What is an example of a network management services?
Network Management Systems comprise a suite of software and network tools to monitor the status of devices on the network, and optionally manage those devices or fix issues that have come up.
The main IP "protocol" (tool) that is used for network management is referred to as SNMP or Simple Network Management Protocol. Network devices--including servers, printers, computers, routers, hubs/switches, and a host of other devices--all have SNMP either built-in for enabling and configuring, or can be equipped with SNMP through some sort of installation process.
Tivoli NetView from IBM is an example of a long-standing network management platform.
Note that network management software is necessary only for medium to very large businesses with many hundreds or thousands of devices and is therefore traditionally very expensive.