Please refer to the current edition of the "Internet Official Protocol Standards&#34

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Obsoletes: 1271 February 1995 Category: Standards Track

Remote Network Monitoring Management Information Base 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 memo defines a portion of the Management Information Base (MIB) for use with network management protocols in TCP/IP-based internets.

In particular, it defines objects for managing remote network monitoring devices.

Table of Contents

1. The Network Management Framework ... 2

2. Overview ... 3

2.1 Remote Network Management Goals ... 3

2.2 Textual Conventions ... 5

2.3 Structure of MIB ... 5

2.3.1 The Ethernet Statistics Group ... 6

2.3.2 The History Control Group ... 6

2.3.3 The Ethernet History Group ... 6

2.3.4 The Alarm Group ... 6

2.3.5 The Host Group ... 6

2.3.6 The HostTopN Group ... 7

2.3.7 The Matrix Group ... 7

2.3.8 The Filter Group ... 7

2.3.9 The Packet Capture Group ... 7

2.3.10 The Event Group ... 7

3. Control of Remote Network Monitoring Devices ... 7

3.1 Resource Sharing Among Multiple Management Stations .. 8

3.2 Row Addition Among Multiple Management Stations ... 10

4. Conventions ... 11

5. Definitions ... 11

6. Acknowledgments ... 89

7. References ... 89

8. Security Considerations ... 90

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9. Author’s Address ... 90 10. Appendix: Changes from RFC 1271 ... 91 1. The Network Management Framework

The Internet-standard Network Management Framework consists of three components. They are:

STD 16, RFC 1155 [1] which defines the SMI, the mechanisms used for describing and naming objects for the purpose of management.

STD 16, RFC 1212 [2] defines a more concise description mechanism, which is wholly consistent with the SMI.

STD 17, RFC 1213 [3] which defines MIB-II, the core set of managed objects for the Internet suite of protocols.

STD 15, RFC 1157 [4] which defines the SNMP, the protocol used for network access to managed objects.

The Framework permits new objects to be defined for the purpose of experimentation and evaluation.

Managed objects are accessed via a virtual information store, termed the Management Information Base or MIB. Within a given MIB module, objects are defined using RFC 1212’s OBJECT-TYPE macro. At a

minimum, each object has a name, a syntax, an access-level, and an implementation-status.

The name is an object identifier, an administratively assigned name, which specifies an object type. The object type together with an object instance serves to uniquely identify a specific instantiation of the object. For human convenience, we often use a textual string, termed the object descriptor, to also refer to the object type.

The syntax of an object type defines the abstract data structure corresponding to that object type. The ASN.1[5] language is used for this purpose. However, RFC 1155 purposely restricts the ASN.1

constructs which may be used. These restrictions are explicitly made for simplicity.

The access-level of an object type defines whether it makes "protocol sense" to read and/or write the value of an instance of the object type. (This access-level is independent of any administrative authorization policy.)

The implementation-status of an object type indicates whether the object is mandatory, optional, obsolete, or deprecated.

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2. Overview

Remote network monitoring devices, often called monitors or probes, are instruments that exist for the purpose of managing a network.

Often these remote probes are stand-alone devices and devote significant internal resources for the sole purpose of managing a network. An organization may employ many of these devices, one per network segment, to manage its internet. In addition, these devices may be used for a network management service provider to access a client network, often geographically remote.

The objects defined in this document are intended as an interface between an RMON agent and an RMON management application and are not intended for direct manipulation by humans. While some users may tolerate the direct display of some of these objects, few will tolerate the complexity of manually manipulating objects to

accomplish row creation. These functions should be handled by the management application.

While most of the objects in this document are suitable for the management of any type of network, there are some which are specific to managing Ethernet networks. These are the objects in the

etherStatsTable, the etherHistoryTable, and some attributes of the filterPktStatus and capturBufferPacketStatus objects. The design of this MIB allows similar objects to be defined for other network types. It is intended that future versions of this document and additional documents will define extensions for other network types such as Token Ring and FDDI.

2.1. Remote Network Management Goals o Offline Operation

There are sometimes conditions when a management station will not be in constant contact with its remote monitoring devices. This is sometimes by design in an attempt to lower communications costs (especially when communicating over a WAN or

dialup link), or by accident as network failures affect the communications between the management station and the probe.

For this reason, this MIB allows a probe to be configured to perform diagnostics and to collect statistics continuously, even when communication with the management station may not be possible or

efficient. The probe may then attempt to notify the management station when an exceptional condition occurs. Thus, even in circumstances where

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communication between management station and probe is not continuous, fault, performance, and configuration information may be continuously accumulated and

communicated to the management station conveniently and efficiently.

o Proactive Monitoring

Given the resources available on the monitor, it is potentially helpful for it continuously to run diagnostics and to log network performance. The monitor is always available at the onset of any

failure. It can notify the management station of the failure and can store historical statistical

information about the failure. This historical information can be played back by the management station in an attempt to perform further diagnosis into the cause of the problem.

o Problem Detection and Reporting

The monitor can be configured to recognize conditions, most notably error conditions, and continuously to check for them. When one of these conditions occurs, the event may be logged, and management stations may be notified in a number of ways.

o Value Added Data

Because a remote monitoring device represents a network resource dedicated exclusively to network management functions, and because it is located

directly on the monitored portion of the network, the remote network monitoring device has the opportunity to add significant value to the data it collects.

For instance, by highlighting those hosts on the network that generate the most traffic or errors, the probe can give the management station precisely the information it needs to solve a class of problems.

o Multiple Managers

An organization may have multiple management stations for different units of the organization, for different functions (e.g. engineering and operations), and in an attempt to provide disaster recovery. Because

environments with multiple management stations are common, the remote network monitoring device has to deal with more than own management station,

potentially using its resources concurrently.

