecture [RFC3411], a proxy forwarder is actually an application, and need not be associated with what is traditionally thought of as an SNMP agent.

Specifically, the distinction between a traditional SNMP agent and a proxy forwarder application is simple:


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   - a proxy forwarder application forwards SNMP messages to other SNMP
     engines according to the context, and irrespective of the specific
     managed object types being accessed, and forwards the response to
     such previously forwarded messages back to the SNMP engine from
     which the original message was received;

   - in contrast, the command responder application that is part of what
     is traditionally thought of as an SNMP agent, and which processes
     SNMP requests according to the (names of the) individual managed
     object types and instances being accessed, is NOT a proxy forwarder
     application from the perspective of this document.

Thus, when a proxy forwarder application forwards a request or notification for a particular contextEngineID / contextName pair, not only is the information on how to forward the request specifically associated with that context, but the proxy forwarder application has no need of a detailed definition of a MIB view (since the proxy forwarder application forwards the request irrespective of the managed object types).

In contrast, a command responder application must have the detailed definition of the MIB view, and even if it needs to issue requests to other entities, via SNMP or otherwise, that need is dependent on the individual managed object instances being accessed (i.e., not only on the context).

Note that it is a design goal of a proxy forwarder application to act as an intermediary between the endpoints of a transaction. In particular, when forwarding Confirmed Notification-Class messages, the associated response is forwarded when it is received from the target to which the Notification-Class message was forwarded, rather than generating a response immediately when the Notification-Class message is received.

2 Management Targets

Some types of applications (notification generators and proxy forwarders in particular) require a mechanism for determining where and how to send generated messages. This document provides a mechanism and MIB module for this purpose. The set of information that describes where and how to send a message is called a 'Management Target', and consists of two kinds of information:

   - Destination information, consisting of a transport domain and a
     transport address.  This is also termed a transport endpoint.

   - SNMP parameters, consisting of message processing model, security
     model, security level, and security name information.


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The SNMP-TARGET-MIB module described later in this document contains one table for each of these types of information. There can be a many-to-many relationship in the MIB between these two types of information. That is, there may be multiple transport endpoints associated with a particular set of SNMP parameters, or a particular transport endpoint may be associated with several sets of SNMP parameters.

3 Elements Of Procedure

The following sections describe the procedures followed by each type of application when generating messages for transmission or when processing received messages. Applications communicate with the Dispatcher using the abstract service interfaces defined in [RFC3411].

3.1 Command Generator Applications

A command generator initiates an SNMP request by calling the Dispatcher using the following abstract service interface:

      statusInformation =              -- sendPduHandle if success
                                       -- errorIndication if failure
        sendPdu(
        IN   transportDomain           -- transport domain to be used
        IN   transportAddress          -- destination network address
        IN   messageProcessingModel    -- typically, SNMP version
        IN   securityModel             -- Security Model to use
        IN   securityName              -- on behalf of this principal
        IN   securityLevel             -- Level of Security requested
        IN   contextEngineID           -- data from/at this entity
        IN   contextName               -- data from/in this context
        IN   pduVersion                -- the version of the PDU
        IN   PDU                       -- SNMP Protocol Data Unit
        IN   expectResponse            -- TRUE or FALSE
             )

Where:

   - The transportDomain is that of the destination of the message.

   - The transportAddress is that of the destination of the message.

   - The messageProcessingModel indicates which Message Processing Model
     the application wishes to use.

   - The securityModel is the security model that the application wishes
     to use.


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   - The securityName is the security model independent name for the
     principal on whose behalf the application wishes the message to be
     generated.

   - The securityLevel is the security level that the application wishes
     to use.

   - The contextEngineID specifies the location of the management
     information it is requesting.  Note that unless the request is
     being sent to a proxy, this value will usually be equal to the
     snmpEngineID value of the engine to which the request is being
     sent.

   - The contextName specifies the local context name for the management
     information it is requesting.

   - The pduVersion indicates the version of the PDU to be sent.

   - The PDU is a value constructed by the command generator containing
     the management operation that the command generator wishes to
     perform.

   - The expectResponse argument indicates that a response is expected.

The result of the sendPdu interface indicates whether the PDU was successfully sent. If it was successfully sent, the returned value will be a sendPduHandle. The command generator should store the sendPduHandle so that it can correlate a response to the original request.

The Dispatcher is responsible for delivering the response to a particular request to the correct command generator application. The abstract service interface used is:

      processResponsePdu(              -- process Response PDU
        IN   messageProcessingModel    -- typically, SNMP version
        IN   securityModel             -- Security Model in use
        IN   securityName              -- on behalf of this principal
        IN   securityLevel             -- Level of Security
        IN   contextEngineID           -- data from/at this SNMP entity
        IN   contextName               -- data from/in this context
        IN   pduVersion                -- the version of the PDU
        IN   PDU                       -- SNMP Protocol Data Unit
        IN   statusInformation         -- success or errorIndication
        IN   sendPduHandle             -- handle from sendPdu
             )


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Where:

   - The messageProcessingModel is the value from the received response.

   - The securityModel is the value from the received response.

   - The securityName is the value from the received response.

   - The securityLevel is the value from the received response.

   - The contextEngineID is the value from the received response.

   - The contextName is the value from the received response.

   - The pduVersion indicates the version of the PDU in the received
     response.

   - The PDU is the value from the received response.

   - The statusInformation indicates success or failure in receiving the
     response.

   - The sendPduHandle is the value returned by the sendPdu call which
     generated the original request to which this is a response.

The procedure when a command generator receives a message is as follows:

(1) If the received values of messageProcessingModel, securityModel, securityName, contextEngineID, contextName, and pduVersion are not all equal to the values used in the original request, the response is discarded.

(2) The operation type, request-id, error-status, error-index, and variable-bindings are extracted from the PDU and saved. If the request-id is not equal to the value used in the original request, the response is discarded.

(3) At this point, it is up to the application to take an appropriate action. The specific action is implementation dependent. If the statusInformation indicates that the request failed, an appropriate action might be to attempt to transmit the request again, or to notify the person operating the application that a failure occurred.


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3.2 Command Responder Applications

Before a command responder application can process messages, it must first associate itself with an SNMP engine. The abstract service interface used for this purpose is:

      statusInformation =       -- success or errorIndication
       registerContextEngineID(
       IN   contextEngineID     -- take responsibility for this one
       IN   pduType             -- the pduType(s) to be registered
            )

Where:

   - The statusInformation indicates success or failure of the
     registration attempt.

   - The contextEngineID is equal to the snmpEngineID of the SNMP engine
     with which the command responder is registering.

   - The pduType indicates a Read-Class and/or Write-Class PDU.

Note that if another command responder application is already registered with an SNMP engine, any further attempts to register with the same contextEngineID and pduType will be denied. This implies that separate command responder applications could register separately for the various pdu types. However, in practice this is undesirable, and only a single command responder application should be registered with an SNMP engine at any given time.

A command responder application can disassociate with an SNMP engine using the following abstract service interface:

unregisterContextEngineID(

        IN   contextEngineID     -- give up responsibility for this one
        IN   pduType             -- the pduType(s) to be unregistered
             )

Where:

   - The contextEngineID is equal to the snmpEngineID of the SNMP engine
     with which the command responder is cancelling the registration.

   - The pduType indicates a Read-Class and/or Write-Class PDU.


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Once the command responder has registered with the SNMP engine, it waits to receive SNMP messages. The abstract service interface used for receiving messages is:

   processPdu(                     -- process Request/Notification PDU
     IN   messageProcessingModel   -- typically, SNMP version
     IN   securityModel            -- Security Model in use
     IN   securityName             -- on behalf of this principal
     IN   securityLevel            -- Level of Security
     IN   contextEngineID          -- data from/at this SNMP entity
     IN   contextName              -- data from/in this context
     IN   pduVersion               -- the version of the PDU
     IN   PDU                      -- SNMP Protocol Data Unit
     IN   maxSizeResponseScopedPDU -- maximum size of the Response PDU
     IN   stateReference           -- reference to state information
          )                        -- needed when sending a response

Where:

   - The messageProcessingModel indicates which Message Processing Model
     received and processed the message.

   - The securityModel is the value from the received message.

   - The securityName is the value from the received message.

   - The securityLevel is the value from the received message.

   - The contextEngineID is the value from the received message.

   - The contextName is the value from the received message.

   - The pduVersion indicates the version of the PDU in the received
     message.

   - The PDU is the value from the received message.

   - The maxSizeResponseScopedPDU is the maximum allowable size of a
     ScopedPDU containing a Response PDU (based on the maximum message
     size that the originator of the message can accept).

   - The stateReference is a value which references cached information
     about each received request message.  This value must be returned
     to the Dispatcher in order to generate a response.


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The procedure when a message is received is as follows:

(1) The operation type is determined from the ASN.1 tag value associated with the PDU parameter. The operation type should always be one of the types previously registered by the application.

(2) The request-id is extracted from the PDU and saved.

(3) Any PDU type specific parameters are extracted from the PDU and saved (for example, if the PDU type is an SNMPv2 GetBulk PDU, the non-repeaters and max-repetitions values are extracted).

(4) The variable-bindings are extracted from the PDU and saved.

(5) The management operation represented by the PDU type is performed with respect to the relevant MIB view within the context named by the contextName (for an SNMPv2 PDU type, the operation is performed according to the procedures set forth in [RFC1905]). The relevant MIB view is determined by the securityLevel, securityModel, contextName, securityName, and the class of the PDU type. To determine whether a particular object instance is within the relevant MIB view, the following abstract service interface is called:

          statusInformation =      -- success or errorIndication
            isAccessAllowed(
            IN   securityModel     -- Security Model in use
            IN   securityName      -- principal who wants to access
            IN   securityLevel     -- Level of Security
            IN   viewType          -- read, write, or notify view
            IN   contextName       -- context containing variableName
            IN   variableName      -- OID for the managed object
                 )

Where:

       - The securityModel is the value from the received message.

       - The securityName is the value from the received message.

       - The securityLevel is the value from the received message.

       - The viewType indicates whether the PDU type is a Read-Class or
         Write-Class operation.

       - The contextName is the value from the received message.


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       - The variableName is the object instance of the variable for
         which access rights are to be checked.

Normally, the result of the management operation will be a new PDU value, and processing will continue in step (6) below. However, at any time during the processing of the management operation:

       - If the isAccessAllowed ASI returns a noSuchView, noAccessEntry,
         or noGroupName error, processing of the management operation is
         halted, a PDU value is constructed using the values from the
         originally received PDU, but replacing the error-status with an
         authorizationError code, and error-index value of 0, and
         control is passed to step (6) below.

