APC 78-10169-02 manual Operation Description, Snmp Network

Chapter 2 Monitoring the System

SNMP Basics

On the Cisco ICS 7750, the ICS System Manager software (the NMS) typically sends SNMP requests to a single IP address to access the SNMP MIBs of any system component. The SNMP agent can then respond to MIB-related queries being sent by the NMS. Similarly, if CiscoWorks2000 is the NMS, it uses the MIB variables to set device variables and poll devices on the network. You can then display the data that CiscoWorks2000 collects as a graph and analyze it to enhance network performance, to monitor traffic loads, or to troubleshoot problems. (See “Monitoring with CiscoWorks2000” on page 2-17 .)

As Figure 2-2shows, the SNMP agent gathers data from the MIB, which is the repository for information about device parameters and network data. The agent can send traps (see “Understanding Traps” on page 2-14) to the manager.

Figure 2-2 SNMP Network

	NMS	Get-request, Get-next-request,	Network device
		Get-bulk, Set-request
			MIB
		Get-response, traps
SNMP Manager			SNMP Agent

S1203a

The SNMP manager uses information in the MIB to perform the operations described in Table 2-6.

Table 2-6 SNMP Manager Operations

	Operation		Description
	get-request		Retrieves a value from a specific variable.
	get-next-request		Retrieves a value from a variable within a table.
	get-response		The reply to a get-request, get-next-request, and
			set-request sent by an NMS.
	get-bulk		(SNMP version 2 only.) Retrieve large blocks of data,
			such as multiple rows in a table, which would otherwise
			require the transmission of many small blocks of data.
	set-request		Stores a value in a specific variable.
	trap		An unsolicited message sent by an SNMP manager
			indicating that some event has occurred.
		Cisco ICS 7750 Administration and Troubleshooting Guide
78-10169-02 Rev. B0				2-13