ZyXEL Communications IES-1248-51, User Manual

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IES-1248-51 User’s Guide
194 Chapter 31 Access Control
Figure 100 SNMP Management Model
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 IES-1248-
51). An agent translates the local management information from the managed device into a
form compatible with SNMP. The manager is the console through which network
administrators perform network management functions. It executes applications that control
and monitor managed devices.
The managed devices contain object variables/managed objects that define each piece of
information to be collected about a device. Examples of variables include such as number of
packets received, node port status etc. 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 52 SNMP Commands
COMMAND DESCRIPTION
Get Allows the manager to retrieve an object variable from the agent.
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.