       - If the isAccessAllowed ASI returns an otherError, processing of
         the management operation is halted, a different PDU value is
         constructed using the values from the originally received PDU,
         but replacing the error-status with a genError code and the
         error-index with the index of the failed variable binding, and
         control is passed to step (6) below.

       - If the isAccessAllowed ASI returns a noSuchContext error,
         processing of the management operation is halted, no result PDU
         is generated, the snmpUnknownContexts counter is incremented,
         and control is passed to step (6) below for generation of a
         report message.

       - If the context named by the contextName parameter is
         unavailable, processing of the management operation is halted,
         no result PDU is generated, the snmpUnavailableContexts counter
         is incremented, and control is passed to step (6) below for
         generation of a report message.

(6) The Dispatcher is called to generate a response or report message. The abstract service interface is:


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returnResponsePdu(
  IN   messageProcessingModel   -- typically, SNMP version
  IN   securityModel            -- Security Model in use
  IN   securityName             -- on behalf of this principal
  IN   securityLevel            -- same as on incoming request
  IN   contextEngineID          -- data from/at this SNMP entity
  IN   contextName              -- data from/in this context
  IN   pduVersion               -- the version of the PDU
  IN   PDU                      -- SNMP Protocol Data Unit
  IN   maxSizeResponseScopedPDU -- maximum size of the Response PDU
  IN   stateReference           -- reference to state information
                                -- as presented with the request
  IN   statusInformation        -- success or errorIndication
       )                        -- error counter OID/value if error

Where:

       - The messageProcessingModel is the value from the processPdu
         call.

       - The securityModel is the value from the processPdu call.

       - The securityName is the value from the processPdu call.

       - The securityLevel is the value from the processPdu call.

       - The contextEngineID is the value from the processPdu call.

       - The contextName is the value from the processPdu call.

       - The pduVersion indicates the version of the PDU to be returned.
         If no result PDU was generated, the pduVersion is an undefined
         value.

       - The PDU is the result generated in step (5) above.  If no
         result PDU was generated, the PDU is an undefined value.

       - The maxSizeResponseScopedPDU is a local value indicating the
         maximum size of a ScopedPDU that the application can accept.

       - The stateReference is the value from the processPdu call.

       - The statusInformation either contains an indication that no
         error occurred and that a response should be generated, or
         contains an indication that an error occurred along with the
         OID and counter value of the appropriate error counter object.


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Note that a command responder application should always call the returnResponsePdu abstract service interface, even in the event of an error such as a resource allocation error. In the event of such an error, the PDU value passed to returnResponsePdu should contain appropriate values for errorStatus and errorIndex.

Note that the text above describes situations where the
snmpUnknownContexts counter is incremented, and where the snmpUnavailableContexts counter is incremented. The difference between these is that the snmpUnknownContexts counter is incremented when a request is received for a context which is unknown to the SNMP entity. The snmpUnavailableContexts counter is incremented when a request is received for a context which is known to the SNMP entity, but is currently unavailable. Determining when a context is unavailable is implementation specific, and some implementations may never encounter this situation, and so may never increment the snmpUnavailableContexts counter.

3.3 Notification Originator Applications

A notification originator application generates SNMP messages containing Notification-Class PDUs (for example, SNMPv2-Trap PDUs or Inform PDUs). There is no requirement as to what specific types of Notification-Class PDUs a particular implementation must be capable of generating.

Notification originator applications require a mechanism for identifying the management targets to which notifications should be sent. The particular mechanism used is implementation dependent. However, if an implementation makes the configuration of management targets SNMP manageable, it MUST use the SNMP-TARGET-MIB module described in this document.

When a notification originator wishes to generate a notification, it must first determine in which context the information to be conveyed in the notification exists, i.e., it must determine the
contextEngineID and contextName. It must then determine the set of management targets to which the notification should be sent. The application must also determine, for each management target, what specific PDU type the notification message should contain, and if it is to contain a Confirmed-Class PDU, the number of retries and retransmission algorithm.


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The mechanism by which a notification originator determines this information is implementation dependent. Once the application has determined this information, the following procedure is performed for each management target:

(1) Any appropriate filtering mechanisms are applied to determine whether the notification should be sent to the management target. If such filtering mechanisms determine that the notification should not be sent, processing continues with the next management target. Otherwise,

(2) The appropriate set of variable-bindings is retrieved from local MIB instrumentation within the relevant MIB view. The relevant MIB view is determined by the securityLevel, securityModel, contextName, and securityName of the management target. To determine whether a particular object instance is within the relevant MIB view, the isAccessAllowed abstract service interface is used, in the same manner as described in the preceding section, except that the viewType indicates a Notification-Class operation. If the statusInformation returned by isAccessAllowed does not indicate accessAllowed, the notification is not sent to the management target.

(3) The NOTIFICATION-TYPE OBJECT IDENTIFIER of the notification (this is the value of the element of the variable bindings whose name is snmpTrapOID.0, i.e., the second variable binding) is checked using the isAccessAllowed abstract service interface, using the same parameters used in the preceding step. If the
statusInformation returned by isAccessAllowed does not indicate accessAllowed, the notification is not sent to the management target.

(4) A PDU is constructed using a locally unique request-id value, a PDU type as determined by the implementation, an error-status and error-index value of 0, and the variable-bindings supplied previously in step (2).

(5) If the notification contains an Unconfirmed-Class PDU, the Dispatcher is called using the following abstract service interface:


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       statusInformation =              -- sendPduHandle if success
                                        -- errorIndication if failure
         sendPdu(
         IN   transportDomain           -- transport domain to be used
         IN   transportAddress          -- destination network address
         IN   messageProcessingModel    -- typically, SNMP version
         IN   securityModel             -- Security Model to use
         IN   securityName              -- on behalf of this principal
         IN   securityLevel             -- Level of Security requested
         IN   contextEngineID           -- data from/at this entity
         IN   contextName               -- data from/in this context
         IN   pduVersion                -- the version of the PDU
         IN   PDU                       -- SNMP Protocol Data Unit
         IN   expectResponse            -- TRUE or FALSE
              )

Where:

       - The transportDomain is that of the management target.

       - The transportAddress is that of the management target.

       - The messageProcessingModel is that of the management target.

       - The securityModel is that of the management target.

       - The securityName is that of the management target.

       - The securityLevel is that of the management target.

       - The contextEngineID is the value originally determined for the
         notification.

       - The contextName is the value originally determined for the
         notification.

       - The pduVersion is the version of the PDU to be sent.

       - The PDU is the value constructed in step (4) above.

       - The expectResponse argument indicates that no response is
         expected.

Otherwise,


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(6) If the notification contains a Confirmed-Class PDU, then:

a) The Dispatcher is called using the sendPdu abstract service interface as described in step (5) above, except that the expectResponse argument indicates that a response is expected.

b) The application caches information about the management target.

c) If a response is received within an appropriate time interval from the transport endpoint of the management target, the notification is considered acknowledged and the cached information is deleted. Otherwise,

d) If a response is not received within an appropriate time period, or if a report indication is received, information about the management target is retrieved from the cache, and steps a) through d) are repeated. The number of times these steps are repeated is equal to the previously determined retry count. If this retry count is exceeded, the acknowledgement of the notification is considered to have failed, and processing of the notification for this management target is halted. Note that some report indications might be considered a failure. Such report indications should be interpreted to mean that the acknowledgement of the notification has failed, and that steps a) through d) need not be repeated.

Responses to Confirmed-Class PDU notifications will be received via the processResponsePdu abstract service interface.

To summarize, the steps that a notification originator follows when determining where to send a notification are:

   - Determine the targets to which the notification should be sent.

   - Apply any required filtering to the list of targets.

   - Determine which targets are authorized to receive the notification.

3.4 Notification Receiver Applications

Notification receiver applications receive SNMP Notification messages from the Dispatcher. Before any messages can be received, the notification receiver must register with the Dispatcher using the registerContextEngineID abstract service interface. The parameters used are:


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   - The contextEngineID is an undefined 'wildcard' value.
     Notifications are delivered to a registered notification receiver
     regardless of the contextEngineID contained in the notification
     message.

   - The pduType indicates the type of notifications that the
     application wishes to receive (for example, SNMPv2-Trap PDUs or
     Inform PDUs).

Once the notification receiver has registered with the Dispatcher, messages are received using the processPdu abstract service interface. Parameters are:

   - The messageProcessingModel indicates which Message Processing Model
     received and processed the message.

   - The securityModel is the value from the received message.

   - The securityName is the value from the received message.

   - The securityLevel is the value from the received message.

   - The contextEngineID is the value from the received message.

   - The contextName is the value from the received message.

   - The pduVersion indicates the version of the PDU in the received
     message.

   - The PDU is the value from the received message.

   - The maxSizeResponseScopedPDU is the maximum allowable size of a
     ScopedPDU containing a Response PDU (based on the maximum message
     size that the originator of the message can accept).

   - If the message contains an Unconfirmed-Class PDU, the
     stateReference is undefined and unused.  Otherwise, the
     stateReference is a value which references cached information about
     the notification.  This value must be returned to the Dispatcher in
     order to generate a response.

When an Unconfirmed-Class PDU is delivered to a notification receiver application, it first extracts the SNMP operation type, request-id, error-status, error-index, and variable-bindings from the PDU. After this, processing depends on the particular implementation.


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When a Confirmed-Class PDU is received, the notification receiver application follows the following procedure:

(1) The PDU type, request-id, error-status, error-index, and variable-bindings are extracted from the PDU.

(2) A Response-Class PDU is constructed using the extracted request-id and variable-bindings, and with error-status and error-index both set to 0.

(3) The Dispatcher is called to generate a response message using the returnResponsePdu abstract service interface. Parameters are:

       - The messageProcessingModel is the value from the processPdu
         call.

       - The securityModel is the value from the processPdu call.

       - The securityName is the value from the processPdu call.

       - The securityLevel is the value from the processPdu call.

       - The contextEngineID is the value from the processPdu call.

       - The contextName is the value from the processPdu call.

       - The pduVersion indicates the version of the PDU to be returned.

       - The PDU is the result generated in step (2) above.

       - The maxSizeResponseScopedPDU is a local value indicating the
         maximum size of a ScopedPDU that the application can accept.

       - The stateReference is the value from the processPdu call.

       - The statusInformation indicates that no error occurred and that
         a response should be generated.

(4) After this, processing depends on the particular implementation.

3.5 Proxy Forwarder Applications

A proxy forwarder application deals with forwarding SNMP messages. There are four basic types of messages which a proxy forwarder application may need to forward. These are grouped according to the class of PDU type contained in a message. The four basic types of messages are:


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   - Those containing Read-Class or Write-Class PDU types (for example,
     Get, GetNext, GetBulk, and Set PDU types).  These deal with
     requesting or modifying information located within a particular
     context.

