Chapter 29 System
NXC Series User’s Guide
368
An agent is a management software module that resides in a managed device (the NXC). 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.
29.11.1 Supported MIBs
The NXC supports MIB II that is defined in RFC-1213 and RFC-1215. The NXC also supports private MIBs
(zywall.mib and zyxel-zywall-ZLD-Common.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 NXC’s MIBs from www.zyxel.com.
29.11.2 SNMP Traps
The NXC will send traps to the SNMP manager when any one of the following events occurs.
Table 178 SNMP Traps
OBJECT LABEL OBJECT ID DESCRIPTION
Cold Start 1.3.6.1.6.3.1.1.5.1 This trap is sent when an agent reinitialized or its configuration
tables have been changed.
linkDown 1.3.6.1.6.3.1.1.5.3 This trap is sent when the Ethernet link is down.
linkUp 1.3.6.1.6.3.1.1.5.4 This trap is sent when the Ethernet link is up.
authenticationFailure 1.3.6.1.6.3.1.1.5.5 This trap is sent when an SNMP request comes from non-
authenticated hosts.
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