ZyXEL Communications ZyWALL 300 User Manual

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 Chapter 44 Service Control
ZyWALL USG 300 User’s Guide
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44.10  SNMP 
Simple Network Management Protocol is a protocol used for exchanging management 
information between network devices. Your ZyWALL supports SNMP agent functionality, 
which allows a manager station to manage and monitor the ZyWALL through the network. 
The ZyWALL supports SNMP version one (SNMPv1) and version two (SNMPv2c). The next 
figure illustrates an SNMP management operation.   
Figure 453   SNMP Management Model
An SNMP managed network consists of two main types of component: agents and a manager. 
An agent is a management software module that resides in a managed device (the ZyWALL). 
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:
• 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.