   - Those containing Notification-Class PDU types (for example,
     SNMPv2-Trap and Inform PDU types).  These deal with notifications
     concerning information located within a particular context.

   - Those containing a Response-Class PDU type.  Forwarding of
     Response-Class PDUs always occurs as a result of receiving a
     response to a previously forwarded message.

   - Those containing Internal-Class PDU types (for example, a Report
     PDU).  Forwarding of Internal-Class PDU types always occurs as a
     result of receiving an Internal-Class PDU in response to a
     previously forwarded message.

For the first type, the proxy forwarder's role is to deliver a request for management information to an SNMP engine which is "closer" or "downstream in the path" to the SNMP engine which has access to that information, and to deliver the response containing the information back to the SNMP engine from which the request was received. The context information in a request is used to determine which SNMP engine has access to the requested information, and this is used to determine where and how to forward the request.

For the second type, the proxy forwarder's role is to determine which SNMP engines should receive notifications about management information from a particular location. The context information in a notification message determines the location to which the information contained in the notification applies. This is used to determine which SNMP engines should receive notification about this information.

For the third type, the proxy forwarder's role is to determine which previously forwarded request or notification (if any) the response matches, and to forward the response back to the initiator of the request or notification.

For the fourth type, the proxy forwarder's role is to determine which previously forwarded request or notification (if any) the Internal- Class PDU matches, and to forward the Internal-Class PDU back to the initiator of the request or notification.


Page 21

When forwarding messages, a proxy forwarder application must perform a translation of incoming management target information into outgoing management target information. How this translation is performed is implementation specific. In many cases, this will be driven by a preconfigured translation table. If a proxy forwarder application makes the contents of this table SNMP manageable, it MUST use the SNMP-PROXY-MIB module defined in this document.

3.5.1 Request Forwarding

There are two phases for request forwarding. First, the incoming request needs to be passed through the proxy application. Then, the resulting response needs to be passed back. These phases are described in the following two sections.

3.5.1.1 Processing an Incoming Request

A proxy forwarder application that wishes to forward request messages must first register with the Dispatcher using the
registerContextEngineID abstract service interface. The proxy forwarder must register each contextEngineID for which it wishes to forward messages, as well as for each pduType. Note that as the configuration of a proxy forwarder is changed, the particular contextEngineID values for which it is forwarding may change. The proxy forwarder should call the registerContextEngineID and unregisterContextEngineID abstract service interfaces as needed to reflect its current configuration.

A proxy forwarder application should never attempt to register a value of contextEngineID which is equal to the snmpEngineID of the SNMP engine to which the proxy forwarder is associated.

Once the proxy forwarder has registered for the appropriate contextEngineID values, it can start processing messages. The following procedure is used:

(1) A message is received using the processPdu abstract service interface. The incoming management target information received from the processPdu interface is translated into outgoing management target information. Note that this translation may vary for different values of contextEngineID and/or contextName. The translation should result in a single management target.

(2) If appropriate outgoing management target information cannot be found, the proxy forwarder increments the snmpProxyDrops counter [RFC1907], and then calls the Dispatcher using the
returnResponsePdu abstract service interface. Parameters are:


Page 22

       - The messageProcessingModel is the value from the processPdu
         call.

       - The securityModel is the value from the processPdu call.

       - The securityName is the value from the processPdu call.

       - The securityLevel is the value from the processPdu call.

       - The contextEngineID is the value from the processPdu call.

       - The contextName is the value from the processPdu call.

       - The pduVersion is the value from the processPdu call.

       - The PDU is an undefined value.

       - The maxSizeResponseScopedPDU is a local value indicating the
         maximum size of a ScopedPDU that the application can accept.

       - The stateReference is the value from the processPdu call.

       - The statusInformation indicates that an error occurred and
         includes the OID and value of the snmpProxyDrops object.

Processing of the message stops at this point. Otherwise,

(3) A new PDU is constructed. A unique value of request-id should be used in the new PDU (this value will enable a subsequent response message to be correlated with this request). The remainder of the new PDU is identical to the received PDU, unless the incoming SNMP version and the outgoing SNMP version support different PDU versions, in which case the proxy forwarder may need to perform a translation on the PDU. (A method for performing such a translation is described in [RFC2576].)

(4) The proxy forwarder calls the Dispatcher to generate the forwarded message, using the sendPdu abstract service interface. The parameters are:

       - The transportDomain is that of the outgoing management target.

       - The transportAddress is that of the outgoing management target.

       - The messageProcessingModel is that of the outgoing management
         target.

       - The securityModel is that of the outgoing management target.


Page 23

       - The securityName is that of the outgoing management target.

       - The securityLevel is that of the outgoing management target.

       - The contextEngineID is the value from the processPdu call.

       - The contextName is the value from the processPdu call.

       - The pduVersion is the version of the PDU to be sent.

       - The PDU is the value constructed in step (3) above.

       - The expectResponse argument indicates that a response is
         expected.  If the sendPdu call is unsuccessful, the proxy
         forwarder performs the steps described in (2) above.
         Otherwise:

(5) The proxy forwarder caches the following information in order to match an incoming response to the forwarded request:

       - The sendPduHandle returned from the call to sendPdu,

       - The request-id from the received PDU.

       - The contextEngineID,

       - The contextName,

       - The stateReference,

       - The incoming management target information,

       - The outgoing management information,

       - Any other information needed to match an incoming response to
         the forwarded request.

If this information cannot be cached (possibly due to a lack of resources), the proxy forwarder performs the steps described in (2) above. Otherwise:

(6) Processing of the request stops until a response to the forwarded request is received, or until an appropriate time interval has expired. If this time interval expires before a response has been received, the cached information about this request is removed.


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3.5.1.2 Processing an Incoming Response

A proxy forwarder follows the following procedure when an incoming response is received:

(1) The incoming response is received using the processResponsePdu interface. The proxy forwarder uses the received parameters to locate an entry in its cache of pending forwarded requests. This is done by matching the received parameters with the cached values of sendPduHandle, contextEngineID, contextName, outgoing management target information, and the request-id contained in the received PDU (the proxy forwarder must extract the request-id for this purpose). If an appropriate cache entry cannot be found, processing of the response is halted. Otherwise:

(2) The cache information is extracted, and removed from the cache.

(3) A new Response-Class PDU is constructed, using the request-id value from the original forwarded request (as extracted from the cache). All other values are identical to those in the received Response-Class PDU, unless the incoming SNMP version and the outgoing SNMP version support different PDU versions, in which case the proxy forwarder may need to perform a translation on the PDU. (A method for performing such a translation is described in [RFC2576].)

(4) The proxy forwarder calls the Dispatcher using the
returnResponsePdu abstract service interface. Parameters are:

       - The messageProcessingModel indicates the Message Processing
         Model by which the original incoming message was processed.

       - The securityModel is that of the original incoming management
         target extracted from the cache.

       - The securityName is that of the original incoming management
         target extracted from the cache.

       - The securityLevel is that of the original incoming management
         target extracted from the cache.

       - The contextEngineID is the value extracted from the cache.

       - The contextName is the value extracted from the cache.

       - The pduVersion indicates the version of the PDU to be returned.

       - The PDU is the (possibly translated) Response PDU.


Page 25

       - The maxSizeResponseScopedPDU is a local value indicating the
         maximum size of a ScopedPDU that the application can accept.

       - The stateReference is the value extracted from the cache.

       - The statusInformation indicates that no error occurred and that
         a Response PDU message should be generated.

3.5.1.3 Processing an Incoming Internal-Class PDU

A proxy forwarder follows the following procedure when an incoming Internal-Class PDU is received:

(1) The incoming Internal-Class PDU is received using the processResponsePdu interface. The proxy forwarder uses the received parameters to locate an entry in its cache of pending forwarded requests. This is done by matching the received parameters with the cached values of sendPduHandle. If an appropriate cache entry cannot be found, processing of the Internal-Class PDU is halted. Otherwise:

(2) The cache information is extracted, and removed from the cache.

(3) If the original incoming management target information indicates an SNMP version which does not support Report PDUs, processing of the Internal-Class PDU is halted.

(4) The proxy forwarder calls the Dispatcher using the
returnResponsePdu abstract service interface. Parameters are:

       - The messageProcessingModel indicates the Message Processing
         Model by which the original incoming message was processed.

       - The securityModel is that of the original incoming management
         target extracted from the cache.

       - The securityName is that of the original incoming management
         target extracted from the cache.

       - The securityLevel is that of the original incoming management
         target extracted from the cache.

       - The contextEngineID is the value extracted from the cache.

       - The contextName is the value extracted from the cache.

       - The pduVersion indicates the version of the PDU to be returned.


Page 26

       - The PDU is unused.

       - The maxSizeResponseScopedPDU is a local value indicating the
         maximum size of a ScopedPDU that the application can accept.

       - The stateReference is the value extracted from the cache.

       - The statusInformation contains values specific to the
         Internal-Class PDU type (for example, for a Report PDU, the
         statusInformation contains the contextEngineID, contextName,
         counter OID, and counter value received in the incoming Report
         PDU).

3.5.2 Notification Forwarding

A proxy forwarder receives notifications in the same manner as a notification receiver application, using the processPdu abstract service interface. The following procedure is used when a notification is received:

(1) The incoming management target information received from the processPdu interface is translated into outgoing management target information. Note that this translation may vary for different values of contextEngineID and/or contextName. The translation may result in multiple management targets.

(2) If appropriate outgoing management target information cannot be found and the notification was an Unconfirmed-Class PDU, processing of the notification is halted. If appropriate outgoing management target information cannot be found and the notification was a Confirmed-Class PDU, the proxy forwarder increments the snmpProxyDrops object, and calls the Dispatcher using the returnResponsePdu abstract service interface. The parameters are:

       - The messageProcessingModel is the value from the processPdu
         call.

       - The securityModel is the value from the processPdu call.

       - The securityName is the value from the processPdu call.

       - The securityLevel is the value from the processPdu call.

       - The contextEngineID is the value from the processPdu call.

       - The contextName is the value from the processPdu call.


Page 27

       - The pduVersion is the value from the processPdu call.

       - The PDU is an undefined and unused value.

       - The maxSizeResponseScopedPDU is a local value indicating the
         maximum size of a ScopedPDU that the application can accept.

       - The stateReference is the value from the processPdu call.

       - The statusInformation indicates that an error occurred and that
         a Report message should be generated.

