As with all products, you get what you pay for, but this doesn't mean free products are risky. Most free network-management tools perform tasks so simple and so straightforward--pinging, looking up names, serving files--you can be confident they'll work. For this simple stuff, support just isn't that important.
But as you rely on deeper functionality, such as packet capture, decode and network-performance assessment, you'll need to look more closely at support. MRTG (Multi Router Traffic Grapher), which is free and graphs SNMP values, has a great support community. However, everyone within that community contributes only out of his or her good graces. So if you don't have the time, you'd better have the money to invest in a fully supported corporate (read: expensive) solution.
Cheap network utilities and network-management products are easy to find and easy to use. So why would anyone consider the big, expensive network-management suites from the likes of Computer Associates, IBM and BMC Software? It depends on your organization's goals. If the network is making money or directly supports money-making transactions, you probably have to bite the bullet and invest in a centralized relational database with common data formats and maintenance contracts--it will be worth the cost.
Simple network-management utilities and tools can't handle growing networks nor survive major catastrophes in their operating environments. They have no common data store, distributed processing or redundancy. But the more strategic network-management products have become costly and difficult to implement in the attempt to solve those problems.
It's simpler to save gathered inventory data in a flat ASCII file, for instance, if all you need from the data store is a printout of devices found during a ping sweep. However, if the discovered network devices will be polled by an SNMP performance-management application and this information will be used to determine what devices need service contracts, the ability to share that data becomes valuable. It's easier to share using SQL queries than by building specific parses on data stored in a flat file; but implementing a SQL database costs more.
Another issue simple network-management tools don't address is distributed processing. Polling a device on a LAN for SNMP utilization and error information uses very little bandwidth. However, if the router, server or remote LAN is accessed over a WAN, even the small amount of bandwidth required for this retrieval may be too much. The more complex network-management products build specialized polling and compressed data-transport mechanisms to preserve the narrow WAN bandwidth.
Before you choose a direction, keep in mind that tools, whatever their cost, do not a network-management solution make. In the end, they're are only a small part of what enables good network management. The people who manage the tools matter most.
Bruce Boardman is executive editor of Network Computing. Write to him at bboardman@nwc.com.
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