Workshop

Figure 22.1 The MG-Soft MIB browser is a good way to start getting familiar with SNMP and MIBs.
Whoa! What’s an MIB? MIB stands for managed information base and is a shorthand way of referring to
all the resource variables that exist in one group. For instance, just about all SNMP agents will respond to
MIB-I and MIB-II variables, such as SysContact, SysName, SysLocation for record keeping,
and ifOutOctets and ifInOctets, referring to the number of bytes received or transmitted by an
interface (if). Of course, you need a network management station to be able to read variables from an
agent.
Many manufacturers provide their own MIBs, because they have specific information that isn’t contained
in the general MIBs. For example, my GroupWise system has a couple of specific variables in its MIBs
that wouldn’t be useful for any other system (for example, poaUndeliverableMsgs, which stands
for Post Office Agent’s Undeliverable Messages). Presumably, the agent that lives on the device or
software already knows about its MIB; however, an MIB file exists that allows you to “export” the MIB
to a network manager that doesn’t know about it.
The MIB browser from Figure 22.1 provides a good way for you to tool around the MIB and SNMP
world. It includes an MIB compiler so that you can insert vendor-supplied MIBs and check out the
information that the agent supplies. Cool!
Okay, so having an SNMP agent on a device allows you to keep track of millions of resources at once.
This is neat, but what about alerts? That is, when something goes out of its threshold, how does SNMP
tell you about it?
Previous Table of Contents Next