What is the best way to monitor a network and attached devices?

Jgraves Asks:

I work at a large campus with many servers and switches from different vendors.  We have 2 internet connections, T1 and microwave.  Our main campus has many buildings joined by fiber and each of these has one or more switch and/or server in it as well.  We also have 2 branch locations which are connected over the internet with a vpn connection and we may have another going online in the next month utilizing a point-to-point connection.

What I want is a solution that aggregates the condition of all of our systems and displays the status in a meaningful way.  And it should be able to email/text the technicians when there is a problem.

Rob’s Answer:

SNMP (Simple Network Management Protocol) provides devices with a way to report their statistics to us.

"SNMP is used in network management systems to monitor network-attached devices for conditions that warrant administrative attention. It consists of a set of standards for network management, including an application layer protocol, a database schema, and a set of data objects."
http://en.wikipedia.org/wiki/Snmp

All of the devices that you describe could be monitored with SNMP enabled and software from this list:
http://www.monitortools.com/snmp/

OpManage is particularly good:
http://manageengine.adventnet.com/products/opmanager/index.html?snmpmtr

Jgrave’s Feedback:

Thanks for the info on SNMP as the backbone technology. OpManager looks like it might be our best solution.