As networks grow more complex it can become an almost gargantuan task to continually document the devices, addresses,...
connections and other physical and topological features. Few networks are entirely planned and controlled; most grow organically adding a hub here, a network storage device there, and computers everywhere. Yet it is very important to understand the assets that you have and how they are deployed. Many asset management packages will tell you what you have, but they don't illustrate the relationships between devices.
Microsoft's Office tool Visio started life as a diagramming package. If you buy the standard version, that's just what you get. However, the Enterprise version adds a number of discovery and diagram tools that are particularly useful to a network manager. In particular, Visio Enterprise Edition added tools from InfoModeler in the form of a network object Database viewer, as well as an AutoDiscovery feature and an 18,000 network equipment shape library.
When you run the network AutoDiscovery process, Visio finds devices that issue SNMP packets and catalogs them. It builds a topology from the responses and can diagram that topology. The Logical Network Diagram that is built from this process is updated and can spot down connections and other programs. Each device has a properties sheet that will list information such as asset number, purchase date, vendor telephone numbers, and a graphical representation of the condition of the device. A router with a down port will show that problem. You'll find a description of Visio's network diagramming solution at Microsoft.
There are several other products on the market that do network discovery based on SNMP. Network View, WhatsUp Gold, SolarWinds and NetViz are a few examples. If you use an enterprise framework then you should investigate which packages are compatible with that framework as a snap-in product.
Barrie Sosinsky is president of consulting company Sosinsky and Associates (Medfield MA). He has written extensively on a variety of computer topics. His company specializes in custom software (database and Web related), training and technical documentation.