NetOptics iTap

Why use a tap to count stats you could get from any network-monitoring tool or probe? I asked myself that question as I set up a fiber SX iTap on our Real-World Labs® on Syracuse University's backbone. The answer is about keeping it simple. The effort required to crank up a monitoring system is overkill when all you want to know is whether a particular link has problems.

So, I'm at the rack, and instead of patching a monitor in, waiting for it to gather data and then finding a computer to view the monitoring system's user interface, I just look at the tap, see the peaks and note whether there were threshold violations or alarms.

The iTap input interfaces can be SX, LX or copper with one or two output (monitoring) ports. The unit comes with dual-redundant power supplies and a 19-inch 1U mounting bracket that holds two taps.

ITap provides a diagram right on the tap showing how it should be wired, which I found convenient when I was in the wiring room without the manual. ITap's front-panel LED displays quick traffic stats, which gave me the feedback I needed to be sure I was connecting to the right link and what that link's status was before I set up any monitoring equipment.

The iTap needs an IP address to communicate with its management console through its internal Web server, and to send SNMP traps. I usually sit at my desk and set an appliance's IP, then hulk it down to the bowels of the network to plug it in. ITap's configuration interface displayed a menu: Choose a number, set an IP value. Seemed simple, but the value didn't display when set. Rather, a clunky redisplay of the configuration option is required to see if the value has set.

But the real problem is that the iTap lacks a nonvolatile memory store to maintain a set configuration--the config is lost every time the iTap loses power. NetOptics says it plans to add nonvolatile memory.

Flexible ManagementThe iTap is built for flexible control. The front-panel display and alarm LED show current bandwidth and network peaks with time stamps. The alarm LEDs light when utilization thresholds are violated.

The unit also supports a simple Web server with a single HTML page that displays utilization and link counters, including statistics on total packets, total bytes, CRC (cyclic redundancy check), collisions, current rates and peak utilizations for both transmit and receive. Alternately, you can use the 32-bit Systems Manager, NetOptic's grouping application, to view in one place the same kinds of activities across all the NetOptics' taps you've installed.

Finally, the utilization and statistics counters collected by iTap are output into an SNMP NetOptics enterprise MIB for compilation into third-party enterprise management applications. A failure trap can currently be sent, and NetOptics says it plans to add traps for link, power and threshold violations.

Bruce Boardman, executive editor of Network Computing, tests and writes about network and systems management. Write to him at [email protected].