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2.2. Textual Conventions

Two new data types are introduced as a textual convention in this MIB document. These textual conventions enhance the readability of the specification and can ease comparison with other specifications if appropriate. It should be noted that the introduction of the these textual conventions has no effect on either the syntax nor the semantics of any managed objects. The use of these is merely an artifact of the explanatory method used. Objects defined in terms of one of these methods are always encoded by means of the rules that define the primitive type. Hence, no changes to the SMI or the SNMP are necessary to accommodate these textual conventions which are adopted merely for the convenience of readers and writers in pursuit of the elusive goal of clear, concise, and unambiguous MIB documents.

The new data types are: OwnerString and EntryStatus.

2.3. Structure of MIB

The objects are arranged into the following groups:

- ethernet statistics - history control - ethernet history - alarm

- host - hostTopN - matrix - filter

- packet capture - event

These groups are the basic unit of conformance. If a remote monitoring device implements a group, then it must implement all objects in that group. For example, a managed agent that implements the host group must implement the hostControlTable, the hostTable and the hostTimeTable.

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All groups in this MIB are optional. Implementations of this MIB must also implement the system and interfaces group of MIB-II [6].

MIB-II may also mandate the implementation of additional groups.

These groups are defined to provide a means of assigning object

identifiers, and to provide a method for managed agents to know which objects they must implement.

2.3.1. The Ethernet Statistics Group

The ethernet statistics group contains statistics measured by the probe for each monitored Ethernet interface on this device. This group consists of the etherStatsTable. In the future other groups will be defined for other media types including Token Ring and FDDI.

These groups should follow the same model as the ethernet statistics group.

2.3.2. The History Control Group

The history control group controls the periodic statistical sampling of data from various types of networks. This group consists of the historyControlTable.

2.3.3. The Ethernet History Group

The ethernet history group records periodic statistical samples from an ethernet network and stores them for later retrieval. This group consists of the etherHistoryTable. In the future, other groups will be defined for other media types including Token Ring and FDDI.

2.3.4. The Alarm Group

The alarm group periodically takes statistical samples from variables in the probe and compares them to previously configured thresholds.

If the monitored variable crosses a threshold, an event is generated.

A hysteresis mechanism is implemented to limit the generation of alarms. This group consists of the alarmTable and requires the implementation of the event group.

2.3.5. The Host Group

The host group contains statistics associated with each host

discovered on the network. This group discovers hosts on the network by keeping a list of source and destination MAC Addresses seen in good packets promiscuously received from the network. This group consists of the hostControlTable, the hostTable, and the

hostTimeTable.

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2.3.6. The HostTopN Group

The hostTopN group is used to prepare reports that describe the hosts that top a list ordered by one of their statistics. The available statistics are samples of one of their base statistics over an

interval specified by the management station. Thus, these statistics are rate based. The management station also selects how many such hosts are reported. This group consists of the hostTopNControlTable and the hostTopNTable, and requires the implementation of the host group.

2.3.7. The Matrix Group

The matrix group stores statistics for conversations between sets of two addresses. As the device detects a new conversation, it creates a new entry in its tables. This group consists of the

matrixControlTable, the matrixSDTable and the matrixDSTable.

2.3.8. The Filter Group

The filter group allows packets to be matched by a filter equation.

These matched packets form a data stream that may be captured or may generate events. This group consists of the filterTable and the channelTable.

2.3.9. The Packet Capture Group

The Packet Capture group allows packets to be captured after they flow through a channel. This group consists of the

bufferControlTable and the captureBufferTable, and requires the implementation of the filter group.

2.3.10. The Event Group

The event group controls the generation and notification of events from this device. This group consists of the eventTable and the logTable.

3. Control of Remote Network Monitoring Devices

Due to the complex nature of the available functions in these

devices, the functions often need user configuration. In many cases, the function requires parameters to be set up for a data collection operation. The operation can proceed only after these parameters are fully set up.

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Many functional groups in this MIB have one or more tables in which to set up control parameters, and one or more data tables in which to place the results of the operation. The control tables are typically read-write in nature, while the data tables are typically read-only.

Because the parameters in the control table often describe resulting data in the data table, many of the parameters can be modified only when the control entry is invalid. Thus, the method for modifying these parameters is to invalidate the control entry, causing its deletion and the deletion of any associated data entries, and then create a new control entry with the proper parameters. Deleting the control entry also gives a convenient method for reclaiming the resources used by the associated data.

Some objects in this MIB provide a mechanism to execute an action on the remote monitoring device. These objects may execute an action as a result of a change in the state of the object. For those objects in this MIB, a request to set an object to the same value as it currently holds would thus cause no action to occur.

To facilitate control by multiple managers, resources have to be shared among the managers. These resources are typically the memory and computation resources that a function requires.

3.1. Resource Sharing Among Multiple Management Stations

When multiple management stations wish to use functions that compete for a finite amount of resources on a device, a method to facilitate this sharing of resources is required. Potential conflicts include:

o Two management stations wish to simultaneously use resources that together would exceed the capability of the device.

o A management station uses a significant amount of resources for a long period of time.

o A management station uses resources and then crashes, forgetting to free the resources so others may

use them.

A mechanism is provided for each management station initiated function in this MIB to avoid these conflicts and to help resolve them when they occur. Each function has a label identifying the initiator (owner) of the function. This label is set by the initiator to provide for the following possibilities:

o A management station may recognize resources it owns and no longer needs.

o A network operator can find the management station that owns the resource and negotiate for it to be freed.

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o A network operator may decide to unilaterally free resources another network operator has reserved.

o Upon initialization, a management station may recognize resources it had reserved in the past. With this

information it may free the resources if it no longer needs them.

Management stations and probes should support any format of the owner string dictated by the local policy of the organization. It is

suggested that this name contain one or more of the following: IP address, management station name, network manager’s name, location, or phone number. This information will help users to share the resources more effectively.

There is often default functionality that the device or the

administrator of the probe (often the network administrator) wishes to set up. The resources associated with this functionality are then owned by the device itself or by the network administrator, and are intended to be long-lived. In this case, the device or the

administrator will set the relevant owner object to a string starting with ’monitor’. Indiscriminate modification of the monitor-owned configuration by network management stations is discouraged. In fact, a network management station should only modify these objects under the direction of the administrator of the probe.

