Chapter 21 Remote Management
21.4 The SNMP Screen
Simple Network Management Protocol (SNMP) is a protocol used for exchanging management information between network devices. Your
An SNMP managed network consists of two main components: agents and a manager.
An agent is a management software module that resides in a managed device (the
The managed devices contain object variables/managed objects that define each piece of information to be collected about a switch. Examples of variables include number of packets received, node port status and so on. A Management Information Base (MIB) is a collection of managed objects. SNMP allows a manager and agents to communicate for the purpose of accessing these objects.
SNMP itself is a simple request/response protocol based on the manager/agent model. The manager issues a request and the agent returns responses using the following protocol operations:
Table 114 SNMP Commands
COMMAND | DESCRIPTION |
Get | Allows the manager to retrieve an object variable from the agent. |
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GetNext | Allows the manager to retrieve the next object variable from a table or list |
| within an agent. In SNMPv1, when a manager wants to retrieve all |
| elements of a table from an agent, it initiates a Get operation, followed by a |
| series of GetNext operations. |
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Set | Allows the manager to set values for object variables within an agent. |
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Trap | Used by the agent to inform the manager of some events. |
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