Snmp Agent Functions; Snmp Community Strings; Using Snmp To Access Mib Variables - Cisco ONS 15454 SDH Configuration Manual

SNMP Agent Functions

SNMP Agent Functions
The SNMP agent responds to SNMP manager requests as follows:
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The SNMP agent also sends unsolicited trap messages to notify an NMS that a significant event has
occurred on the agent. Examples of trap conditions include, but are not limited to, when a port or module
goes up or down, when spanning-tree topology changes occur, and when authentication failures occur.

SNMP Community Strings

SNMP community strings authenticate access to MIB objects and function as embedded passwords. In
order for the NMS to access the ML-Series card, the community string definitions on the NMS must
match at least one of the three community string definitions on the ML-Series card.
A community string can have one of these attributes:
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Using SNMP to Access MIB Variables

An example of an NMS is the CiscoWorks network management software. CiscoWorks software uses
the ML-Series card 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 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 22-2
SNMP Manager
Cisco ONS 15454 and Cisco ONS 15454 SDH Ethernet Card Software Feature and Configuration Guide, R8.0
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Get a MIB variable—The SNMP agent begins this function in response to a request from the NMS.
The agent retrieves the value of the requested MIB variable and responds to the NMS with that value.
Set a MIB variable—The SNMP agent begins this function in response to a message from the NMS.
The SNMP agent changes the value of the MIB variable to the value requested by the NMS.
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 22-2, the SNMP agent gathers data from the MIB. The agent can send traps, or
SNMP Network
NMS
get, get-next, get-bulk
get-response, traps
Network device
MIB
SNMP Agent
Chapter 22 Configuring SNMP