Snmp Community Strings; Using Snmp To Access Mib Variables - Cisco 2950G 24 - Catalyst Switch Software Configuration Manual

Understanding SNMP

SNMP Community Strings

SNMP community strings authenticate access to MIB objects and function as embedded passwords. In
order for the NMS to access the switch, the community string definitions on the NMS must match at least
one of the three community string definitions on the switch.
A community string can have one of these attributes:
•
•
•
Note When a cluster is created, the command switch manages the exchange of messages among member
switches and the SNMP application. The Cluster Management software appends the member switch
number (@esN, where N is the switch number) to the first configured RW and RO community strings on
the command switch and propagates them to the member switches. For more information, see
"Clustering Switches."

Using SNMP to Access MIB Variables

An example of an NMS is the CiscoWorks network management software. CiscoWorks 2000 software
uses the switch MIB variables to set device variables and to poll devices on the network for specific
information. The results of a poll can be displayed as a graph and analyzed to troubleshoot
internetworking problems, increase network performance, verify the configuration of devices, monitor
traffic loads, and more.
As shown in
notification of certain events, to the SNMP manager, which receives and processes the traps. Traps alert
the SNMP manager to a condition on the network such as improper user authentication, restarts, link
status (up or down), MAC address tracking, and so forth. The SNMP agent also responds to MIB-related
queries sent by the SNMP manager in get-request, get-next-request, and set-request format.
Figure 24-1 SNMP Network
SNMP Manager
For information on supported MIBs and how to access them, see
Catalyst 2950 Desktop Switch Software Configuration Guide
24-4
Read-only (RO)—Gives read access to authorized management stations to all objects in the MIB
except the community strings, but does not allow write access
Read-write (RW)—Gives read and write access to authorized management stations to all objects in
the MIB, but does not allow access to the community strings
Read-write-all—Gives read and write access to authorized management stations to all objects in the
MIB, including the community strings
Figure 24-1, the SNMP agent gathers data from the MIB. The agent can send traps, or
Get-request, Get-next-request,
NMS
Get-bulk, Set-request
Get-response, traps
Chapter 24
Network device
MIB
SNMP Agent
Appendix A, "Supported MIBs."
Configuring SNMP
Chapter 6,
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