SNMP Basics

SNMP is a protocol used to exchange data about network activity. With SNMP, data travels between a managed device and a network management station (NMS). A managed device is anything that runs SNMP: hosts, routers, your proxy server, and other servers on your network. The NMS is a system used to remotely manage that network. Usually, the NMS software will provide a graph to display collected data or use that data to make sure the server is operating within a particular tolerance.

The NMS is usually a powerful workstation with one or more network management applications installed. A network management application such as HP OpenView graphically shows information about managed devices, such as your web servers. This information might include which servers in your enterprise are up or down, or the number and type of error messages received. When you use SNMP with a proxy server, this information is transferred between the NMS and the server through the use of two types of agents, the subagent and the master agent.

The subagent gathers information about the server and passes the information to the server’s master agent. Every server, except for the Administration Server, has a subagent.

After making any SNMP configuration changes, you must click Apply Required, then restart SNMP subagent.

The master agent communicates with the NMS. The master agent is installed with the Administration Server.

You can have multiple subagents installed on a host computer, but only one master agent. For example, if you had Proxy Server, Oracle Directory Server Enterprise Edition, and Oracle Communications Messaging Exchange Server installed on the same host, the subagents for each of the servers would communicate with the same master agent.