Processing of the message stops at this point. Otherwise,

(3) The proxy forwarder generates a notification using the procedures described in the preceding section on Notification Originators, with the following exceptions:

       - The contextEngineID and contextName values from the original
         received notification are used.

       - The outgoing management targets previously determined are used.

       - No filtering mechanisms are applied.

       - The variable-bindings from the original received notification
         are used, rather than retrieving variable-bindings from local
         MIB instrumentation.  In particular, no access-control is
         applied to these variable-bindings, nor to the value of the
         variable-binding containing snmpTrapOID.0.

       - If the original notification contains a Confirmed-Class PDU,
         then any outgoing management targets for which the outgoing
         SNMP version does not support any PDU types that are both
         Notification-Class and Confirmed-Class PDUs will not be used
         when generating the forwarded notifications.

       - If, for any of the outgoing management targets, the incoming
         SNMP version and the outgoing SNMP version support different
         PDU versions, the proxy forwarder may need to perform a
         translation on the PDU.  (A method for performing such a
         translation is described in [RFC2576].)

(4) If the original received notification contains an
Unconfirmed-Class PDU, processing of the notification is now completed. Otherwise, the original received notification must contain Confirmed-Class PDU, and processing continues.


Page 28

(5) If the forwarded notifications included any Confirmed-Class PDUs, processing continues when the procedures described in the section for Notification Originators determine that either:

       - None of the generated notifications containing Confirmed-Class
         PDUs have been successfully acknowledged within the longest of
         the time intervals, in which case processing of the original
         notification is halted, or,

       - At least one of the generated notifications containing
         Confirmed-Class PDUs is successfully acknowledged, in which
         case a response to the original received notification
         containing an Confirmed-Class PDU is generated as described in
         the following steps.

(6) A Response-Class PDU is constructed, using the values of request-id and variable-bindings from the original received Notification-Class PDU, and error-status and error-index values of 0.

(7) The Dispatcher is called using the returnResponsePdu abstract service interface. Parameters are:

       - The messageProcessingModel is the value from the processPdu
         call.

       - The securityModel is the value from the processPdu call.

       - The securityName is the value from the processPdu call.

       - The securityLevel is the value from the processPdu call.

       - The contextEngineID is the value from the processPdu call.

       - The contextName is the value from the processPdu call.

       - The pduVersion indicates the version of the PDU constructed in
         step (6) above.

       - The PDU is the value constructed in step (6) above.

       - The maxSizeResponseScopedPDU is a local value indicating the
         maximum size of a ScopedPDU that the application can accept.

       - The stateReference is the value from the processPdu call.

       - The statusInformation indicates that no error occurred and that
         a Response-Class PDU message should be generated.


Page 29

4 The Structure of the MIB Modules

There are three separate MIB modules described in this document, the management target MIB, the notification MIB, and the proxy MIB. The following sections describe the structure of these three MIB modules.

The use of these MIBs by particular types of applications is described later in this document:

   - The use of the management target MIB and the notification MIB in
     notification originator applications is described in section 5.

   - The use of the notification MIB for filtering notifications in
     notification originator applications is described in section 6.

   - The use of the management target MIB and the proxy MIB in proxy
     forwarding applications is described in section 7.

4.1 The Management Target MIB Module

The SNMP-TARGET-MIB module contains objects for defining management targets. It consists of two tables and conformance/compliance statements.

The first table, the snmpTargetAddrTable, contains information about transport domains and addresses. It also contains an object, snmpTargetAddrTagList, which provides a mechanism for grouping entries.

The second table, the snmpTargetParamsTable, contains information about SNMP version and security information to be used when sending messages to particular transport domains and addresses.

The Management Target MIB is intended to provide a general-purpose mechanism for specifying transport address, and for specifying parameters of SNMP messages generated by an SNMP entity. It is used within this document for generation of notifications and for proxy forwarding. However, it may be used for other purposes. If another document makes use of this MIB, that document is responsible for specifying how it is used. For example, [RFC2576] uses this MIB for source address validation of SNMPv1 messages.

4.1.1 Tag Lists

The snmpTargetAddrTagList object is used for grouping entries in the snmpTargetAddrTable. The value of this object contains a list of tag values which are used to select target addresses to be used for a particular operation.


Page 30

A tag value, which may also be used in MIB objects other than snmpTargetAddrTagList, is an arbitrary string of octets, but may not contain a delimiter character. Delimiter characters are defined to be one of the following characters:

   - An ASCII space character (0x20).

   - An ASCII TAB character (0x09).

   - An ASCII carriage return (CR) character (0x0D).

   - An ASCII line feed (LF) character (0x0A).

In addition, a tag value within a tag list may not have a zero length. Generally, a particular MIB object may contain either

   - a zero-length octet string representing an empty list, or

   - a single tag value, in which case the value of the MIB object may
     not contain a delimiter character, or

   - a list of tag values, separated by single delimiter characters.

For a list of tag values, these constraints imply certain restrictions on the value of a MIB object:

   - There cannot be a leading or trailing delimiter character.

   - There cannot be multiple adjacent delimiter characters.

4.1.2 Definitions

   SNMP-TARGET-MIB DEFINITIONS ::= BEGIN

IMPORTS
MODULE-IDENTITY,
OBJECT-TYPE,
snmpModules,
Counter32,
Integer32
FROM SNMPv2-SMI

TEXTUAL-CONVENTION,
TDomain,
TAddress,
TimeInterval,
RowStatus,
StorageType,


Page 31

TestAndIncr
FROM SNMPv2-TC

SnmpSecurityModel,
SnmpMessageProcessingModel,
SnmpSecurityLevel,
SnmpAdminString
FROM SNMP-FRAMEWORK-MIB

MODULE-COMPLIANCE,
OBJECT-GROUP
FROM SNMPv2-CONF;

snmpTargetMIB MODULE-IDENTITY
LAST-UPDATED "200210140000Z"
ORGANIZATION "IETF SNMPv3 Working Group"
CONTACT-INFO

           "WG-email:   snmpv3@lists.tislabs.com
            Subscribe:  majordomo@lists.tislabs.com
                        In message body:  subscribe snmpv3

            Co-Chair:   Russ Mundy
                        Network Associates Laboratories
            Postal:     15204 Omega Drive, Suite 300
                        Rockville, MD 20850-4601
                        USA
            EMail:      mundy@tislabs.com
            Phone:      +1 301-947-7107

            Co-Chair:   David Harrington
                        Enterasys Networks
            Postal:     35 Industrial Way
                        P. O. Box 5004
                        Rochester, New Hampshire 03866-5005
                        USA
            EMail:      dbh@enterasys.com
            Phone:      +1 603-337-2614

Co-editor: David B. Levi
Nortel Networks

            Postal:     3505 Kesterwood Drive
                        Knoxville, Tennessee 37918
            EMail:      dlevi@nortelnetworks.com
            Phone:      +1 865 686 0432

Co-editor: Paul Meyer
Secure Computing Corporation

            Postal:     2675 Long Lake Road


Page 32

Roseville, Minnesota 55113

            EMail:      paul_meyer@securecomputing.com
            Phone:      +1 651 628 1592

Co-editor: Bob Stewart
Retired"
DESCRIPTION
"This MIB module defines MIB objects which provide mechanisms to remotely configure the parameters used by an SNMP entity for the generation of SNMP messages.

Copyright © The Internet Society (2002). This
version of this MIB module is part of RFC 3413;
see the RFC itself for full legal notices.
"

       REVISION    "200210140000Z"             -- 14 October 2002
       DESCRIPTION "Fixed DISPLAY-HINTS for UTF-8 strings, fixed hex
                    value of LF characters, clarified meaning of zero
                    length tag values, improved tag list examples.
                    Published as RFC 3413."
       REVISION    "199808040000Z"             -- 4 August 1998
       DESCRIPTION "Clarifications, published as
                    RFC 2573."
       REVISION    "199707140000Z"             -- 14 July 1997
       DESCRIPTION "The initial revision, published as RFC2273."
       ::= { snmpModules 12 }

   snmpTargetObjects       OBJECT IDENTIFIER ::= { snmpTargetMIB 1 }
   snmpTargetConformance   OBJECT IDENTIFIER ::= { snmpTargetMIB 3 }

   SnmpTagValue ::= TEXTUAL-CONVENTION
       DISPLAY-HINT "255t"
       STATUS       current
       DESCRIPTION
           "An octet string containing a tag value.
            Tag values are preferably in human-readable form.

To facilitate internationalization, this information is represented using the ISO/IEC IS 10646-1 character set, encoded as an octet string using the UTF-8
character encoding scheme described in RFC 2279.

Since additional code points are added by amendments to the 10646 standard from time to time,
implementations must be prepared to encounter any code point from 0x00000000 to 0x7fffffff.

The use of control codes should be avoided, and certain


Page 33

control codes are not allowed as described below.

For code points not directly supported by user
interface hardware or software, an alternative means of entry and display, such as hexadecimal, may be provided.

For information encoded in 7-bit US-ASCII, the UTF-8 representation is identical to the US-ASCII encoding.

Note that when this TC is used for an object that is used or envisioned to be used as an index, then a SIZE restriction must be specified so that the number of sub-identifiers for any object instance does not exceed the limit of 128, as defined by [RFC1905].

An object of this type contains a single tag value which is used to select a set of entries in a table.

A tag value is an arbitrary string of octets, but may not contain a delimiter character. Delimiter characters are defined to be one of the following:

                -  An ASCII space character (0x20).

                -  An ASCII TAB character (0x09).

                -  An ASCII carriage return (CR) character (0x0D).

                -  An ASCII line feed (LF) character (0x0A).

Delimiter characters are used to separate tag values in a tag list. An object of this type may only
contain a single tag value, and so delimiter
characters are not allowed in a value of this type.

Note that a tag value of 0 length means that no tag is defined. In other words, a tag value of 0 length would never match anything in a tag list, and would never select any table entries.

Some examples of valid tag values are:

                - 'acme'

                - 'router'

                - 'host'


Page 34

The use of a tag value to select table entries is application and MIB specific."

       SYNTAX       OCTET STRING (SIZE (0..255))

   SnmpTagList ::= TEXTUAL-CONVENTION
       DISPLAY-HINT "255t"
       STATUS       current
       DESCRIPTION
           "An octet string containing a list of tag values.
            Tag values are preferably in human-readable form.

To facilitate internationalization, this information is represented using the ISO/IEC IS 10646-1 character set, encoded as an octet string using the UTF-8
character encoding scheme described in RFC 2279.

Since additional code points are added by amendments to the 10646 standard from time to time,
implementations must be prepared to encounter any code point from 0x00000000 to 0x7fffffff.

