About the SNMP implementation in NetCache

What the SNMP process does

If SNMP is enabled in NetCache, NetCache will respond to SNMP requests and SNMP traps whenever specific events occur, and sends these traps to the SNMP managers. (A trap monitors a specific occurrence on the NetCache appliance; for example, a trap can monitor the disks on a NetCache appliance.) The SNMP managers might then carry out actions based on information received in the trap notifications.

SNMP agent and MIB groups supported

For diagnostic and other network management services, NetCache supports an SNMP version 1 compatible agent. This agent provides support for the MIB-II specification and a Network Appliance custom MIB. The following MIB-II groups are supported:

System
Interfaces
Address translation
IP
ICMP
TCP
UDP
SNMP
Note
Transmission and EGP MIB-II groups are not supported.

The Network Appliance custom MIB is discussed in Groups and objects in the custom MIB.

About traps

You set traps to inspect the value of MIB variables periodically. Whenever the value of a MIB variable meets the conditions you specify, a trap is sent to the network management stations on the trap host list in the NetCache SNMP configuration. The trap host list identifies the network management stations that receive the trap information.

You can set traps on any numeric variable in the MIB. For example, you can set a trap to monitor the disks on a NetCache appliance and have the SNMP application on your network management station display a flashing message on your console that informs you that a disk has failed.

Types of traps in NetCache

There are two types of traps in NetCache:

Built-in--Built-in traps are predefined in NetCache and are automatically sent to the network management stations on the trap host list if an event occurs. These traps are based on
- RFC 1213, such as coldStart, linkDown, linkUp, and authenticationFailure
- Specific traps defined in the Network Appliance custom MIB, such as diskFailedShutdown, cpuTooBusy, and overTempShutdown
Because the built-in traps track environmental conditions, they can vary between NetCache models.
User-defined--User-defined traps exist only after you create them using the Appliance Manager or the command line interface.
See About user-defined traps for more information.

SNMP limits in NetCache

The NetCache appliance supports the following SNMP limits:

Specification of up to eight communities. A community is a name that is used as a password by the SNMP manager to communicate with the NetCache SNMP agent.
Trap notifications for up to eight management stations (trap hosts).

Where to get more information

See the following RFCs (Requests For Comments) for more information:

RFC 1157--Defines and describes SNMP.
RFC 1213--Defines and describes the SNMP MIB-II specification.