61200.070L1-1 Express XL/XLT User Manual 139
Appendix CSNMP

Understanding SNMP

As Local Area Network (LAN) environments became standardized over the
past ten years, multi-vendor equipment grew with competition. It became
necessary to manage the various vendor equipment from a single control con-
sole. Thus, the Simple Network Management Protocol (SNMP) emerged as
the de facto standard for managing commercial Transmission Control Proto-
col/Internet Protocol (TCP/IP) networks.
The term SNMP broadly refers to the message protocols used to exchange in-
formation between the network and the managed devices, as well as to the
structure of network management databases. SNMP has three basic compo-
nents:
•Network Manager: This is a control program that collects, controls, and
presents data pertinent to the operation of the network devices. It resides
on a network management station.
•Agent: This is a control program that responds to queries and commands
from the network manager and returns requested information or invokes
configuration changes initiated by the manager. It resides in each network
device connected.
•MIB: This is an index to the organized data within a network device. It
defines the operating parameters that can be controlled or monitored.
When requesting the network manager to retrieve or modify a particular piece
of information about a network device, the network manager transmits the re-
quest to that network device. The agent in that device interprets the incoming
request, performs the requested task, and sends its response to the network
manager. The network manager collects all the data from the various network
devices and presents it in a consistent form.