Chapter 40 System
UAG4100 User’s Guide
399
Figure 280
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 UAG). 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.
40.11.1 Supported MIBs
The UAG supports MIB II that is defined in RFC-1213 and RFC-1215. The UAG also supports private
MIBs (private.mib and enterprise.mib) to collect information about CPU and memory usage. The
focus of the MIBs is to let administrators collect statistical data and monitor status and
performance. You can download the UAG’s MIBs from www.zyxel.com.