Resources on a probe are scarce and are typically allocated when control rows are created by an application. Since many applications may be using a probe simultaneously, indiscriminate allocation of resources to particular applications is very likely to cause resource shortages in the probe.

When a network management station wishes to utilize a function in a monitor, it is encouraged to first scan the control table of that function to find an instance with similar parameters to share. This is especially true for those instances owned by the monitor, which can be assumed to change infrequently. If a management station decides to share an instance owned by another management station, it should understand that the management station that owns the instance may indiscriminately modify or delete it.

It should be noted that a management application should have the most trust in a monitor-owned row because it should be changed very

infrequently. A row owned by the management application is less long-lived because a network administrator is more likely to re- assign resources from a row that is in use by one user than from a monitor-owned row that is potentially in use by many users. A row owned by another application would be even less long-lived because the other application may delete or modify that row completely at its

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discretion.

3.2. Row Addition Among Multiple Management Stations

The addition of new rows is achieved using the method described in RFC 1212 [9]. In this MIB, rows are often added to a table in order to configure a function. This configuration usually involves

parameters that control the operation of the function. The agent must check these parameters to make sure they are appropriate given restrictions defined in this MIB as well as any implementation specific restrictions such as lack of resources. The agent

implementor may be confused as to when to check these parameters and when to signal to the management station that the parameters are invalid. There are two opportunities:

o When the management station sets each parameter object.

o When the management station sets the entry status object to valid.

If the latter is chosen, it would be unclear to the management station which of the several parameters was invalid and caused the badValue error to be emitted. Thus, wherever possible, the

implementor should choose the former as it will provide more information to the management station.

A problem can arise when multiple management stations attempt to set configuration information simultaneously using SNMP. When this involves the addition of a new conceptual row in the same control table, the managers may collide, attempting to create the same entry.

To guard against these collisions, each such control entry contains a status object with special semantics that help to arbitrate among the managers. If an attempt is made with the row addition mechanism to create such a status object and that object already exists, an error is returned. When more than one manager simultaneously attempts to create the same conceptual row, only the first will succeed. The others will receive an error.

When a manager wishes to create a new control entry, it needs to choose an index for that row. It may choose this index in a variety of ways, hopefully minimizing the chances that the index is in use by another manager. If the index is in use, the mechanism mentioned previously will guard against collisions. Examples of schemes to choose index values include random selection or scanning the control table looking for the first unused index. Because index values may be any valid value in the range and they are chosen by the manager, the agent must allow a row to be created with any unused index value if it has the resources to create a new row.

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Some tables in this MIB reference other tables within this MIB. When creating or deleting entries in these tables, it is generally

allowable for dangling references to exist. There is no defined order for creating or deleting entries in these tables.

4. Conventions

The following conventions are used throughout the RMON MIB and its companion documents.

Good Packets

Good packets are error-free packets that have a valid frame length.

For example, on Ethernet, good packets are error-free packets that are between 64 octets long and 1518 octets long. They follow the form defined in IEEE 802.3 section 3.2.all.

Bad Packets

Bad packets are packets that have proper framing and are therefore recognized as packets, but contain errors within the packet or have an invalid length. For example, on Ethernet, bad packets have a valid preamble and SFD, but have a bad CRC, or are either shorter than 64 octets or longer than 1518 octets.

5. Definitions

RMON-MIB DEFINITIONS ::= BEGIN IMPORTS

Counter FROM RFC1155-SMI DisplayString FROM RFC1158-MIB mib-2 FROM RFC1213-MIB OBJECT-TYPE FROM RFC-1212 TRAP-TYPE FROM RFC-1215;

-- Remote Network Monitoring MIB

rmon OBJECT IDENTIFIER ::= { mib-2 16 }

-- textual conventions

OwnerString ::= DisplayString

-- This data type is used to model an administratively -- assigned name of the owner of a resource. This -- information is taken from the NVT ASCII character -- set. It is suggested that this name contain one or

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-- more of the following: IP address, management station -- name, network manager’s name, location, or phone -- number.

-- In some cases the agent itself will be the owner of -- an entry. In these cases, this string shall be set -- to a string starting with ’monitor’.

--

-- SNMP access control is articulated entirely in terms -- of the contents of MIB views; access to a particular -- SNMP object instance depends only upon its presence -- or absence in a particular MIB view and never upon -- its value or the value of related object instances.

-- Thus, objects of this type afford resolution of -- resource contention only among cooperating managers;

-- they realize no access control function with respect -- to uncooperative parties.

--

-- By convention, objects with this syntax are declared as -- having

--

-- SIZE (0..127) EntryStatus ::= INTEGER { valid(1),

createRequest(2), underCreation(3), invalid(4)

}

-- The status of a table entry.

--

-- Setting this object to the value invalid(4) has the -- effect of invalidating the corresponding entry.

-- That is, it effectively disassociates the mapping -- identified with said entry.

-- It is an implementation-specific matter as to whether -- the agent removes an invalidated entry from the table.

-- Accordingly, management stations must be prepared to -- receive tabular information from agents that

-- corresponds to entries currently not in use. Proper -- interpretation of such entries requires examination -- of the relevant EntryStatus object.

--

-- An existing instance of this object cannot be set to -- createRequest(2). This object may only be set to -- createRequest(2) when this instance is created. When -- this object is created, the agent may wish to create -- supplemental object instances with default values -- to complete a conceptual row in this table. Because

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-- the creation of these default objects is entirely at -- the option of the agent, the manager must not assume -- that any will be created, but may make use of any that -- are created. Immediately after completing the create -- operation, the agent must set this object to

-- underCreation(3).

--

-- When in the underCreation(3) state, an entry is -- allowed to exist in a possibly incomplete, possibly -- inconsistent state, usually to allow it to be

-- modified in mutiple PDUs. When in this state, an -- entry is not fully active. Entries shall exist in -- the underCreation(3) state until the management -- station is finished configuring the entry and sets -- this object to valid(1) or aborts, setting this -- object to invalid(4). If the agent determines that -- an entry has been in the underCreation(3) state for -- an abnormally long time, it may decide that the -- management station has crashed. If the agent makes -- this decision, it may set this object to invalid(4) -- to reclaim the entry. A prudent agent will

-- understand that the management station may need to -- wait for human input and will allow for that

-- possibility in its determination of this abnormally -- long period.

