# Viewing history using EDM

Ethernet history records periodic statistical samples from a network. A sample is called a history and is gathered in time intervals referred to as "buckets."

Histories establish a time-dependent method for gathering RMON statistics on a port. The default values for history are:

- Buckets are gathered at 30-minute intervals.

- Number of buckets gathered is 50.

Both the time interval and the number of buckets is configurable. After the last bucket is reached, bucket 1 is dumped and "recycled" to hold a new bucket of statistics. Then bucket 2 is dumped.

Use the following procedure to view RMON history.

## Prerequisites

- Open one of the supported browsers.

- Enter the IP address of the switch to open an EDM session.

## Procedure steps

1. From the navigation tree, double-click Serviceability.

2. In the Serviceability tree, double-click RMON.

3. In the RMON tree, double-click Control.

4. In the work area, click the History tab to view RMON history.

## Variable definitions

The following table describes the fields of the History tab.

Field | Description
--- | ---
Index | Indicates a unique value assigned to each interface. An index identifies an entry in a table.
Port | Indicates an Ethernet interface on the device.
BucketsRequested | Indicates 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 entry.
BucketsGranted | Indicates the number of discrete sampling intervals over which data is saved in the part of the media-specific table associated with this entry. There are instances after 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 is added to the media-specific table.
Interval | Indicates the interval in seconds over which the data is sampled for each bucket in the part of the media-specific table associated with this entry. You can set this interval to a number of seconds between 1 and 3600 (1 hour). Because the counters in a bucket may overflow at their maximum value with no indication, note the possibility of overflow in the associated counters. Consider the minimum time in which a counter could overflow on a particular media type and set the historyControlInterval object to a value less than this interval. This interval is typically most important for the octets counter in a 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 | Indicates the network management system that created this entry.