SNMP Architecture

Use SNMP to determine where and when a network failure is occurring, and to gather statistics about network performance in order to evaluate the overall health of the network and identify bottlenecks.

Because SNMP is a client/server protocol, SNMP nodes can be classified as either clients (SNMP managers) or servers (SNMP agents). SNMP managers, also called network management systems (NMSs), occupy central points in the network and actively query and collect messages from SNMP agents in the network. SNMP agents are individual processes running on network nodes that gather information for a particular node and transfer the information to SNMP managers as queries are processed. The agent also controls access to the agent’s Management Information Base (MIB), the collection of objects that can be viewed or changed by the SNMP manager. Because SNMP agents are individual SNMP processes running on a host, multiple agents can be active on a single network node at any given time.

Communication between the agent and the manager occurs in one of the following forms:

• Get, GetBulk, and GetNext requests—The manager requests information from the agent, and the agent returns the information in a Get response message.
• Set requests—The manager changes the value of a MIB object controlled by the agent, and the agent indicates status in a Set response message.
• Traps notification—The agent sends traps to notify the manager of significant events that occur on the network device.

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