Cisco Systems 3750E Snmp Manager Functions, Model Level Authentication Encryption Result, Des

Chapter 33 Configuring SNMP

Understanding SNMP

Table 33-1identifies the characteristics of the different combinations of security models and levels.

Table 33-1	SNMP Security Models and Levels
Model	Level	Authentication	Encryption	Result
SNMPv1	noAuthNoPriv	Community string	No	Uses a community string match for authentication.
SNMPv2C	noAuthNoPriv	Community string	No	Uses a community string match for authentication.
SNMPv3	noAuthNoPriv	Username	No	Uses a username match for authentication.
SNMPv3	authNoPriv	MD5 or SHA	No	Provides authentication based on the HMAC-MD5
				or HMAC-SHA algorithms.
SNMPv3	authPriv	MD5 or SHA	DES	Provides authentication based on the HMAC-MD5
	(requires the			or HMAC-SHA algorithms.
	cryptographic universal			Provides DES 56-bit encryption in addition to
	software image)			authentication based on the CBC-DES (DES-56)
				standard.

You must configure the SNMP agent to use the SNMP version supported by the management station. Because an agent can communicate with multiple managers, you can configure the software to support communications using SNMPv1, SNMPv2C, or SNMPv3.

SNMP Manager Functions

The SNMP manager uses information in the MIB to perform the operations described in Table 33-2.

Table 33-2	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-request2		Retrieves large blocks of data, such as multiple rows in a table, that would
		otherwise require the transmission of many small blocks of data.
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.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.

2.The get-bulkcommand only works with SNMPv2 or later.

Catalyst 3750-E and 3560-E Switch Software Configuration Guide

OL-9775-02 33-3