72-3
Catalyst 4500 Series Switch, Cisco IOS Software Configuration Guide - Cisco IOS XE 3.9.xE and IOS 15.2(5)Ex
 
Chapter 72      Configuring SNMP
About SNMP
The following table identifies the characteristics of the different combinations of security models and 
levels.
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, and SNMPv2C, and SNMPv3 protocols.
SNMP Manager Functions
The SNMP manager uses information in the MIB to perform the operations described in Table 72-1.
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
(requires the 
cryptographic software 
image)
MD5 or SHA DES Provides authentication based on the HMAC-MD5 
or HMAC-SHA algorithms.
Provides DES 56-bit encryption in addition to 
authentication based on the CBC-DES (DES-56) 
standard.
Table 72-1 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
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.
get-bulk-request
2
2. The get-bulk command only works with SNMPv2 or later.
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.