Ethernet overview

Ethernet (IEEE 802.3) is the dominant technology for local and data-centre networks. Over fibre it is carried by optical transceivers, and the module you choose is tied to the Ethernet rate and reach you need.

Rates and modules

Ethernet has grown by roughly an order of magnitude at each step, and each rate maps to common transceiver form factors:

Lanes and breakout

Higher rates are often built from several lanes — for example 100GbE as 4×25G. That is why a QSFP28 can be broken out into four SFP28 links, and a 400G port into 4×100G. The form factor reflects how many lanes a module carries.

Naming

Optical Ethernet interfaces have names like 10GBASE-SR or 100GBASE-LR4. What those suffixes mean is covered in Optical Ethernet interfaces.