Snmp Manager Functions; Snmp Agent Functions - Allen-Bradley Stratix 5100 User Manual

SNMP Manager Functions

The SNMP manager uses information in the MIB to perform the operations
described in this table.
Table 110 - SNMP Operations
Operation Description
get-request Retrieves a value from a specific variable.
get-next-request
Retrieves a value from a variable within a table.
(1)
get-bulk-request Retrieves large blocks of data that otherwise requires that the transmission of many
small blocks of data, such as multiple rows in a table.
get-response Replies to a get-request, get-next-request, and set-request sent by an NMS.
set-request Stores a value in a specific variable.
trap An unsolicited message sent by an SNMP agent to an SNMP manager when some event
has occurred.
(1) The get-bulk command works only with SNMPv2.
(2) With this operation, an SNMP manager does not need to know the exact variable name. A sequential search is performed to find the
needed variable from within a table.

SNMP Agent Functions

The SNMP agent responds to SNMP manager requests as follows:
• 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.
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.
Rockwell Automation Publication 1783-UM006A-EN-P - May 2014
Configuring SNMP Chapter 19
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