Essential SNMP, 2nd Edition

Cricket

Cricket can be loosely associated with MRTG because it is an interface to RRDtool. It facilitates the following:

• Data gathering (using SNMP, command-line tools, and so on)

• Creating RRDtool database(s)

• Updating data points in the RRDtool database

• Presenting accumulated data (over time) as graphs in a web page

Cricket allows users to view graphs over the following time periods:

• Daily

• Weekly

• Monthly

• Yearly

The main web site for Cricket is http://cricket.sourceforge.net.

Cricket's History

While working for WebTV^[*] in 1998, Jeff Allen originally conceived of Cricket. Jeff wanted to find a way to reduce the complexity of WebTV's MRTG configuration and deployment. At that time, Tobias Oetiker, author of MRTG, released RRDtool. Once Jeff saw RRDtool, he began to see how its design could aid in solving many of WebTV's MRTG woes. MRTG had been known as the tool used for graphing router data. Jeff wanted a new way to graph other things as well, like data from servers.

Cricket's Config Tree

Understanding the config tree is critical to understanding how to use and modify Cricket. Everything Cricket knows it learns from the config tree. That includes things like which variables to fetch for a certain type of device, how to fetch those variables, which devices to talk to, and the device types. The inheritance property of the config tree applies equally to all types of data, making it possible to create a concise description of a large, complicated set of monitored devices.

At the top of the config