Avaya Media Gateway G250, Руководство администратора

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Issue 5 June 2008 355
Chapter 13: Configuring SNMP
SNMP uses software entities called managers and agents to manage network devices. The
manager monitors and controls all other SNMP-managed devices or network nodes on the
network. There must be at least one SNMP Manager in a managed network. The manager is
installed on a workstation located on the network.
An agent resides in a managed device or network node. The agent receives instructions from
the SNMP Manager, generates reports in response to requests from the SNMP Manager, and
sends management information back to the SNMP Manager as events occur. The agent can
reside on:
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Routers
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Bridges
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Hubs
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Workstations
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Printers
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Other network devices
There are many SNMP management applications, but all these applications perform the same
basic task. They allow SNMP managers to communicate with agents to configure, get statistics
and information, and receive alerts from network devices. You can use any SNMP-compatible
network management system to monitor and control a G250/G350.
Agent and manager communication
There are several ways that the SNMP manager and the agent communicate. The manager
can:
●
Retrieve a value ( get ) . The SNMP manager requests information from the agent, such as
the number of users logged on to the agent device or the status of a critical process on that
device. The agent gets the value of the requested Management Information Base (MIB)
variable and sends the value back to the manager.
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Retrieve the value immediately after the variable you name ( get-next ) . The SNMP
manager retrieves different instances of MIB variables. The SNMP manager takes the
variable you name and then uses a sequential search to find the desired variable.
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Retrieve a number of values ( get-bulk ) . The SNMP manager retrieves the specified
number of instances of the requested MIB variable. This minimizes the number of protocol
exchanges required to retrieve a large amount of data.