The use of control codes should be avoided, except as described below.

For code points not directly supported by user
interface hardware or software, an alternative means of entry and display, such as hexadecimal, may be provided.

For information encoded in 7-bit US-ASCII, the UTF-8 representation is identical to the US-ASCII encoding.

An object of this type contains a list of tag values which are used to select a set of entries in a table.

A tag value is an arbitrary string of octets, but may not contain a delimiter character. Delimiter characters are defined to be one of the following:

                -  An ASCII space character (0x20).

                -  An ASCII TAB character (0x09).

                -  An ASCII carriage return (CR) character (0x0D).

                -  An ASCII line feed (LF) character (0x0A).

Delimiter characters are used to separate tag values


Page 35

in a tag list. Only a single delimiter character may occur between two tag values. A tag value may not have a zero length. These constraints imply certain restrictions on the contents of this object:

                - There cannot be a leading or trailing delimiter
                  character.

                - There cannot be multiple adjacent delimiter
                  characters.

Some examples of valid tag lists are:

                - ''                        -- an empty list

                - 'acme'                    -- list of one tag

                - 'host router bridge'      -- list of several tags

Note that although a tag value may not have a length of zero, an empty string is still valid. This indicates an empty list (i.e. there are no tag values in the list).

The use of the tag list to select table entries is application and MIB specific. Typically, an application will provide one or more tag values, and any entry which contains some combination of these tag values will be selected."

       SYNTAX       OCTET STRING (SIZE (0..255))

   --
   --
   -- The snmpTargetObjects group
   --
   --

snmpTargetSpinLock OBJECT-TYPE

       SYNTAX      TestAndIncr
       MAX-ACCESS  read-write
       STATUS      current
       DESCRIPTION
           "This object is used to facilitate modification of table
            entries in the SNMP-TARGET-MIB module by multiple
            managers.  In particular, it is useful when modifying
            the value of the snmpTargetAddrTagList object.

The procedure for modifying the snmpTargetAddrTagList object is as follows:


Page 36

1 Retrieve the value of snmpTargetSpinLock and
of snmpTargetAddrTagList.

2 Generate a new value for snmpTargetAddrTagList.

3 Set the value of snmpTargetSpinLock to the
retrieved value, and the value of
snmpTargetAddrTagList to the new value. If the set fails for the snmpTargetSpinLock object, go back to step 1."
       ::= { snmpTargetObjects 1 }

snmpTargetAddrTable OBJECT-TYPE

       SYNTAX      SEQUENCE OF SnmpTargetAddrEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "A table of transport addresses to be used in the generation
            of SNMP messages."
       ::= { snmpTargetObjects 2 }

snmpTargetAddrEntry OBJECT-TYPE

       SYNTAX      SnmpTargetAddrEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "A transport address to be used in the generation
            of SNMP operations.

Entries in the snmpTargetAddrTable are created and deleted using the snmpTargetAddrRowStatus object." INDEX { IMPLIED snmpTargetAddrName }

       ::= { snmpTargetAddrTable 1 }

   SnmpTargetAddrEntry ::= SEQUENCE {
       snmpTargetAddrName         SnmpAdminString,
       snmpTargetAddrTDomain      TDomain,
       snmpTargetAddrTAddress     TAddress,
       snmpTargetAddrTimeout      TimeInterval,
       snmpTargetAddrRetryCount   Integer32,
       snmpTargetAddrTagList      SnmpTagList,
       snmpTargetAddrParams       SnmpAdminString,
       snmpTargetAddrStorageType  StorageType,
       snmpTargetAddrRowStatus    RowStatus
   }

snmpTargetAddrName OBJECT-TYPE

       SYNTAX      SnmpAdminString (SIZE(1..32))


Page 37

MAX-ACCESS not-accessible

       STATUS      current
       DESCRIPTION
           "The locally arbitrary, but unique identifier associated
            with this snmpTargetAddrEntry."
       ::= { snmpTargetAddrEntry 1 }

snmpTargetAddrTDomain OBJECT-TYPE

       SYNTAX      TDomain
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "This object indicates the transport type of the address
            contained in the snmpTargetAddrTAddress object."
       ::= { snmpTargetAddrEntry 2 }

snmpTargetAddrTAddress OBJECT-TYPE

       SYNTAX      TAddress
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "This object contains a transport address.  The format of
            this address depends on the value of the
            snmpTargetAddrTDomain object."
       ::= { snmpTargetAddrEntry 3 }

snmpTargetAddrTimeout OBJECT-TYPE

       SYNTAX      TimeInterval
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "This object should reflect the expected maximum round
            trip time for communicating with the transport address
            defined by this row.  When a message is sent to this
            address, and a response (if one is expected) is not
            received within this time period, an implementation
            may assume that the response will not be delivered.

Note that the time interval that an application waits for a response may actually be derived from the value of this object. The method for deriving the actual time interval is implementation dependent. One such method is to derive the expected round trip time based on a particular retransmission algorithm and on the number of timeouts which have occurred. The type of message may also be considered when deriving expected round trip times for retransmissions. For example, if a message is being sent with a securityLevel that indicates both


Page 38

authentication and privacy, the derived value may be increased to compensate for extra processing time spent during authentication and encryption processing." DEFVAL { 1500 }

       ::= { snmpTargetAddrEntry 4 }

snmpTargetAddrRetryCount OBJECT-TYPE

       SYNTAX      Integer32 (0..255)
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "This object specifies a default number of retries to be
            attempted when a response is not received for a generated
            message.  An application may provide its own retry count,
            in which case the value of this object is ignored."
       DEFVAL { 3 }
       ::= { snmpTargetAddrEntry 5 }

snmpTargetAddrTagList OBJECT-TYPE

       SYNTAX      SnmpTagList
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "This object contains a list of tag values which are
            used to select target addresses for a particular
            operation."
       DEFVAL { "" }
       ::= { snmpTargetAddrEntry 6 }

snmpTargetAddrParams OBJECT-TYPE

       SYNTAX      SnmpAdminString (SIZE(1..32))
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The value of this object identifies an entry in the
            snmpTargetParamsTable.  The identified entry
            contains SNMP parameters to be used when generating
            messages to be sent to this transport address."
       ::= { snmpTargetAddrEntry 7 }

snmpTargetAddrStorageType OBJECT-TYPE

       SYNTAX      StorageType
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The storage type for this conceptual row.
            Conceptual rows having the value 'permanent' need not
            allow write-access to any columnar objects in the row."


Page 39

DEFVAL { nonVolatile }

       ::= { snmpTargetAddrEntry 8 }

snmpTargetAddrRowStatus OBJECT-TYPE

       SYNTAX      RowStatus
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The status of this conceptual row.

To create a row in this table, a manager must
set this object to either createAndGo(4) or
createAndWait(5).

Until instances of all corresponding columns are appropriately configured, the value of the
corresponding instance of the snmpTargetAddrRowStatus column is 'notReady'.

In particular, a newly created row cannot be made active until the corresponding instances of
snmpTargetAddrTDomain, snmpTargetAddrTAddress, and snmpTargetAddrParams have all been set.

The following objects may not be modified while the value of this object is active(1):

                - snmpTargetAddrTDomain
                - snmpTargetAddrTAddress
            An attempt to set these objects while the value of
            snmpTargetAddrRowStatus is active(1) will result in
            an inconsistentValue error."
       ::= { snmpTargetAddrEntry 9 }

snmpTargetParamsTable OBJECT-TYPE

       SYNTAX      SEQUENCE OF SnmpTargetParamsEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "A table of SNMP target information to be used
            in the generation of SNMP messages."
       ::= { snmpTargetObjects 3 }

snmpTargetParamsEntry OBJECT-TYPE

       SYNTAX      SnmpTargetParamsEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "A set of SNMP target information.


Page 40

Entries in the snmpTargetParamsTable are created and deleted using the snmpTargetParamsRowStatus object." INDEX { IMPLIED snmpTargetParamsName }

       ::= { snmpTargetParamsTable 1 }

   SnmpTargetParamsEntry ::= SEQUENCE {
       snmpTargetParamsName           SnmpAdminString,
       snmpTargetParamsMPModel        SnmpMessageProcessingModel,
       snmpTargetParamsSecurityModel  SnmpSecurityModel,
       snmpTargetParamsSecurityName   SnmpAdminString,
       snmpTargetParamsSecurityLevel  SnmpSecurityLevel,
       snmpTargetParamsStorageType    StorageType,
       snmpTargetParamsRowStatus      RowStatus
   }

snmpTargetParamsName OBJECT-TYPE

       SYNTAX      SnmpAdminString (SIZE(1..32))
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "The locally arbitrary, but unique identifier associated
            with this snmpTargetParamsEntry."
       ::= { snmpTargetParamsEntry 1 }

snmpTargetParamsMPModel OBJECT-TYPE

       SYNTAX      SnmpMessageProcessingModel
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The Message Processing Model to be used when generating
            SNMP messages using this entry."
       ::= { snmpTargetParamsEntry 2 }

snmpTargetParamsSecurityModel OBJECT-TYPE

       SYNTAX      SnmpSecurityModel (1..2147483647)
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The Security Model to be used when generating SNMP
             messages using this entry.  An implementation may
             choose to return an inconsistentValue error if an
             attempt is made to set this variable to a value
             for a security model which the implementation does
             not support."
       ::= { snmpTargetParamsEntry 3 }

snmpTargetParamsSecurityName OBJECT-TYPE

       SYNTAX      SnmpAdminString


Page 41

MAX-ACCESS read-create

       STATUS      current
       DESCRIPTION
           "The securityName which identifies the Principal on
            whose behalf SNMP messages will be generated using
            this entry."
       ::= { snmpTargetParamsEntry 4 }

snmpTargetParamsSecurityLevel OBJECT-TYPE

       SYNTAX      SnmpSecurityLevel
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The Level of Security to be used when generating
            SNMP messages using this entry."
       ::= { snmpTargetParamsEntry 5 }

snmpTargetParamsStorageType OBJECT-TYPE

       SYNTAX      StorageType
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The storage type for this conceptual row.
            Conceptual rows having the value 'permanent' need not
            allow write-access to any columnar objects in the row."
       DEFVAL { nonVolatile }
       ::= { snmpTargetParamsEntry 6 }

snmpTargetParamsRowStatus OBJECT-TYPE

       SYNTAX      RowStatus
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The status of this conceptual row.

To create a row in this table, a manager must
set this object to either createAndGo(4) or
createAndWait(5).

Until instances of all corresponding columns are appropriately configured, the value of the
corresponding instance of the snmpTargetParamsRowStatus column is 'notReady'.

