The first analyzer of its kind on the market, DominoGigabit lists for $41,000--which is more than some gigabit network equipment. Targeted for field support, DominoGigabit's relatively small size makes it easily portable. However, it's a little cumbersome without a carrying handle. And, though the enclosed manuals are reasonably easy to understand, they should provide more detail about the impact certain settings will have on your network than they do.

DominoGigabit is compatible with Wandel & Goltermann's Mentor expert analysis software (see "Wandel & Goltermann's Mentor: Guide to Network Management," at www.networkcomputing.com/914/914sp1.html).

A Healthy Dose of Hardware A combination hardware-software product, DominoGigabit is a dedicated network sniffing box with its management and analysis software loaded on a host laptop. The laptop connects to the analyzer via a parallel port connection. The parallel port is somewhat slow, but it guarantees compatibility with most of the hardware. A longer parallel cable would provide more freedom of movement during testing.

I hooked up DominoGigabit to the production network at the University of Wisconsin's Computer-Aided Engineering (CAE) Center. I connected it to a Compaq Computer Corp. 5411 Enterprise switch, a 3Com Corp. SuperStack II 3900 switch and a Lucent Technologies P550 Cajun switch. While establishing a link to these devices, DominoGigabit was a bit finicky, but once the link was set, it effortlessly sliced packets off the network.

DominoGigabit operates in two modes: emulate and monitor. I tested most of its features in emulate mode, which lets you plug the analyzer into a port on your gigabit hardware, while simulating an end station on your network. This gives you the option of connecting directly to a switching device without interrupting network traffic. And, you can manipulate or build packets that you can retransmit to the network for diagnostic purposes. With emulate mode, you must hook up DominoGigabit to a switch with port mirroring capabilities.

In contrast, with monitor mode, you need to set up the analyzer between two switching devices, usually on a backbone. Thus configured, DominoGigabit can perceive all of the network traffic being transmitted across your backbone and not interfere with network flow. This is useful for examining the traffic funneled from one backbone link to another. In this mode, the analyzer does not actively participate in the network, and the device is unable to transmit information onto the network.