Technical Library

Internet Services

SNMP Support

SNMP (Simple Network Management Protocol) is the most widely used protocol for managing TCP/IP Internets.

A network management station (NMS) uses SNMP query (poll) SNMP processes (agents) on network devices such as routers and end stations.

These agents maintain a list of variables and their values that describe the state of the network device. The variables can describe routing table entries, interface addresses, and byte counts transmitted on various interfaces. The collection of variables is described by a Management Information Base (MIB).

The MIB is divided into two sections, a public MIB which all network devices are required to implement, and private or enterprise MIBs which allow vendors to implement specific features in their SNMP agents.

The NMS must have access to the device's MIB in order to properly manage the device.

Access to the managed device is obtained by presenting the community name in each packet.

There are three types of SNMP operations:

• A QUERY is an NMS's request for the value of a MIB variable on a network device.
  
  
• A SET is an NMS's request to alter the value of a variable on a network device and change the configuration.
  
  
• A TRAP is an announcement of a significant event that the agent of the managed device sends to the NMS.