In particular, a newly created row cannot be made active until the corresponding
snmpTargetParamsMPModel,
snmpTargetParamsSecurityModel,


Page 42

snmpTargetParamsSecurityName,
and snmpTargetParamsSecurityLevel have all been set.

The following objects may not be modified while the value of this object is active(1):

                - snmpTargetParamsMPModel
                - snmpTargetParamsSecurityModel
                - snmpTargetParamsSecurityName
                - snmpTargetParamsSecurityLevel
            An attempt to set these objects while the value of
            snmpTargetParamsRowStatus is active(1) will result in
            an inconsistentValue error."
       ::= { snmpTargetParamsEntry 7 }

snmpUnavailableContexts OBJECT-TYPE

       SYNTAX       Counter32
       MAX-ACCESS   read-only
       STATUS       current
       DESCRIPTION
           "The total number of packets received by the SNMP
            engine which were dropped because the context
            contained in the message was unavailable."
       ::= { snmpTargetObjects 4 }

snmpUnknownContexts OBJECT-TYPE

       SYNTAX       Counter32
       MAX-ACCESS   read-only
       STATUS       current
       DESCRIPTION
           "The total number of packets received by the SNMP
            engine which were dropped because the context
            contained in the message was unknown."
       ::= { snmpTargetObjects 5 }

   --
   --
   -- Conformance information
   --
   --

   snmpTargetCompliances OBJECT IDENTIFIER ::=
                                           { snmpTargetConformance 1 }
   snmpTargetGroups      OBJECT IDENTIFIER ::=
                                           { snmpTargetConformance 2 }

   --
   --
   -- Compliance statements


Page 43

   --
   --

snmpTargetCommandResponderCompliance MODULE-COMPLIANCE

       STATUS      current
       DESCRIPTION
           "The compliance statement for SNMP entities which include
            a command responder application."
       MODULE -- This Module
           MANDATORY-GROUPS { snmpTargetCommandResponderGroup }
       ::= { snmpTargetCompliances 1 }

snmpTargetBasicGroup OBJECT-GROUP

       OBJECTS {
           snmpTargetSpinLock,
           snmpTargetAddrTDomain,
           snmpTargetAddrTAddress,
           snmpTargetAddrTagList,
           snmpTargetAddrParams,
           snmpTargetAddrStorageType,
           snmpTargetAddrRowStatus,
           snmpTargetParamsMPModel,
           snmpTargetParamsSecurityModel,
           snmpTargetParamsSecurityName,
           snmpTargetParamsSecurityLevel,
           snmpTargetParamsStorageType,
           snmpTargetParamsRowStatus
       }
       STATUS      current
       DESCRIPTION
           "A collection of objects providing basic remote
            configuration of management targets."
       ::= { snmpTargetGroups 1 }

snmpTargetResponseGroup OBJECT-GROUP

       OBJECTS {
           snmpTargetAddrTimeout,
           snmpTargetAddrRetryCount
       }
       STATUS      current
       DESCRIPTION
           "A collection of objects providing remote configuration
            of management targets for applications which generate
            SNMP messages for which a response message would be
            expected."
       ::= { snmpTargetGroups 2 }

snmpTargetCommandResponderGroup OBJECT-GROUP


Page 44

       OBJECTS {
           snmpUnavailableContexts,
           snmpUnknownContexts
       }
       STATUS      current
       DESCRIPTION
           "A collection of objects required for command responder
            applications, used for counting error conditions."
       ::= { snmpTargetGroups 3 }

END

4.2 The Notification MIB Module

The SNMP-NOTIFICATION-MIB module contains objects for the remote configuration of the parameters used by an SNMP entity for the generation of notifications. It consists of three tables and conformance/compliance statements. The first table, the
snmpNotifyTable, contains entries which select which entries in the snmpTargetAddrTable should be used for generating notifications, and the type of notifications to be generated.

The second table, the snmpNotifyFilterProfileTable, sparsely augments the snmpTargetParamsTable with an object which is used to associate a set of filters with a particular management target.

The third table, the snmpNotifyFilterTable, defines filters which are used to limit the number of notifications which are generated using particular management targets.

4.2.1 Definitions

   SNMP-NOTIFICATION-MIB DEFINITIONS ::= BEGIN

IMPORTS
MODULE-IDENTITY,
OBJECT-TYPE,
snmpModules
FROM SNMPv2-SMI

RowStatus,
StorageType
FROM SNMPv2-TC

SnmpAdminString
FROM SNMP-FRAMEWORK-MIB

SnmpTagValue,


Page 45

snmpTargetParamsName
FROM SNMP-TARGET-MIB

MODULE-COMPLIANCE,
OBJECT-GROUP
FROM SNMPv2-CONF;

snmpNotificationMIB MODULE-IDENTITY
LAST-UPDATED "200210140000Z"
ORGANIZATION "IETF SNMPv3 Working Group"
CONTACT-INFO

           "WG-email:   snmpv3@lists.tislabs.com
            Subscribe:  majordomo@lists.tislabs.com
                        In message body:  subscribe snmpv3

            Co-Chair:   Russ Mundy
                        Network Associates Laboratories
            Postal:     15204 Omega Drive, Suite 300
                        Rockville, MD 20850-4601
                        USA
            EMail:      mundy@tislabs.com
            Phone:      +1 301-947-7107

            Co-Chair:   David Harrington
                        Enterasys Networks
            Postal:     35 Industrial Way
                        P. O. Box 5004
                        Rochester, New Hampshire 03866-5005
                        USA
            EMail:      dbh@enterasys.com
            Phone:      +1 603-337-2614

Co-editor: David B. Levi
Nortel Networks

            Postal:     3505 Kesterwood Drive
                        Knoxville, Tennessee 37918
            EMail:      dlevi@nortelnetworks.com
            Phone:      +1 865 686 0432

Co-editor: Paul Meyer
Secure Computing Corporation

            Postal:     2675 Long Lake Road
                        Roseville, Minnesota 55113
            EMail:      paul_meyer@securecomputing.com
            Phone:      +1 651 628 1592

Co-editor: Bob Stewart
Retired"


Page 46

DESCRIPTION
"This MIB module defines MIB objects which provide mechanisms to remotely configure the parameters
used by an SNMP entity for the generation of
notifications.

Copyright © The Internet Society (2002). This
version of this MIB module is part of RFC 3413;
see the RFC itself for full legal notices.
"

       REVISION    "200210140000Z"             -- 14 October 2002
       DESCRIPTION "Clarifications, published as
                    RFC 3413."
       REVISION    "199808040000Z"             -- 4 August 1998
       DESCRIPTION "Clarifications, published as
                    RFC 2573."
       REVISION    "199707140000Z"             -- 14 July 1997
       DESCRIPTION "The initial revision, published as RFC2273."
       ::= { snmpModules 13 }

   snmpNotifyObjects       OBJECT IDENTIFIER ::=
                                             { snmpNotificationMIB 1 }
   snmpNotifyConformance   OBJECT IDENTIFIER ::=
                                             { snmpNotificationMIB 3 }

   --
   --
   -- The snmpNotifyObjects group
   --
   --

snmpNotifyTable OBJECT-TYPE

       SYNTAX      SEQUENCE OF SnmpNotifyEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "This table is used to select management targets which should
            receive notifications, as well as the type of notification
            which should be sent to each selected management target."
       ::= { snmpNotifyObjects 1 }

snmpNotifyEntry OBJECT-TYPE

       SYNTAX      SnmpNotifyEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "An entry in this table selects a set of management targets
            which should receive notifications, as well as the type of


Page 47

notification which should be sent to each selected management target.

Entries in the snmpNotifyTable are created and
deleted using the snmpNotifyRowStatus object."
INDEX { IMPLIED snmpNotifyName }

       ::= { snmpNotifyTable 1 }

   SnmpNotifyEntry ::= SEQUENCE {
       snmpNotifyName         SnmpAdminString,
       snmpNotifyTag          SnmpTagValue,
       snmpNotifyType         INTEGER,
       snmpNotifyStorageType  StorageType,
       snmpNotifyRowStatus    RowStatus
   }

snmpNotifyName OBJECT-TYPE

       SYNTAX      SnmpAdminString (SIZE(1..32))
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "The locally arbitrary, but unique identifier associated
            with this snmpNotifyEntry."
       ::= { snmpNotifyEntry 1 }

snmpNotifyTag OBJECT-TYPE

       SYNTAX      SnmpTagValue
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "This object contains a single tag value which is used
            to select entries in the snmpTargetAddrTable.  Any entry
            in the snmpTargetAddrTable which contains a tag value
            which is equal to the value of an instance of this
            object is selected.  If this object contains a value
            of zero length, no entries are selected."
       DEFVAL { "" }
       ::= { snmpNotifyEntry 2 }

snmpNotifyType OBJECT-TYPE

       SYNTAX      INTEGER {
                       trap(1),
                       inform(2)
                   }
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "This object determines the type of notification to


Page 48

be generated for entries in the snmpTargetAddrTable selected by the corresponding instance of
snmpNotifyTag. This value is only used when
generating notifications, and is ignored when
using the snmpTargetAddrTable for other purposes.

If the value of this object is trap(1), then any messages generated for selected rows will contain Unconfirmed-Class PDUs.

If the value of this object is inform(2), then any messages generated for selected rows will contain Confirmed-Class PDUs.

Note that if an SNMP entity only supports
generation of Unconfirmed-Class PDUs (and not
Confirmed-Class PDUs), then this object may be
read-only."
DEFVAL { trap }

       ::= { snmpNotifyEntry 3 }

snmpNotifyStorageType OBJECT-TYPE

       SYNTAX      StorageType
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The storage type for this conceptual row.
            Conceptual rows having the value 'permanent' need not
            allow write-access to any columnar objects in the row."
       DEFVAL { nonVolatile }
       ::= { snmpNotifyEntry 4 }

snmpNotifyRowStatus OBJECT-TYPE

       SYNTAX      RowStatus
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The status of this conceptual row.

To create a row in this table, a manager must
set this object to either createAndGo(4) or
createAndWait(5)."

       ::= { snmpNotifyEntry 5 }

snmpNotifyFilterProfileTable OBJECT-TYPE

       SYNTAX      SEQUENCE OF SnmpNotifyFilterProfileEntry
       MAX-ACCESS  not-accessible
       STATUS      current


Page 49

DESCRIPTION
"This table is used to associate a notification filter profile with a particular set of target parameters."

       ::= { snmpNotifyObjects 2 }

snmpNotifyFilterProfileEntry OBJECT-TYPE

       SYNTAX      SnmpNotifyFilterProfileEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "An entry in this table indicates the name of the filter
            profile to be used when generating notifications using
            the corresponding entry in the snmpTargetParamsTable.

