Network Performance Monitoring

Network connectivity and response time can be monitored with basic tools such as ping and traceroute or with more advanced tools such as Ping-MIB, Cisco IP SLA, external probes, or a monitoring application running at the PC or server. When measuring the network connectivity and response time, we recommended that the administrator monitor connectivity between the network devices and also to the servers. This can avoid finger-pointing between the networking and server departments.

In the context of network performance, we distinguish between the downtime measured by an application and the downtime experienced by a user. If you just monitor network and server availability and do not monitor the actual service (which runs on the physical server), we could measure 100 percent availability, even if this service has an availability of no more than 90 percent. Another example is related to the measurement interval. If the performance monitoring application pings the devices only every 5 minutes, the result could be 100 percent availability, even if there are short outages during the measurement interval. A user would experience these outages and argue that the measurement is inaccurate, even though in this case both parties are right. A similar situation could occur during the night. The user probably sleeps and does not care about the network, while the server is monitoring outages. You can already imagine the challenges of service level definitions and monitoring.