Manager/Agent Model Components

SNMP provides a message format for communication between managers and agents, which use a MIB and a relatively small set of commands to exchange information. The SNMP manager can be part of a network management system, such as Extreme Networks NetSight, while the agent and MIB reside on the switch.

The SNMP agent acts upon requests from the manager to either collect data from the MIB or to set data into the MIB. A repository for information about device parameters and network data, the MIB is organized in a tree structure in which individual variables are represented as leaves on the branches. A unique object identifier (OID) distinguishes each variable in the MIB and is the means by which the manager and agent specify which managed elements are changed.

An agent can send unsolicited notification messages (also known as traps or informs) alerting the SNMP manager to a condition on the network. These conditions include such things as improper user authentication, restarts, link status (up or down), MAC address tracking, closing of a TCP connection, loss of connection to a neighbor, or other significant events.