Entries in the snmpNotifyFilterProfileTable are created and deleted using the snmpNotifyFilterProfileRowStatus object."
INDEX { IMPLIED snmpTargetParamsName }

       ::= { snmpNotifyFilterProfileTable 1 }

   SnmpNotifyFilterProfileEntry ::= SEQUENCE {
       snmpNotifyFilterProfileName         SnmpAdminString,
       snmpNotifyFilterProfileStorType     StorageType,
       snmpNotifyFilterProfileRowStatus    RowStatus
   }

snmpNotifyFilterProfileName OBJECT-TYPE

       SYNTAX      SnmpAdminString (SIZE(1..32))
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The name of the filter profile to be used when generating
            notifications using the corresponding entry in the
            snmpTargetAddrTable."
       ::= { snmpNotifyFilterProfileEntry 1 }

snmpNotifyFilterProfileStorType OBJECT-TYPE

       SYNTAX      StorageType
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The storage type for this conceptual row.
            Conceptual rows having the value 'permanent' need not
            allow write-access to any columnar objects in the row."
       DEFVAL { nonVolatile }
       ::= { snmpNotifyFilterProfileEntry 2 }

snmpNotifyFilterProfileRowStatus OBJECT-TYPE


Page 50

       SYNTAX      RowStatus
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The status of this conceptual row.

To create a row in this table, a manager must
set this object to either createAndGo(4) or
createAndWait(5).

Until instances of all corresponding columns are appropriately configured, the value of the
corresponding instance of the
snmpNotifyFilterProfileRowStatus column is 'notReady'.

In particular, a newly created row cannot be made active until the corresponding instance of
snmpNotifyFilterProfileName has been set."

       ::= { snmpNotifyFilterProfileEntry 3 }

snmpNotifyFilterTable OBJECT-TYPE

       SYNTAX      SEQUENCE OF SnmpNotifyFilterEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "The table of filter profiles.  Filter profiles are used
            to determine whether particular management targets should
            receive particular notifications.

When a notification is generated, it must be compared with the filters associated with each management target which is configured to receive notifications, in order to determine whether it may be sent to each such management target.

A more complete discussion of notification filtering can be found in section 6. of [SNMP-APPL]."

       ::= { snmpNotifyObjects 3 }

snmpNotifyFilterEntry OBJECT-TYPE

       SYNTAX      SnmpNotifyFilterEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "An element of a filter profile.

Entries in the snmpNotifyFilterTable are created and deleted using the snmpNotifyFilterRowStatus object."


Page 51

       INDEX {         snmpNotifyFilterProfileName,
               IMPLIED snmpNotifyFilterSubtree }
       ::= { snmpNotifyFilterTable 1 }

   SnmpNotifyFilterEntry ::= SEQUENCE {
       snmpNotifyFilterSubtree           OBJECT IDENTIFIER,
       snmpNotifyFilterMask              OCTET STRING,
       snmpNotifyFilterType              INTEGER,
       snmpNotifyFilterStorageType       StorageType,
       snmpNotifyFilterRowStatus         RowStatus
   }

snmpNotifyFilterSubtree OBJECT-TYPE

       SYNTAX      OBJECT IDENTIFIER
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "The MIB subtree which, when combined with the corresponding
            instance of snmpNotifyFilterMask, defines a family of
            subtrees which are included in or excluded from the
            filter profile."
       ::= { snmpNotifyFilterEntry 1 }

snmpNotifyFilterMask OBJECT-TYPE

       SYNTAX      OCTET STRING (SIZE(0..16))
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The bit mask which, in combination with the corresponding
            instance of snmpNotifyFilterSubtree, defines a family of
            subtrees which are included in or excluded from the
            filter profile.

Each bit of this bit mask corresponds to a
sub-identifier of snmpNotifyFilterSubtree, with the most significant bit of the i-th octet of this octet string value (extended if necessary, see below)
corresponding to the (8*i - 7)-th sub-identifier, and the least significant bit of the i-th octet of this octet string corresponding to the (8*i)-th
sub-identifier, where i is in the range 1 through 16.

Each bit of this bit mask specifies whether or not the corresponding sub-identifiers must match when determining if an OBJECT IDENTIFIER matches this family of filter subtrees; a '1' indicates that an exact match must occur; a '0' indicates 'wild card', i.e., any sub-identifier value matches.


Page 52

Thus, the OBJECT IDENTIFIER X of an object instance is contained in a family of filter subtrees if, for each sub-identifier of the value of
snmpNotifyFilterSubtree, either:

the i-th bit of snmpNotifyFilterMask is 0, or

the i-th sub-identifier of X is equal to the i-th sub-identifier of the value of
snmpNotifyFilterSubtree.

If the value of this bit mask is M bits long and there are more than M sub-identifiers in the
corresponding instance of snmpNotifyFilterSubtree, then the bit mask is extended with 1's to be the required length.

Note that when the value of this object is the
zero-length string, this extension rule results in a mask of all-1's being used (i.e., no 'wild card'), and the family of filter subtrees is the one
subtree uniquely identified by the corresponding instance of snmpNotifyFilterSubtree."
DEFVAL { ''H }

       ::= { snmpNotifyFilterEntry 2 }

snmpNotifyFilterType OBJECT-TYPE

       SYNTAX      INTEGER {
                       included(1),
                       excluded(2)
                   }
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "This object indicates whether the family of filter subtrees
            defined by this entry are included in or excluded from a
            filter.  A more detailed discussion of the use of this
            object can be found in section 6. of [SNMP-APPL]."
       DEFVAL { included }
       ::= { snmpNotifyFilterEntry 3 }

snmpNotifyFilterStorageType OBJECT-TYPE

       SYNTAX      StorageType
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The storage type for this conceptual row.
            Conceptual rows having the value 'permanent' need not


Page 53

allow write-access to any columnar objects in the row." DEFVAL { nonVolatile }

       ::= { snmpNotifyFilterEntry 4 }

snmpNotifyFilterRowStatus OBJECT-TYPE

       SYNTAX      RowStatus
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The status of this conceptual row.

To create a row in this table, a manager must
set this object to either createAndGo(4) or
createAndWait(5)."

       ::= { snmpNotifyFilterEntry 5 }

   --
   --
   -- Conformance information
   --
   --

   snmpNotifyCompliances OBJECT IDENTIFIER ::=
                                           { snmpNotifyConformance 1 }
   snmpNotifyGroups      OBJECT IDENTIFIER ::=
                                           { snmpNotifyConformance 2 }

   --
   --
   -- Compliance statements
   --
   --

snmpNotifyBasicCompliance MODULE-COMPLIANCE

       STATUS      current
       DESCRIPTION
           "The compliance statement for minimal SNMP entities which
            implement only SNMP Unconfirmed-Class notifications and
            read-create operations on only the snmpTargetAddrTable."
       MODULE SNMP-TARGET-MIB
           MANDATORY-GROUPS { snmpTargetBasicGroup }

OBJECT snmpTargetParamsMPModel

           MIN-ACCESS    read-only
           DESCRIPTION
               "Create/delete/modify access is not required."

OBJECT snmpTargetParamsSecurityModel


Page 54

           MIN-ACCESS    read-only
           DESCRIPTION
               "Create/delete/modify access is not required."

OBJECT snmpTargetParamsSecurityName

           MIN-ACCESS    read-only
           DESCRIPTION
               "Create/delete/modify access is not required."

OBJECT snmpTargetParamsSecurityLevel

           MIN-ACCESS    read-only
           DESCRIPTION
               "Create/delete/modify access is not required."

OBJECT snmpTargetParamsStorageType

           SYNTAX INTEGER {
               readOnly(5)
           }
           MIN-ACCESS    read-only
           DESCRIPTION
               "Create/delete/modify access is not required.
                Support of the values other(1), volatile(2),
                nonVolatile(3), and permanent(4) is not required."

OBJECT snmpTargetParamsRowStatus

           SYNTAX INTEGER {
               active(1)
           }
           MIN-ACCESS    read-only
           DESCRIPTION
               "Create/delete/modify access to the
                snmpTargetParamsTable is not required.
                Support of the values notInService(2), notReady(3),
                createAndGo(4), createAndWait(5), and destroy(6) is
                not required."

MODULE -- This Module
MANDATORY-GROUPS { snmpNotifyGroup }

OBJECT snmpNotifyTag

           MIN-ACCESS    read-only
           DESCRIPTION
               "Create/delete/modify access is not required."

OBJECT snmpNotifyType

           SYNTAX INTEGER {
               trap(1)
           }


Page 55

           MIN-ACCESS    read-only
           DESCRIPTION
               "Create/delete/modify access is not required.
                Support of the value notify(2) is not required."

OBJECT snmpNotifyStorageType

           SYNTAX INTEGER {
               readOnly(5)
           }
           MIN-ACCESS    read-only
           DESCRIPTION
               "Create/delete/modify access is not required.
                Support of the values other(1), volatile(2),
                nonVolatile(3), and permanent(4) is not required."

OBJECT snmpNotifyRowStatus

           SYNTAX INTEGER {
               active(1)
           }
           MIN-ACCESS    read-only
           DESCRIPTION
               "Create/delete/modify access to the
                snmpNotifyTable is not required.
                Support of the values notInService(2), notReady(3),
                createAndGo(4), createAndWait(5), and destroy(6) is
                not required."

