What's the deal with SNMP? Well, the 'deal' is that people wanted a flexible, relatively low overhead way to manage their network. They wanted a way to read and set information, and have devices inform them when something goes wrong, or is about to go wrong. The result is SNMP. Now, why "Simple", when, as we shall see, it's actually pretty complex. Well, it's "Simple" in the sense that there's not much to it. There's about three things that can happen in SNMP:
1. You can query a value and get a reply
2. You can set a value and get a return code
3. An SNMP-enabled device can send you a notification, or "trap"
That's pretty much the entire range of SNMP right there, and of the three, two is the least common. It's what you do with those numbers that gives you the power, or rather, what utilities like Nagios, Cacti, and Lithium do with the numbers that make things interesting.