--

-- An entry in the valid(1) state is fully configured and -- consistent and fully represents the configuration or -- operation such a row is intended to represent. For -- example, it could be a statistical function that is -- configured and active, or a filter that is available -- in the list of filters processed by the packet capture -- process.

--

-- A manager is restricted to changing the state of an -- entry in the following ways:

--

-- create under

-- To: valid Request Creation invalid -- From:

-- valid OK NO OK OK -- createRequest N/A N/A N/A N/A -- underCreation OK NO OK OK -- invalid NO NO NO OK -- nonExistent NO OK NO OK --

-- In the table above, it is not applicable to move the -- state from the createRequest state to any other

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-- state because the manager will never find the -- variable in that state. The nonExistent state is -- not a value of the enumeration, rather it means that -- the entryStatus variable does not exist at all.

--

-- An agent may allow an entryStatus variable to change -- state in additional ways, so long as the semantics -- of the states are followed. This allowance is made -- to ease the implementation of the agent and is made -- despite the fact that managers should never

-- excercise these additional state transitions.

statistics OBJECT IDENTIFIER ::= { rmon 1 } history OBJECT IDENTIFIER ::= { rmon 2 } alarm OBJECT IDENTIFIER ::= { rmon 3 } hosts OBJECT IDENTIFIER ::= { rmon 4 } hostTopN OBJECT IDENTIFIER ::= { rmon 5 } matrix OBJECT IDENTIFIER ::= { rmon 6 } filter OBJECT IDENTIFIER ::= { rmon 7 } capture OBJECT IDENTIFIER ::= { rmon 8 } event OBJECT IDENTIFIER ::= { rmon 9 }

-- The Ethernet Statistics Group --

-- Implementation of the Ethernet Statistics group is -- optional.

--

-- The ethernet statistics group contains statistics -- measured by the probe for each monitored interface on -- this device. These statistics take the form of free -- running counters that start from zero when a valid entry -- is created.

--

-- This group currently has statistics defined only for -- Ethernet interfaces. Each etherStatsEntry contains -- statistics for one Ethernet interface. The probe must -- create one etherStats entry for each monitored Ethernet -- interface on the device.

etherStatsTable OBJECT-TYPE

SYNTAX SEQUENCE OF EtherStatsEntry ACCESS not-accessible

STATUS mandatory DESCRIPTION

"A list of Ethernet statistics entries."

::= { statistics 1 }

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etherStatsEntry OBJECT-TYPE SYNTAX EtherStatsEntry ACCESS not-accessible STATUS mandatory DESCRIPTION

"A collection of statistics kept for a particular Ethernet interface. As an example, an instance of the etherStatsPkts object might be named etherStatsPkts.1"

INDEX { etherStatsIndex } ::= { etherStatsTable 1 } EtherStatsEntry ::= SEQUENCE {

etherStatsIndex INTEGER (1..65535), etherStatsDataSource OBJECT IDENTIFIER, etherStatsDropEvents Counter,

etherStatsOctets Counter, etherStatsPkts Counter, etherStatsBroadcastPkts Counter, etherStatsMulticastPkts Counter, etherStatsCRCAlignErrors Counter, etherStatsUndersizePkts Counter, etherStatsOversizePkts Counter, etherStatsFragments Counter, etherStatsJabbers Counter, etherStatsCollisions Counter, etherStatsPkts64Octets Counter, etherStatsPkts65to127Octets Counter, etherStatsPkts128to255Octets Counter, etherStatsPkts256to511Octets Counter, etherStatsPkts512to1023Octets Counter, etherStatsPkts1024to1518Octets Counter, etherStatsOwner OwnerString, etherStatsStatus EntryStatus }

etherStatsIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only

"The value of this object uniquely identifies this etherStats entry."

::= { etherStatsEntry 1 } etherStatsDataSource OBJECT-TYPE SYNTAX OBJECT IDENTIFIER ACCESS read-write

STATUS mandatory

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DESCRIPTION

"This object identifies the source of the data that this etherStats entry is configured to analyze. This source can be any ethernet interface on this device.

In order to identify a particular interface, this object shall identify the instance of the ifIndex object, defined in RFC 1213 and RFC 1573 [4,6], for the desired interface. For example, if an entry were to receive data from interface #1, this object would be set to ifIndex.1.

The statistics in this group reflect all packets on the local network segment attached to the identified interface.

An agent may or may not be able to tell if

fundamental changes to the media of the interface have occurred and necessitate an invalidation of this entry. For example, a hot-pluggable ethernet card could be pulled out and replaced by a

token-ring card. In such a case, if the agent has such knowledge of the change, it is recommended that it invalidate this entry.

This object may not be modified if the associated etherStatsStatus object is equal to valid(1)."

::= { etherStatsEntry 2 } etherStatsDropEvents OBJECT-TYPE SYNTAX Counter

ACCESS read-only STATUS mandatory DESCRIPTION

"The total number of events in which packets

were dropped by the probe due to lack of resources.

Note that this number is not necessarily the number of packets dropped; it is just the number of times this condition has been detected."

::= { etherStatsEntry 3 } etherStatsOctets OBJECT-TYPE SYNTAX Counter

"The total number of octets of data (including those in bad packets) received on the

network (excluding framing bits but including

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FCS octets).

This object can be used as a reasonable estimate of ethernet utilization. If greater precision is desired, the etherStatsPkts and etherStatsOctets objects should be sampled before and after a common interval. The differences in the sampled values are Pkts and Octets, respectively, and the number of seconds in the interval is Interval. These values are used to calculate the Utilization as follows:

Pkts * (9.6 + 6.4) + (Octets * .8) Utilization = --- Interval * 10,000

The result of this equation is the value Utilization which is the percent utilization of the ethernet segment on a scale of 0 to 100 percent."

