Network Monitoring is becoming common business practice across all network.

Network and security professionals monitor their networks for a variety of reasons:

• To improve network security.
• To improve network uptime, and thus provide access to business applications.
• For capacity planning and improving end user SLAs.
• There are a variety of monitoring systems that customers use, such as: Intrusion Detection Systems: to detect unauthorized intrusions and attacks (both external and internal) on the company’s critical assets.
• Forensics systems: to identify the source of the intrusion, and possibly initiate legal
  action.
• Content inspection: to enforce corporate policy and prevent employees from accessing unauthorized web sites, such as pornographic web sites and gambling sites during work hours.
• Network analyzers for network troubleshooting.
• Rmon probes and other home grown systems, for collecting data for capacity planning and improving end user SLAs.
• Network monitoring provides significant benefits to organizations, however it comes with
  a high cost and a few deployment challenges.