RMON (Remote Monitoring) MIB

# History Control

Port. Any Ethernet interface on this device.

BucketsRequested. 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.

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

IntervalStart. 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.

Owner. The NMS that created this entry.

Status. 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).

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# Ether Stats Control

Port. Any Ethernet interface on this device.

Status. Valid if the agent is collecting this history.

Owner. The NMS that created this entry.

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# Alarm

Interval. 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.

Variable. 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.

SampleType. 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.

Value. 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. 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.

StartupAlarm. 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.

RisingThreshold. 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 alarmFallingThreshold.

RisingEventIndex. The index of the eventEntry that is used when a rising threshold is crossed. The eventEntry identified by a particular value of this index is the same as identified by the same value of the eventIndex object. If there is no corresponding entry in the eventTable, then no association exists. In particular, if this value is zero, no associated event will be generated, as zero is not a valid event index.

FallingThreshold. A threshold for the sampled statistic. When the current sampled value is less than or equal to this threshold, and the value at the last sampling interval was greater 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 less than or equal to this threshold and the associated alarmStartupAlarm is equal to fallingAlarm(2) or risingOrFallingAlarm(3). After a falling event is generated, another such event will not be generated until the sampled value rises above this threshold and reaches the alarmRisingThreshold.

FallingEventIndex. The index of the eventEntry that is used when a falling threshold is crossed. The eventEntry identified by a particular value of this index is the same as identified by the same value of the eventIndex object. If there is no corresponding entry in the eventTable, then no association exists. In particular, if this value is zero, no associated event will be generated, as zero is not a valid event index.

Owner. The NMS that created this entry.

Status. The status of this alarm entry.

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# Insert Alarm

Variable. The variable to monitor. Use the pulldown menu to choose a variable or type it directly into the field. Either MIB descriptors and instances or OIDs can be used. The variable must exist before it can be used. See Variable.

Sample Type. Choose delta for counters, absolute for everything else. See SampleType.

Sample Interval. The interval in seconds to monitor variable. See Interval.

Index. This entry's proposed index into the alarm table. This is computed automatically, but you can override it.

Threshold Type. Whether to check for rising and/or falling thresholds.

Value. The value that must be crossed before an event is triggered.

Event Index. The associated event. By default, DM will use 60534 for rising events and 60535 for falling events. (You can override these values.) These events log and send traps.

Severity. How serious the event is on a scale from one (high) to five (low). This is a purely arbitrary value that is simply passed on to the script.

Script. What script will be executed when the SNMP trap is received. The script will be passed in the severity level.

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# Event

Description. A comment describing this event entry.

Type. The type of notification that the probe will make about this event. In the case of log, an entry is made in the log table for each event. In the case of SNMP trap, an SNMP trap is sent to one or more management stations.

Community. If an SNMP trap is to be sent, it will be sent to the SNMP community specified by this octet string. In the future this table will be extended to include the party security mechanism. This object shall be set to a string of length zero if it is intended that mechanism be used to specify the destination of the trap.

LastTimeSent. The value of SysUpTime at the time this event entry last generated an event. If this entry has not generated any events, this value will be zero.

Owner. The NMS that created this entry.

Status. The status of this event entry. If this object is not equal to valid(1), all associated log entries shall be deleted by the agent.

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# Log

Time. The value of SysUpTime when this log entry was created.

Description. An implementation-dependent description of the event that activated this log entry.

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# Traffic

Octets. The total number of octets of data (including those in bad packets) received on the network (excluding framing bits but including FCS octets).

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

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

MulticastPkts. 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.

The total number of packets (including bad packets) received that were the following octets in length (excluding framing bits but including FCS octets):

- </= 64.
- > 65.
- > 127.
- > 255.
- > 511.
- > 1023.

[More...]

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# History

- Index. 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.
- Utilization. The best estimate of the mean physical layer network utilization on this interface during this interval, in percent.
- SampleIndex. 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.
- IntervalStart. 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.

- Octets.
- Pkts.
- BroadcastPkts.
- MulticastPkts
- DropEvents
- CRCAlignErrors
- UndersizePkts
- OversizePkts
- Fragments
- Jabbers
- Collisions

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#

Errors

DropEvents. 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.

CRCAlignErrors. 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).

UndersizePkts. 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.

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

Fragments. 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.

Jabbers. 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). We define jabber as the condition where any packet exceeds 20 ms. The allowed range to detect jabber is between 20 ms and 150 ms.

Collisions. 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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