The SNMP is an application-layer protocol that facilitates the exchange of
management information between network devices. It is part of the TCP/IP
protocol suite. SNMP enables network administrators to manage network
performance, find and solve network problems, and plan for network growth. An
SNMP managed network consists of three basic components
:
- Managed devices
- Agents
- Network-management system (NMS)
A managed device is a network node that is located on a managed network
and contains an SNMP agent. Managed devices collect and store management
information and make this information available to the NMS using SNMP. Managed
devices, which are sometimes called network elements, can be routers and access
servers, switches and bridges, APs, hubs, computer hosts, or printers. Other
key terms are shown in Figure
.
An NMS executes applications that monitor and control managed devices. An
NMS provides the bulk of the processing and memory resources required for
network management. One or more NMSs must exist on any managed network
. Managed devices
are monitored and controlled using basic SNMP commands
. An example is
shown in Figure
.
The trap
command can be configured on the AP or bridge to asynchronously report events
to the NMS. When certain types of events occur, a managed device sends a trap
to the NMS. The remaining basic commands are not yet integrated into Cisco
Aironet products.
The 1100 and 1200 IOS software release supports SNMP
versions 1 and 2 as shown in Figure
. Both SNMPv1 and
SNMPv2C use a community-based form of security. The community of managers able
to access the agent's MIB is defined by an IP address access control list
and password. The SNMP agent on the AP must be configured to use the version of
SNMP supported by the management station. An agent can communicate with
multiple managers; therefore, the software can be configured to support
communications with one management station using the SNMPv1 protocol and
another using the SNMPv2 protocol.