::= { etherStatsEntry 4 } etherStatsPkts OBJECT-TYPE SYNTAX Counter

"The total number of packets (including bad packets, broadcast packets, and multicast packets) received."

::= { etherStatsEntry 5 }

etherStatsBroadcastPkts OBJECT-TYPE SYNTAX Counter

"The total number of good packets received that were directed to the broadcast address. Note that this does not include multicast packets."

etherStatsMulticastPkts OBJECT-TYPE SYNTAX Counter

"The total number of good packets received that were directed to a multicast address. Note that this number does not include packets directed to the broadcast address."

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etherStatsCRCAlignErrors OBJECT-TYPE SYNTAX Counter

"The total number of packets received that had a length (excluding framing bits, but including FCS octets) of between 64 and 1518 octets, inclusive, but but had either a bad Frame Check Sequence (FCS) with an integral number of octets (FCS Error) or a bad FCS with a non-integral number of octets (Alignment Error)."

etherStatsUndersizePkts OBJECT-TYPE SYNTAX Counter

"The total number of packets received that were less than 64 octets long (excluding framing bits, but including FCS octets) and were otherwise well formed."

::= { etherStatsEntry 9 } etherStatsOversizePkts OBJECT-TYPE SYNTAX Counter

"The total number of packets received that were longer than 1518 octets (excluding framing bits, but including FCS octets) and were otherwise well formed."

::= { etherStatsEntry 10 } etherStatsFragments OBJECT-TYPE SYNTAX Counter

"The total number of packets received that were less than 64 octets in length (excluding framing bits but including FCS octets) and had either a bad Frame Check Sequence (FCS) with an integral number of octets (FCS Error) or a bad FCS with a non-integral

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number of octets (Alignment Error).

Note that it is entirely normal for

etherStatsFragments to increment. This is because it counts both runts (which are normal occurrences due to collisions) and noise hits."

::= { etherStatsEntry 11 } etherStatsJabbers OBJECT-TYPE SYNTAX Counter

"The total number of packets received that were longer than 1518 octets (excluding framing bits, but including FCS octets), and had either a bad Frame Check Sequence (FCS) with an integral number of octets (FCS Error) or a bad FCS with a

non-integral number of octets (Alignment Error).

Note that this definition of jabber is different than the definition in IEEE-802.3 section 8.2.1.5 (10BASE5) and section 10.3.1.4 (10BASE2). These documents define jabber as the condition where any packet exceeds 20 ms. The allowed range to detect jabber is between 20 ms and 150 ms."

::= { etherStatsEntry 12 } etherStatsCollisions OBJECT-TYPE SYNTAX Counter

"The best estimate of the total number of collisions on this Ethernet segment.

The value returned will depend on the location of the RMON probe. Section 8.2.1.3 (10BASE-5) and section 10.3.1.3 (10BASE-2) of IEEE standard 802.3 states that a station must detect a collision, in the receive mode, if three or more stations are transmitting simultaneously. A repeater port must detect a collision when two or more stations are transmitting simultaneously. Thus a probe placed on a repeater port could record more collisions than a probe connected to a station on the same segment would.

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Probe location plays a much smaller role when considering 10BASE-T. 14.2.1.4 (10BASE-T) of IEEE standard 802.3 defines a collision as the

simultaneous presence of signals on the DO and RD circuits (transmitting and receiving at the same time). A 10BASE-T station can only detect

collisions when it is transmitting. Thus probes placed on a station and a repeater, should report the same number of collisions.

Note also that an RMON probe inside a repeater should ideally report collisions between the repeater and one or more other hosts (transmit collisions as defined by IEEE 802.3k) plus receiver collisions observed on any coax segments to which the repeater is connected."

::= { etherStatsEntry 13 } etherStatsPkts64Octets OBJECT-TYPE SYNTAX Counter

"The total number of packets (including bad packets) received that were 64 octets in length (excluding framing bits but including FCS octets)."

etherStatsPkts65to127Octets OBJECT-TYPE SYNTAX Counter

"The total number of packets (including bad packets) received that were between

65 and 127 octets in length inclusive

(excluding framing bits but including FCS octets)."

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::= { etherStatsEntry 19 } etherStatsOwner OBJECT-TYPE SYNTAX OwnerString ACCESS read-write STATUS mandatory DESCRIPTION

"The entity that configured this entry and is therefore using the resources assigned to it."

::= { etherStatsEntry 20 } etherStatsStatus OBJECT-TYPE SYNTAX EntryStatus

ACCESS read-write STATUS mandatory

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DESCRIPTION

"The status of this etherStats entry."

-- The History Control Group

-- Implementation of the History Control group is optional.

--

-- The history control group controls the periodic statistical -- sampling of data from various types of networks. The

-- historyControlTable stores configuration entries that each -- define an interface, polling period, and other parameters.

-- Once samples are taken, their data is stored in an entry -- in a media-specific table. Each such entry defines one -- sample, and is associated with the historyControlEntry that -- caused the sample to be taken. Each counter in the

-- etherHistoryEntry counts the same event as its -- similarly-named counterpart in the etherStatsEntry, -- except that each value here is a cumulative sum during a -- sampling period.

--

-- If the probe keeps track of the time of day, it should -- start the first sample of the history at a time such that -- when the next hour of the day begins, a sample is

-- started at that instant. This tends to make more

-- user-friendly reports, and enables comparison of reports -- from different probes that have relatively accurate time -- of day.

--

-- The probe is encouraged to add two history control entries -- per monitored interface upon initialization that describe -- a short term and a long term polling period. Suggested -- parameters are 30 seconds for the short term polling period -- and 30 minutes for the long term period.

historyControlTable OBJECT-TYPE

SYNTAX SEQUENCE OF HistoryControlEntry ACCESS not-accessible

"A list of history control entries."

