# RMON History Control

Device > Configure > RMON > RMON History Control

This dialog box displays RMON history control information for this device.

To view the definition for a particular MIB variable, click the appropriate link from the following list:

- Index (historyControlIndex)

- Data Source (historyControlDataSource)

- Requested Buckets (historyControlBucketsRequested)

- Granted Buckets (historyControlBucketsGranted)

- Control Interval (historyControlInterval)

- Control Owner (historyControlOwner)

- Control Status (historyControlStatus)

The following list specifies buttons in this dialog box, as well as their function:

- Click OK to continue.

- Click Apply to save the changes in the dialog box.

- Click Cancel to close the dialog box.

- Click Refresh to update the contents of the dialog box.

- Click Print to print the contents of the dialog box.

- Click Help to access online help.

Index (historyControlIndex)

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

Data Source (historyControlDataSource)

Identifies the source of data for which historical data was collected and placed in a media-specific table for this historyControlEntry. The source can be any interface on this device. In order to identify a particular interface, this object identifies an instance of the ifIndex object (defined in RFC 1213 and RFC 1573 [4,6]) for the desired interface. For example, if an entry is to receive data from interface number 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. This object may not be modified if the associated historyControlStatus object is set to "valid(1)".

Requested Buckets (historyControlBucketsRequested)

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.

Granted Buckets (historyControlBucketsGranted)

Number of discrete sampling intervals over which data is to 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 is deleted by the agent to make room for the new bucket.

Control Interval (historyControlInterval)

Interval, in seconds, over which 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 3,600 (1 hour).

Because the counters in a bucket may exceed their maximum value without any indication, an administrator should 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 usually 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)".

Control Owner (historyControlOwner)

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

Control Status (historyControlStatus)

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