XFP Optics Guide

XFP optics are 10G pluggable modules in the XFP form factor, an early 10G format that predates SFP+. The format was designed when 10G was new, and it served the first generation of 10G routers, switches and transport equipment. That equipment is still in service in large numbers, and it still needs XFP modules, because its slots cannot take any other format. The XFP family is therefore a maintenance family as much as a current family: its value lies in keeping working equipment running.

The family on this site covers the familiar variant pattern. The fully specified model is the XFP LR, whose detail page states a 10G rate, a 1310nm wavelength, a 20km reach over single-mode fiber, a rate range of 9.95 to 11.1Gb/s, a duplex LC connector, power consumption below 2.5W and a 0 to 70 degree Celsius operating range, with applications in SDH, 10GBASE-LR and LW, and 10G Fibre Channel. The remaining titles — short-reach, extended-reach, extra-long-reach, bidirectional and wavelength-division variants — are listed at series level on the XFP series page, with no figures invented for them.

The rate range of the LR model deserves a note, because it illustrates something general about XFP optics. A single XFP module family can serve Ethernet, SDH and SONET transport, and Fibre Channel, because those applications run at slightly different rates within the same 10G band. A buyer should state the application during the inquiry — Ethernet, SDH or Fibre Channel — so the right configuration can be confirmed, because a module that covers several rates still needs to be set for the network it will run in.

Sourcing XFP optics today is a different problem from sourcing current formats. Production has shifted to SFP+ and faster formats, and XFP titles are produced in smaller volumes for a maintenance market. That makes availability the first question, ahead of price or specification: a title that cannot be supplied is no use at any price. Stating the title by name, the equipment it will plug into, and the link it will serve during the inquiry is the fastest route to a specific answer about availability.

The comparison with SFP+ is covered in the XFP versus SFP+ guide on this site, and the short version is that the slot decides. If the equipment has XFP slots, the answer is XFP. If it has SFP+ slots, the answer is SFP+. Before ordering, confirm quantity, price and delivery time during the inquiry. Certificates are available upon request.