::= { history 1 }

historyControlEntry OBJECT-TYPE SYNTAX HistoryControlEntry ACCESS not-accessible STATUS mandatory

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DESCRIPTION

"A list of parameters that set up a periodic sampling of statistics. As an example, an instance of the historyControlInterval object might be named historyControlInterval.2"

INDEX { historyControlIndex } ::= { historyControlTable 1 } HistoryControlEntry ::= SEQUENCE {

historyControlIndex INTEGER (1..65535), historyControlDataSource OBJECT IDENTIFIER, historyControlBucketsRequested INTEGER (1..65535), historyControlBucketsGranted INTEGER (1..65535), historyControlInterval INTEGER (1..3600), historyControlOwner OwnerString,

historyControlStatus EntryStatus }

historyControlIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only

"An index that uniquely identifies an entry in the historyControl table. Each such entry defines a set of samples at a particular interval for an interface on the device."

::= { historyControlEntry 1 } historyControlDataSource OBJECT-TYPE SYNTAX OBJECT IDENTIFIER

ACCESS read-write STATUS mandatory DESCRIPTION

"This object identifies the source of the data for which historical data was collected and

placed in a media-specific table on behalf of this historyControlEntry. This source can be any

interface on this device. In order to identify a particular interface, this object shall identify the instance of the ifIndex object, defined

in RFC 1213 and RFC 1573 [4,6], for the desired interface. For example, if an entry were to receive data from interface #1, this object would be set to ifIndex.1.

The statistics in this group reflect all packets on the local network segment attached to the

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identified interface.

An agent may or may not be able to tell if fundamental changes to the media of the interface have occurred and necessitate an invalidation of this entry. For example, a hot-pluggable ethernet card could be pulled out and replaced by a token-ring card. In such a case, if the agent has such knowledge of the change, it is recommended that it invalidate this entry.

This object may not be modified if the associated historyControlStatus object is equal to valid(1)."

::= { historyControlEntry 2 }

historyControlBucketsRequested OBJECT-TYPE SYNTAX INTEGER (1..65535)

"The requested number of discrete time intervals over which data is to be saved in the part of the media-specific table associated with this

historyControlEntry.

When this object is created or modified, the probe should set historyControlBucketsGranted as closely to this object as is possible for the particular probe implementation and available resources."

DEFVAL { 50 }

historyControlBucketsGranted OBJECT-TYPE SYNTAX INTEGER (1..65535)

"The number of discrete sampling intervals over which data shall be saved in the part of the media-specific table associated with this historyControlEntry.

When the associated historyControlBucketsRequested object is created or modified, the probe

should set this object as closely to the requested value as is possible for the particular

probe implementation and available resources. The probe must not lower this value except as a result

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of a modification to the associated historyControlBucketsRequested object.

There will be times when the actual number of buckets associated with this entry is less than the value of this object. In this case, at the end of each sampling interval, a new bucket will be added to the media-specific table.

When the number of buckets reaches the value of this object and a new bucket is to be added to the media-specific table, the oldest bucket associated with this historyControlEntry shall be deleted by the agent so that the new bucket can be added.

When the value of this object changes to a value less than the current value, entries are deleted

from the media-specific table associated with this historyControlEntry. Enough of the oldest of these entries shall be deleted by the agent so that their number remains less than or equal to the new value of this object.

When the value of this object changes to a value greater than the current value, the number of

associated media- specific entries may be allowed to grow."

::= { historyControlEntry 4 } historyControlInterval OBJECT-TYPE SYNTAX INTEGER (1..3600)

"The interval in seconds over which the data is sampled for each bucket in the part of the media-specific table associated with this historyControlEntry. This interval can

be set to any number of seconds between 1 and 3600 (1 hour).

Because the counters in a bucket may overflow at their maximum value with no indication, a prudent manager will take into account the possibility of overflow in any of the associated counters. It is important to consider the minimum time in which any counter could overflow on a particular media type and set the historyControlInterval object to a value less

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than this interval. This is typically most important for the ’octets’ counter in any

media-specific table. For example, on an Ethernet network, the etherHistoryOctets counter could

overflow in about one hour at the Ethernet’s maximum utilization.

This object may not be modified if the associated historyControlStatus object is equal to valid(1)."

DEFVAL { 1800 }

::= { historyControlEntry 5 } historyControlOwner OBJECT-TYPE SYNTAX OwnerString

"The entity that configured this entry and is therefore using the resources assigned to it."

::= { historyControlEntry 6 } historyControlStatus OBJECT-TYPE SYNTAX EntryStatus

"The status of this historyControl entry.

Each instance of the media-specific table associated with this historyControlEntry will be deleted by the agent if this historyControlEntry is not equal to valid(1)."

-- The Ethernet History Group

-- Implementation of the Ethernet History group is optional.

--

-- The Ethernet History group records periodic

-- statistical samples from a network and stores them -- for later retrieval. Once samples are taken, their -- data is stored in an entry in a media-specific -- table. Each such entry defines one sample, and is -- associated with the historyControlEntry that caused -- the sample to be taken. This group defines the -- etherHistoryTable, for Ethernet networks.

--

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etherHistoryTable OBJECT-TYPE

SYNTAX SEQUENCE OF EtherHistoryEntry ACCESS not-accessible

"A list of Ethernet history entries."

::= { history 2 }

etherHistoryEntry OBJECT-TYPE SYNTAX EtherHistoryEntry ACCESS not-accessible STATUS mandatory DESCRIPTION

"An historical sample of Ethernet statistics on a particular Ethernet interface. This sample is

associated with the historyControlEntry which set up the parameters for a regular collection of these samples. As an example, an instance of the etherHistoryPkts object might be named etherHistoryPkts.2.89"

INDEX { etherHistoryIndex , etherHistorySampleIndex } ::= { etherHistoryTable 1 }

EtherHistoryEntry ::= SEQUENCE {

etherHistoryIndex INTEGER (1..65535), etherHistorySampleIndex INTEGER (1..2147483647), etherHistoryIntervalStart TimeTicks,

etherHistoryDropEvents Counter, etherHistoryOctets Counter, etherHistoryPkts Counter, etherHistoryBroadcastPkts Counter, etherHistoryMulticastPkts Counter, etherHistoryCRCAlignErrors Counter, etherHistoryUndersizePkts Counter, etherHistoryOversizePkts Counter, etherHistoryFragments Counter, etherHistoryJabbers Counter, etherHistoryCollisions Counter,

etherHistoryUtilization INTEGER (0..10000) }

etherHistoryIndex OBJECT-TYPE SYNTAX INTEGER (1..65535) ACCESS read-only

"The history of which this entry is a part. The history identified by a particular value of this

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index is the same history as identified by the same value of historyControlIndex."

