RFC1757 - Remote Network Monitoring Management Information Base

Network Working Group S. Waldbusser
Request for Comments: 1757 Carnegie Mellon University
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
9. Author"s Address ...................................... 90
10. Appendix: Changes from RFC1271 ...................... 91
1. The Network Management Framework
The Internet-standard Network Management Framework consists of three
components. They are:
STD 16, RFC1155 [1] which defines the SMI, the mechanisms used
for describing and naming objects for the purpose of management.
STD 16, RFC1212 [2] defines a more concise description mechanism,
which is wholly consistent with the SMI.
STD 17, RFC1213 [3] which defines MIB-II, the core set of managed
objects for the Internet suite of protocols.
STD 15, RFC1157 [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 RFC1212"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, RFC1155 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.
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
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.
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.
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.
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.
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.
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
discretion.
3.2. Row Addition Among Multiple Management Stations
The addition of new rows is achieved using the method described in
RFC1212 [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.
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
-- 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
-- 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
-- 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 }
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
STATUS mandatory
DESCRIPTION
"The value of this object uniquely identifies this
etherStats entry."
::= { etherStatsEntry 1 }
etherStatsDataSource OBJECT-TYPE
SYNTAX OBJECT IDENTIFIER
ACCESS read-write
STATUS mandatory
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 RFC1213 and RFC1573 [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
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).
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
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets (including bad packets,
broadcast packets, and multicast packets) received."
::= { etherStatsEntry 5 }
etherStatsBroadcastPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of good packets received that were
directed to the broadcast address. Note that this
does not include multicast packets."
::= { etherStatsEntry 6 }
etherStatsMulticastPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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."
::= { etherStatsEntry 7 }
etherStatsCRCAlignErrors OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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)."
::= { etherStatsEntry 8 }
etherStatsUndersizePkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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
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
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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.
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
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets (including bad
packets) received that were 64 octets in length
(excluding framing bits but including FCS octets)."
::= { etherStatsEntry 14 }
etherStatsPkts65to127Octets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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)."
::= { etherStatsEntry 15 }
etherStatsPkts128to255Octets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets (including bad
packets) received that were between
128 and 255 octets in length inclusive
(excluding framing bits but including FCS octets)."
::= { etherStatsEntry 16 }
etherStatsPkts256to511Octets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets (including bad
packets) received that were between
256 and 511 octets in length inclusive
(excluding framing bits but including FCS octets)."
::= { etherStatsEntry 17 }
etherStatsPkts512to1023Octets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets (including bad
packets) received that were between
512 and 1023 octets in length inclusive
(excluding framing bits but including FCS octets)."
::= { etherStatsEntry 18 }
etherStatsPkts1024to1518Octets OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The total number of packets (including bad
packets) received that were between
1024 and 1518 octets in length inclusive
(excluding framing bits but including FCS octets)."
::= { 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
DESCRIPTION
"The status of this etherStats entry."
::= { etherStatsEntry 21 }
-- 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
STATUS mandatory
DESCRIPTION
"A list of history control entries."
::= { history 1 }
historyControlEntry OBJECT-TYPE
SYNTAX HistoryControlEntry
ACCESS not-accessible
STATUS mandatory
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
STATUS mandatory
DESCRIPTION
"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 RFC1213 and RFC1573 [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
historyControlStatus object is equal to valid(1)."
::= { historyControlEntry 2 }
historyControlBucketsRequested OBJECT-TYPE
SYNTAX INTEGER (1..65535)
ACCESS read-write
STATUS mandatory
DESCRIPTION
"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 }
::= { historyControlEntry 3 }
historyControlBucketsGranted OBJECT-TYPE
SYNTAX INTEGER (1..65535)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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
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)
ACCESS read-write
STATUS mandatory
DESCRIPTION
"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
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
ACCESS read-write
STATUS mandatory
DESCRIPTION
"The entity that configured this entry and is
therefore using the resources assigned to it."
::= { historyControlEntry 6 }
historyControlStatus OBJECT-TYPE
SYNTAX EntryStatus
ACCESS read-write
STATUS mandatory
DESCRIPTION
"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)."
::= { historyControlEntry 7 }
-- 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.
--
etherHistoryTable OBJECT-TYPE
SYNTAX SEQUENCE OF EtherHistoryEntry
ACCESS not-accessible
STATUS mandatory
DESCRIPTION
"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
STATUS mandatory
DESCRIPTION
"The history of which this entry is a part. The
history identified by a particular value of this
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
STATUS mandatory
DESCRIPTION
"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
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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
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
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of packets (including bad packets)
received during this sampling interval."
::= { etherHistoryEntry 6 }
etherHistoryBroadcastPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of good packets received during this
sampling interval that were directed to the
broadcast address."
::= { etherHistoryEntry 7 }
etherHistoryMulticastPkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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."
::= { etherHistoryEntry 8 }
etherHistoryCRCAlignErrors OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The number of packets received during this sampling
interval that had a length (excluding framing bits
but including FCS octets) between 64 and 1518
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)."
::= { etherHistoryEntry 9 }
etherHistoryUndersizePkts OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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
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) but were otherwise well formed."
::= { etherHistoryEntry 11 }
etherHistoryFragments OBJECT-TYPE
SYNTAX Counter
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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
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
ACCESS read-only
STATUS mandatory
DESCRIPTION
"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
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)
ACCESS read-only
STATUS mandatory
DESCRIPTION
"The best estimate of the mean physical layer
network utilization on this interface during this
sampling interval, in hundredths of a percent."
::= { etherHistoryEntry 15 }
-- 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
-- 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
STATUS mandatory
DESCRIPTION
"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
STATUS mandatory
DESCRIPTION
"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
ACCESS read-write
STATUS mandatory
DESCRIPTION
"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