Many devices support SNMP, including routers, switches, servers, workstations, printers and Uninterruptible Power Supplies (UPS). What this means is you can use SNMP to monitor the health of your routers, servers and other pieces of network devices; which is fairly simple.

But, what exactly is SNMP?
How can I as a System or Network Administrator benefit from SNMP?
Do any of my devices support SNMP?
If so, how can I tell they are configured properly?
When does MRTG come into play, and what is it anyway?
You want to see trends at a glance; graph memory usage, load average, CPU performance and more. How can you use MRTG to make this possible?
Sometimes a picture is worth a thousand words.