Basically everything connected to the network we can consider as a service. If there is some device on the network it always suits its purpose which is exactly providing a service. There are only different methods of checking those services availability.

Basic Level

Some of the services (devices) can be checked by a simple PING where some others can be checked more thoroughly by Network Services monitors. We call these monitors intelligent pings because they can check not only connectivity but also response received.

NetCrunch monitors availability of over 65 predefined TCP/UDP network services, including DNS, FTP, HTTP, POP3, SMTP, etc. It can monitor network services performance measured upon number of packets sent and received, response time, and percentage of packets received and lost.

The monitored services can be customized and administrators can add their own definitions.

Advanced Level - User Experience Monitors

Monitoring of some important services can be performed on multiple levels. As the low level checks only basic service answer (it's usually some kind of HELLO), the higher levels of monitoring allow to check more specific things like authentication (HTTP, FTP, POP3, SMTP) or if the service is operating properly (i.e. downloading file, receiving and sending test email).