Remote network monitoring devices, often called monitors or probes, are instruments that exist for the purpose of managing a network. These remote probes may be embedded in routers or switches, or may be (and often are) stand-alone devices. In either case, they devote significant internal resources for the sole purpose of measuring a network. An organization may employ many of these devices, one per network segment, to manage its internet. In addition, these devices may be used for a network management service provider to access a client network, often geographically remote. These devices use the RMON MIB to communicate with a management application, which configures them to run tests and then reads out the results.

The RMON MIB allows a probe to be configured to perform diagnostics and to collect statistics continuously, even when communication with the management station may not be possible or efficient. The probe may then attempt to notify the management station when an exceptional condition occurs. Thus, even in circumstances where communication between management station and probe is not continuous, fault, performance, and configuration information may be continuously accumulated and communicated to the management station conveniently and efficiently.

Given the resources available on the monitor, it is potentially helpful for it continuously to run diagnostics and to log network performance. The monitor is always available at the onset of any failure. It can notify the management station of the failure and can store historical statistical information about the failure. This historical information can be played back by the management station in an attempt to perform further diagnosis into the cause of the problem.

The monitor can be configured to recognize conditions, most notably error conditions, and continuously to check for them. When one of these conditions occurs, the event may be logged, and management stations may be notified in a number of ways.

Because a remote monitoring device represents a network resource dedicated exclusively to network management functions, and because it is located directly on the monitored portion of the network, the remote network monitoring device has the opportunity collect data that is not immediately useful but can be reduced offline for added insight.

Note RMON-I works for Ethernet, no support for FDDI, token thing, or ATM cloud; RMON-II was intended to allow routers or switches to describe events at layers two or three on any interface, in fact the MIB claims to be able to measure up to the application layer.