       ::= { snmpNotifyCompliances 1 }

snmpNotifyBasicFiltersCompliance MODULE-COMPLIANCE

       STATUS      current
       DESCRIPTION
           "The compliance statement for SNMP entities which implement
            SNMP Unconfirmed-Class notifications with filtering, and
            read-create operations on all related tables."
       MODULE SNMP-TARGET-MIB
           MANDATORY-GROUPS { snmpTargetBasicGroup }
       MODULE -- This Module
           MANDATORY-GROUPS { snmpNotifyGroup,
                              snmpNotifyFilterGroup }
       ::= { snmpNotifyCompliances 2 }

snmpNotifyFullCompliance MODULE-COMPLIANCE

       STATUS      current
       DESCRIPTION
           "The compliance statement for SNMP entities which either
            implement only SNMP Confirmed-Class notifications, or both
            SNMP Unconfirmed-Class and Confirmed-Class notifications,


Page 56

plus filtering and read-create operations on all related tables."
MODULE SNMP-TARGET-MIB
MANDATORY-GROUPS { snmpTargetBasicGroup,
snmpTargetResponseGroup }
MODULE -- This Module
MANDATORY-GROUPS { snmpNotifyGroup,
snmpNotifyFilterGroup }

       ::= { snmpNotifyCompliances 3 }

snmpNotifyGroup OBJECT-GROUP

       OBJECTS {
           snmpNotifyTag,
           snmpNotifyType,
           snmpNotifyStorageType,
           snmpNotifyRowStatus
       }
       STATUS      current
       DESCRIPTION
           "A collection of objects for selecting which management
            targets are used for generating notifications, and the
            type of notification to be generated for each selected
            management target."
       ::= { snmpNotifyGroups 1 }

snmpNotifyFilterGroup OBJECT-GROUP

       OBJECTS {
           snmpNotifyFilterProfileName,
           snmpNotifyFilterProfileStorType,
           snmpNotifyFilterProfileRowStatus,
           snmpNotifyFilterMask,
           snmpNotifyFilterType,
           snmpNotifyFilterStorageType,
           snmpNotifyFilterRowStatus
       }
       STATUS      current
       DESCRIPTION
           "A collection of objects providing remote configuration
            of notification filters."
       ::= { snmpNotifyGroups 2 }

END


Page 57

4.3 The Proxy MIB Module

The SNMP-PROXY-MIB module, which defines MIB objects that provide mechanisms to remotely configure the parameters used by an SNMP entity for proxy forwarding operations, contains a single table. This table, snmpProxyTable, is used to define translations between management targets for use when forwarding messages.

4.3.1 Definitions

   SNMP-PROXY-MIB DEFINITIONS ::= BEGIN

IMPORTS
MODULE-IDENTITY,
OBJECT-TYPE,
snmpModules
FROM SNMPv2-SMI

RowStatus,
StorageType
FROM SNMPv2-TC

SnmpEngineID,
SnmpAdminString
FROM SNMP-FRAMEWORK-MIB

SnmpTagValue
FROM SNMP-TARGET-MIB

MODULE-COMPLIANCE,
OBJECT-GROUP
FROM SNMPv2-CONF;

snmpProxyMIB MODULE-IDENTITY
LAST-UPDATED "200210140000Z"
ORGANIZATION "IETF SNMPv3 Working Group"
CONTACT-INFO

           "WG-email:   snmpv3@lists.tislabs.com
            Subscribe:  majordomo@lists.tislabs.com
                        In message body:  subscribe snmpv3

            Co-Chair:   Russ Mundy
                        Network Associates Laboratories
            Postal:     15204 Omega Drive, Suite 300
                        Rockville, MD 20850-4601
                        USA
            EMail:      mundy@tislabs.com
            Phone:      +1 301-947-7107


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            Co-Chair:   David Harrington
                        Enterasys Networks
            Postal:     35 Industrial Way
                        P. O. Box 5004
                        Rochester, New Hampshire 03866-5005
                        USA
            EMail:      dbh@enterasys.com
            Phone:      +1 603-337-2614

Co-editor: David B. Levi
Nortel Networks

            Postal:     3505 Kesterwood Drive
                        Knoxville, Tennessee 37918
            EMail:      dlevi@nortelnetworks.com
            Phone:      +1 865 686 0432

Co-editor: Paul Meyer
Secure Computing Corporation

            Postal:     2675 Long Lake Road
                        Roseville, Minnesota 55113
            EMail:      paul_meyer@securecomputing.com
            Phone:      +1 651 628 1592

Co-editor: Bob Stewart
Retired"
DESCRIPTION
"This MIB module defines MIB objects which provide mechanisms to remotely configure the parameters
used by a proxy forwarding application.

Copyright © The Internet Society (2002). This
version of this MIB module is part of RFC 3413;
see the RFC itself for full legal notices.
"

       REVISION    "200210140000Z"             -- 14 October 2002
       DESCRIPTION "Clarifications, published as
                    RFC 3413."
       REVISION    "199808040000Z"             -- 4 August 1998
       DESCRIPTION "Clarifications, published as
                    RFC 2573."
       REVISION    "199707140000Z"             -- 14 July 1997
       DESCRIPTION "The initial revision, published as RFC2273."
       ::= { snmpModules 14 }

   snmpProxyObjects        OBJECT IDENTIFIER ::= { snmpProxyMIB 1 }
   snmpProxyConformance    OBJECT IDENTIFIER ::= { snmpProxyMIB 3 }

   --


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   --
   -- The snmpProxyObjects group
   --
   --

snmpProxyTable OBJECT-TYPE

       SYNTAX      SEQUENCE OF SnmpProxyEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "The table of translation parameters used by proxy forwarder
            applications for forwarding SNMP messages."
       ::= { snmpProxyObjects 2 }

snmpProxyEntry OBJECT-TYPE

       SYNTAX      SnmpProxyEntry
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "A set of translation parameters used by a proxy forwarder
            application for forwarding SNMP messages.

Entries in the snmpProxyTable are created and deleted using the snmpProxyRowStatus object."
INDEX { IMPLIED snmpProxyName }

       ::= { snmpProxyTable 1 }

   SnmpProxyEntry ::= SEQUENCE {
       snmpProxyName               SnmpAdminString,
       snmpProxyType               INTEGER,
       snmpProxyContextEngineID    SnmpEngineID,
       snmpProxyContextName        SnmpAdminString,
       snmpProxyTargetParamsIn     SnmpAdminString,
       snmpProxySingleTargetOut    SnmpAdminString,
       snmpProxyMultipleTargetOut  SnmpTagValue,
       snmpProxyStorageType        StorageType,
       snmpProxyRowStatus          RowStatus
   }

snmpProxyName OBJECT-TYPE

       SYNTAX      SnmpAdminString (SIZE(1..32))
       MAX-ACCESS  not-accessible
       STATUS      current
       DESCRIPTION
           "The locally arbitrary, but unique identifier associated
            with this snmpProxyEntry."
       ::= { snmpProxyEntry 1 }


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snmpProxyType OBJECT-TYPE

       SYNTAX      INTEGER {
                       read(1),
                       write(2),
                       trap(3),
                       inform(4)
                   }
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The type of message that may be forwarded using
            the translation parameters defined by this entry."
       ::= { snmpProxyEntry 2 }

snmpProxyContextEngineID OBJECT-TYPE

       SYNTAX      SnmpEngineID
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The contextEngineID contained in messages that
            may be forwarded using the translation parameters
            defined by this entry."
       ::= { snmpProxyEntry 3 }

snmpProxyContextName OBJECT-TYPE

       SYNTAX      SnmpAdminString
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The contextName contained in messages that may be
            forwarded using the translation parameters defined
            by this entry.

This object is optional, and if not supported, the contextName contained in a message is ignored when selecting an entry in the snmpProxyTable."

       ::= { snmpProxyEntry 4 }

snmpProxyTargetParamsIn OBJECT-TYPE

       SYNTAX      SnmpAdminString
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "This object selects an entry in the snmpTargetParamsTable.
            The selected entry is used to determine which row of the
            snmpProxyTable to use for forwarding received messages."
       ::= { snmpProxyEntry 5 }


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snmpProxySingleTargetOut OBJECT-TYPE

       SYNTAX      SnmpAdminString
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "This object selects a management target defined in the
            snmpTargetAddrTable (in the SNMP-TARGET-MIB).  The
            selected target is defined by an entry in the
            snmpTargetAddrTable whose index value (snmpTargetAddrName)
            is equal to this object.

This object is only used when selection of a single target is required (i.e. when forwarding an incoming read or write request)."

       ::= { snmpProxyEntry 6 }

snmpProxyMultipleTargetOut OBJECT-TYPE

       SYNTAX      SnmpTagValue
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "This object selects a set of management targets defined
            in the snmpTargetAddrTable (in the SNMP-TARGET-MIB).

This object is only used when selection of multiple targets is required (i.e. when forwarding an incoming notification)."

       ::= { snmpProxyEntry 7 }

snmpProxyStorageType OBJECT-TYPE

       SYNTAX      StorageType
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The storage type of this conceptual row.
            Conceptual rows having the value 'permanent' need not
            allow write-access to any columnar objects in the row."
       DEFVAL { nonVolatile }
       ::= { snmpProxyEntry 8 }

snmpProxyRowStatus OBJECT-TYPE

       SYNTAX      RowStatus
       MAX-ACCESS  read-create
       STATUS      current
       DESCRIPTION
           "The status of this conceptual row.

To create a row in this table, a manager must


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set this object to either createAndGo(4) or
createAndWait(5).

The following objects may not be modified while the value of this object is active(1):

                - snmpProxyType
                - snmpProxyContextEngineID
                - snmpProxyContextName
                - snmpProxyTargetParamsIn
                - snmpProxySingleTargetOut
                - snmpProxyMultipleTargetOut"
       ::= { snmpProxyEntry 9 }

   --
   --
   -- Conformance information
   --
   --

   snmpProxyCompliances OBJECT IDENTIFIER ::=
                                            { snmpProxyConformance 1 }
   snmpProxyGroups      OBJECT IDENTIFIER ::=
                                            { snmpProxyConformance 2 }

   --
   --
   -- Compliance statements
   --
   --

snmpProxyCompliance MODULE-COMPLIANCE

       STATUS      current
       DESCRIPTION
           "The compliance statement for SNMP entities which include
            a proxy forwarding application."
       MODULE SNMP-TARGET-MIB
           MANDATORY-GROUPS { snmpTargetBasicGroup,
                              snmpTargetResponseGroup }
       MODULE -- This Module
           MANDATORY-GROUPS { snmpProxyGroup }
       ::= { snmpProxyCompliances 1 }

snmpProxyGroup OBJECT-GROUP

       OBJECTS {
           snmpProxyType,
           snmpProxyContextEngineID,
           snmpProxyContextName,
           snmpProxyTargetParamsIn,


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snmpProxySingleTargetOut,
snmpProxyMultipleTargetOut,
snmpProxyStorageType,
snmpProxyRowStatus
}

       STATUS      current
       DESCRIPTION
           "A collection of objects providing remote configuration of
            management target translation parameters for use by
            proxy forwarder applications."
       ::= { snmpProxyGroups 3 }

END

5 Identification of Management Targets in Notification Originators

This section describes the mechanisms used by a notification originator application when using the MIB module described in this document to determine the set of management targets to be used when generating a notification.

A notification originator uses all active entries in the
snmpNotifyTable to find the management targets to be used for generating notifications. Each active entry in this table selects zero or more entries in the snmpTargetAddrTable. When a notification is generated, it is sent to all of the targets specified by the selected snmpTargetAddrTable entries (subject to the application of access control and notification filtering).

Any entry in the snmpTargetAddrTable whose snmpTargetAddrTagList object contains a tag value which is equal to a value of
snmpNotifyTag is selected by the snmpNotifyEntry which contains that instance of snmpNotif