Thanks to NetOptics, I've deployed their 10/100BaseT tap as a replacement for my Finisar model. The NetOptics device is intriguing in that it ships with redundant power inputs. I use a FreeBSD-based solution documented here to combine the two tap TX outputs into a single virtual interface. Beyond the Ethernet-based products shown here, NetOptics offers a variety of alternatives, including devices for tapping multiple ports.
Shortly I hope to try NetOptics new 10/100BaseT Port Aggregator Tap. This device has a single output, which removes the need for combining two TX outputs. Unlike a competitor's product, the Aggregator Tap specifically addresses the issues of combining streams which may exceed 100 Mbps:
"For cases where the NIC’s capacity is exceeded – for instance, if there is a traffic burst, and the 100 Mbps NIC is now receiving 140 Mbps of traffic – port buffering is offered as an additional innovative feature to help prevent data overload. Buffered memory handles an overflow of up to one megabyte per side of the full-duplex connection. This memory clears automatically once the NIC’s utilization is again below 100 percent."
NetOptics also plans to move the product to a PCI-based platform:
"Offered first in 10/100 models, Port Aggregator Taps will be available in a variety of configurations, including a standard rack-mount model, or a PCI-based unit designed for direct insertion into monitoring hardware. Port Aggregator Taps may also be ordered with active response capability, enabling injection of responses such as TCP resets back into the original network link."