Chapter 5. Monitoring Network Availability

Network monitoring is the concept of observing, measuring, and comparing the performance of a computer network using both technology and personnel. The purpose of network monitoring is to detect faults within a network and ensure steady network operations. Monitoring network devices is a proactive approach to troubleshooting potential performance issues. Typically, a network-monitoring system is comprised of Windows- or UNIX-based network-ready computers loaded with network-monitoring software. The network-monitoring system polls the monitored nodes at regular intervals to determine the overall health of the network and its components. Based on the polled results, the network-monitoring system generates alerts. These alerts can be e-mailed, sent through pager messages, or relayed through a web page. The network-monitoring system also stores the historical data for reporting and trending. A properly functioning network-monitoring system helps the Netadmin to do the following:

• Get a bird's-eye view of the entire network

• Determine the availability of network resources to the users

• Create trending reports for availability and outages

• Identify and respond to network issues in real time

This chapter prepares the Netadmin to understand the terminology and techniques used for network monitoring. Further discussion focuses on deploying Linux- and Windows-based network-monitoring systems using tools that are freely available in the public Internet domain.