Chapter 37 System
ZyWALL ATP Series User’s Guide
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Figure 500
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 Zyxel Device). 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.
• Set - Allows the manager to set values for object variables within an agent.
• Trap - Used by the agent to inform the manager of some events.
37.11.1 SNMPv3 and Security
SNMPv3 enhances security for SNMP management using authentication and encryption. SNMP
managers can be required to authenticate with agents before conducting SNMP management
sessions.