::= { etherHistoryEntry 1 } etherHistorySampleIndex OBJECT-TYPE SYNTAX INTEGER (1..2147483647) ACCESS read-only

"An index that uniquely identifies the particular sample this entry represents among all samples associated with the same historyControlEntry.

This index starts at 1 and increases by one as each new sample is taken."

::= { etherHistoryEntry 2 }

etherHistoryIntervalStart OBJECT-TYPE SYNTAX TimeTicks

"The value of sysUpTime at the start of the interval over which this sample was measured. If the probe keeps track of the time of day, it should start the first sample of the history at a time such that when the next hour of the day begins, a sample is started at that instant. Note that following this rule may require the probe to delay collecting the first sample of the history, as each sample must be of the same interval. Also note that the sample which is currently being collected is not accessible in this table until the end of its interval."

::= { etherHistoryEntry 3 } etherHistoryDropEvents OBJECT-TYPE SYNTAX Counter

"The total number of events in which packets

were dropped by the probe due to lack of resources during this sampling interval. Note that this number is not necessarily the number of packets dropped, it is just the number of times this condition has been detected."

::= { etherHistoryEntry 4 } etherHistoryOctets OBJECT-TYPE

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SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION

"The total number of octets of data (including those in bad packets) received on the

network (excluding framing bits but including FCS octets)."

::= { etherHistoryEntry 5 } etherHistoryPkts OBJECT-TYPE SYNTAX Counter

"The number of packets (including bad packets) received during this sampling interval."

etherHistoryBroadcastPkts OBJECT-TYPE SYNTAX Counter

"The number of good packets received during this sampling interval that were directed to the broadcast address."

etherHistoryMulticastPkts OBJECT-TYPE SYNTAX Counter

"The number of good packets received during this sampling interval that were directed to a

multicast address. Note that this number does not include packets addressed to the broadcast address."

etherHistoryCRCAlignErrors OBJECT-TYPE SYNTAX Counter

"The number of packets received during this sampling interval that had a length (excluding framing bits but including FCS octets) between 64 and 1518

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octets, inclusive, but had either a bad Frame Check Sequence (FCS) with an integral number of octets (FCS Error) or a bad FCS with a non-integral number of octets (Alignment Error)."

etherHistoryUndersizePkts OBJECT-TYPE SYNTAX Counter

"The number of packets received during this sampling interval that were less than 64 octets long (excluding framing bits but including FCS octets) and were otherwise well formed."

::= { etherHistoryEntry 10 } etherHistoryOversizePkts OBJECT-TYPE SYNTAX Counter

"The number of packets received during this sampling interval that were longer than 1518 octets (excluding framing bits but including FCS octets) but were otherwise well formed."

::= { etherHistoryEntry 11 } etherHistoryFragments OBJECT-TYPE SYNTAX Counter

"The total number of packets received during this sampling interval that were less than 64 octets in length (excluding framing bits but including FCS octets) had either a bad Frame Check Sequence (FCS) with an integral number of octets (FCS Error) or a bad FCS with a non-integral number of octets (Alignment Error).

Note that it is entirely normal for

etherHistoryFragments to increment. This is because it counts both runts (which are normal occurrences due to collisions) and noise hits."

::= { etherHistoryEntry 12 } etherHistoryJabbers OBJECT-TYPE

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SYNTAX Counter ACCESS read-only STATUS mandatory DESCRIPTION

"The number of packets received during this

sampling interval that were longer than 1518 octets (excluding framing bits but including FCS octets), and had either a bad Frame Check Sequence (FCS) with an integral number of octets (FCS Error) or a bad FCS with a non-integral number of octets (Alignment Error).

Note that this definition of jabber is different than the definition in IEEE-802.3 section 8.2.1.5 (10BASE5) and section 10.3.1.4 (10BASE2). These documents define jabber as the condition where any packet exceeds 20 ms. The allowed range to detect jabber is between 20 ms and 150 ms."

::= { etherHistoryEntry 13 } etherHistoryCollisions OBJECT-TYPE SYNTAX Counter

"The best estimate of the total number of collisions on this Ethernet segment during this sampling

interval.

The value returned will depend on the location of the RMON probe. Section 8.2.1.3 (10BASE-5) and section 10.3.1.3 (10BASE-2) of IEEE standard 802.3 states that a station must detect a collision, in the receive mode, if three or more stations are transmitting simultaneously. A repeater port must detect a collision when two or more stations are transmitting simultaneously. Thus a probe placed on a repeater port could record more collisions than a probe connected to a station on the same segment would.

Probe location plays a much smaller role when considering 10BASE-T. 14.2.1.4 (10BASE-T) of IEEE standard 802.3 defines a collision as the

simultaneous presence of signals on the DO and RD circuits (transmitting and receiving at the same time). A 10BASE-T station can only detect

collisions when it is transmitting. Thus probes

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placed on a station and a repeater, should report the same number of collisions.

Note also that an RMON probe inside a repeater should ideally report collisions between the repeater and one or more other hosts (transmit collisions as defined by IEEE 802.3k) plus receiver collisions observed on any coax segments to which the repeater is connected."

::= { etherHistoryEntry 14 } etherHistoryUtilization OBJECT-TYPE SYNTAX INTEGER (0..10000)

"The best estimate of the mean physical layer network utilization on this interface during this sampling interval, in hundredths of a percent."

-- The Alarm Group

-- Implementation of the Alarm group is optional.

--

-- The Alarm Group requires the implementation of the Event -- group.

