Cisco ONS 15327, User Documentation

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11-2
Cisco ONS 15327 User Documentation, R3.3
June 2002
Chapter 11 SNMP
SNMP Basic Components
Figure 11-1 A basic network managed by SNMP
11.2 SNMP Basic Components
An SNMP-managed network consists of three primary components: managed devices, agents, and
management systems. A managed device is a network node that contains an SNMP agent and resides on
an SNMP-managed network. Managed devices collect and store management information and use
SNMP to make this information available to management systems that use SNMP. Managed devices
include routers, access servers, switches, bridges, hubs, computer hosts, and network elements such as
an ONS 15327.
An agent is a software module that resides in a managed device. An agent has local knowledge of
management information and translates that information into a form compatible with SNMP. The SNMP
manager gathers data from the SNMP agent using a Management Information Base (MIB), which is a
textual (ASN.1) representation of management information such as device parameters and network data.
The agent can also send traps, or notification of certain events, to the manager.
Figure 11-2 illustrates
these SNMP operations.
Figure 11-2 SNMP agent gathering data from an MIB and sending traps to the manager
A management system such as HP OpenView NNM executes applications that monitor and control
managed devices. Management systems provide the bulk of the processing and memory resources
required for network management. One or more management systems must exist on any managed
network.
Figure 11-3 illustrates the relationship between the three key SNMP components.
52582
get-next-request, get-bulk
Network device
get-response, traps
32632
SNMP Manager
NMS
MIB
SNMP Agent