Disclosures at the end, as usual.

This fall John Obeto asked if I’d be willing to try out some third party optical modules in some of the varied and random switches I have around the rsts11 home lab. Always willing to help a friend and try some new gadgets, I accepted the challenge. Today I’ll give you an idea of why you might consider third party optics for your switching, why you might not, and how the compatible modules from StarTech.com impressed me.

WHAT ARE OPTICAL MODULES?

First, a word on optical modules. For decades, switch manufacturers have made two kinds of ports on their switches, a fixed port and a modular port. Fixed ports were long popular on line cards, where you wanted to get 24-48 (or more) optical ports for fiber cabling into a small amount of space, and you knew your customer was not going to change their optical requirements on the fly.

Modular (or “pluggable”) ports, however, made it possible to sell switches at a lower initial cost and allow the uplinks to be populated later. It also enabled customers to use different connection lengths and media with the commensurate power considerations.

In Gigabit Ethernet (and 1/2/4 gigabit Fibre Channel), the standard has been the Small Formfactor Pluggable, or SFP, module. About the size of a AA battery or a small USB flash drive, it connects to a small blade port inside the switch, and “translates” the connection to short (SR), long, (LR), or extended/extreme (XR) range optics, or even to 1000Base-T copper.

For 10 Gigabit Ethernet (and 8/16 gigabit Fibre Channel), the standard is an extension of the same module called SFP+. Many installations within a rack or in adjacent racks will use copper SFP+ cabling (with no fiber involved), sometimes called Direct Attach Copper or DAC cabling. Continue reading →