--

-- The Alarm group periodically takes

-- statistical samples from variables in the probe and -- compares them to thresholds that have been

-- configured. The alarm table stores configuration -- entries that each define a variable, polling period, -- and threshold parameters. If a sample is found to -- cross the threshold values, an event is generated.

-- Only variables that resolve to an ASN.1 primitive -- type of INTEGER (INTEGER, Counter, Gauge, or -- TimeTicks) may be monitored in this way.

--

-- This function has a hysteresis mechanism to limit -- the generation of events. This mechanism generates -- one event as a threshold is crossed in the

-- appropriate direction. No more events are generated -- for that threshold until the opposite threshold is -- crossed.

--

-- In the case of a sampling a deltaValue, a probe may

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-- implement this mechanism with more precision if it -- takes a delta sample twice per period, each time -- comparing the sum of the latest two samples to the -- threshold. This allows the detection of threshold -- crossings that span the sampling boundary. Note -- that this does not require any special configuration -- of the threshold value. It is suggested that probes -- implement this more precise algorithm.

alarmTable OBJECT-TYPE

SYNTAX SEQUENCE OF AlarmEntry ACCESS not-accessible

"A list of alarm entries."

::= { alarm 1 } alarmEntry OBJECT-TYPE SYNTAX AlarmEntry ACCESS not-accessible STATUS mandatory DESCRIPTION

"A list of parameters that set up a periodic checking for alarm conditions. For example, an instance of the alarmValue object might be named alarmValue.8"

INDEX { alarmIndex } ::= { alarmTable 1 } AlarmEntry ::= SEQUENCE {

alarmIndex INTEGER (1..65535), alarmInterval INTEGER,

alarmVariable OBJECT IDENTIFIER, alarmSampleType INTEGER,

alarmValue INTEGER, alarmStartupAlarm INTEGER, alarmRisingThreshold INTEGER, alarmFallingThreshold INTEGER,

alarmRisingEventIndex INTEGER (0..65535), alarmFallingEventIndex INTEGER (0..65535), alarmOwner OwnerString,

alarmStatus EntryStatus }

alarmIndex OBJECT-TYPE

SYNTAX INTEGER (1..65535) ACCESS read-only

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"An index that uniquely identifies an entry in the alarm table. Each such entry defines a

diagnostic sample at a particular interval for an object on the device."

::= { alarmEntry 1 } alarmInterval OBJECT-TYPE SYNTAX INTEGER

"The interval in seconds over which the data is sampled and compared with the rising and falling thresholds. When setting this variable, care should be taken in the case of deltaValue

sampling - the interval should be set short enough that the sampled variable is very unlikely to increase or decrease by more than 2^31 - 1 during a single sampling interval.

This object may not be modified if the associated alarmStatus object is equal to valid(1)."

::= { alarmEntry 2 } alarmVariable OBJECT-TYPE SYNTAX OBJECT IDENTIFIER ACCESS read-write

"The object identifier of the particular variable to be sampled. Only variables that resolve to an ASN.1 primitive type of INTEGER (INTEGER, Counter, Gauge, or TimeTicks) may be sampled.

Because SNMP access control is articulated entirely in terms of the contents of MIB views, no access control mechanism exists that can restrict the value of this object to identify only those objects that exist in a particular MIB view. Because there is thus no acceptable means of restricting the read access that could be obtained through the alarm mechanism, the probe must only grant write access to this object in those views that have read access to all objects on the probe.

During a set operation, if the supplied variable name is not available in the selected MIB view, a badValue error must be returned. If at any time the

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variable name of an established alarmEntry is no longer available in the selected MIB view, the probe must change the status of this alarmEntry to

invalid(4).

::= { alarmEntry 3 } alarmSampleType OBJECT-TYPE SYNTAX INTEGER {

absoluteValue(1), deltaValue(2) }

"The method of sampling the selected variable and calculating the value to be compared against the thresholds. If the value of this object is

absoluteValue(1), the value of the selected variable will be compared directly with the thresholds at the end of the sampling interval. If the value of this object is deltaValue(2), the value of the selected variable at the last sample will be subtracted from the current value, and the difference compared with the thresholds.

::= { alarmEntry 4 } alarmValue OBJECT-TYPE SYNTAX INTEGER ACCESS read-only STATUS mandatory DESCRIPTION

"The value of the statistic during the last sampling period. For example, if the sample type is

deltaValue, this value will be the difference

between the samples at the beginning and end of the period. If the sample type is absoluteValue, this value will be the sampled value at the end of the period.

This is the value that is compared with the rising and falling thresholds.

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The value during the current sampling period is not made available until the period is completed and will remain available until the next period completes."

::= { alarmEntry 5 } alarmStartupAlarm OBJECT-TYPE SYNTAX INTEGER {

risingAlarm(1), fallingAlarm(2),

risingOrFallingAlarm(3) }

"The alarm that may be sent when this entry is first set to valid. If the first sample after this entry becomes valid is greater than or equal to the

risingThreshold and alarmStartupAlarm is equal to risingAlarm(1) or risingOrFallingAlarm(3), then a single rising alarm will be generated. If the first sample after this entry becomes valid is less than or equal to the fallingThreshold and

alarmStartupAlarm is equal to fallingAlarm(2) or risingOrFallingAlarm(3), then a single falling alarm will be generated.

::= { alarmEntry 6 }

alarmRisingThreshold OBJECT-TYPE SYNTAX INTEGER

"A threshold for the sampled statistic. When the current sampled value is greater than or equal to this threshold, and the value at the last sampling interval was less than this threshold, a single event will be generated. A single event will also be generated if the first sample after this entry becomes valid is greater than or equal to this threshold and the associated alarmStartupAlarm is equal to risingAlarm(1) or risingOrFallingAlarm(3).

After a rising event is generated, another such event will not be generated until the sampled value

falls below this threshold and reaches the

Please refer to the current edition of the &#34;Internet Official Protocol Standards&#34

Please refer to the current edition of the "Internet Official Protocol Standards&#34