Cisco Nexus 5000 Series Switch CLI Software Configuration Guide (OL-16597-01, July 2009)

User-Based Security Model
The following table identifies what the combinations of security models and levels mean.
Table 51: SNMP Security Models and Levels
What HappensEncryptionAuthenticationLevelModel
Uses a community
string match for
authentication.
NoCommunity stringnoAuthNoPrivv1
Uses a community
string match for
authentication.
NoCommunity stringnoAuthNoPrivv2c
Uses a username
match for
authentication.
NoUsernamenoAuthNoPrivv3
Provides
authentication based
NoHMAC-MD5 or
HMAC-SHA
authNoPrivv3
on the Hash-Based
Message
Authentication Code
(HMAC) Message
Digest 5 (MD5)
algorithm or the
HMAC Secure Hash
Algorithm (SHA).
Provides
authentication based
DESHMAC-MD5 or
HMAC-SHA
authPrivv3
on the HMAC-MD5
or HMAC-SHA
algorithms. Provides
Data Encryption
Standard (DES)
56-bit encryption in
addition to
authentication based
on the Cipher Block
Chaining (CBC)
DES (DES-56)
standard.
SNMPv3 User-Based Security Model (USM) refers to SNMP message-level security and offers the following
services:
• Message integrity—Ensures that messages have not been altered or destroyed in an unauthorized manner
and that data sequences have not been altered to an extent greater than can occur non-maliciously.
Cisco Nexus 5000 Series Switch CLI Software Configuration Guide
OL-16597-01 377
Information About SNMP
User-Based Security Model