User`s guide

Configuring SNMP
Page 131
Section 11. Configuring SNMP
Simple Network Management Protocol (SNMP) provides a method for managing network
devices. Equipment commonly managed with SNMP includes switches, routers and host
computers. SNMP is typically used to configure these devices for proper operation in a
network environment, as well as to monitor them to evaluate performance or detect potential
problems.
Managed devices supporting SNMP contain software, which runs locally on the device and is
referred to as an agent. A defined set of variables, known as managed objects, is maintained
by the SNMP agent and used to manage the device. These objects are defined in a
Management Information Base (MIB) that provides a standard presentation of the information
controlled by the agent. SNMP defines both the format of the MIB specifications and the
protocol used to access this information over the network.
The switch includes an onboard agent that supports SNMP versions 1, 2c, and 3. This agent
continuously monitors the status of the switch hardware, as well as the traffic passing through
its ports. Access to the onboard agent using SNMP v1 and v2c is controlled by community
strings. To communicate with the switch, the management station must first submit a valid
community string for authentication.
Access to the switch using SNMPv3 provides additional security features that cover message
integrity, authentication, and encryption; as well as controlling user access to specific areas
of the MIB tree.
The SNMPv3 security structure consists of security models, with each model having its own
security levels. There are three security models defined, SNMPv1, SNMPv2c, and SNMPv3.
Users are assigned to “groups” that are defined by a security model and specified security
levels. Each group also has a defined security access to set of MIB objects for reading and
writing, which are known as “views.”
The device has a default view (all MIB objects) and default groups defined for security
models v1 and v2c. The following table shows the security models and levels available and
the system default settings.
The SNMP agents maintain a list of variables, which are used to manage the device. The
variables are defined in the Management Information Base (MIB). The SNMP agent defines
the MIB specification format, as well as the format used to access the information over the
network. Access rights to the SNMP agents are controlled by access strings.
The device is SNMP-compliant and contains an SNMP agent that supports a set of standard
and private MIB variables. Developers of management stations require the exact structure of
the MIB tree and receive the complete private MIBs information before being able to manage