In the world of networking, the verbiage can be very confusing. Even after getting used to having conversations about it for years, there still may be strange lingo that can throw a person off. 

Networking Basics:

The first part is data rate in megabits per second; this is the speed of the network. We work with these terms on a daily basis:

  • 10 megabits – 10BASE-X
  • 100 megabits – Fast Ethernet, 100BASE-X
  • 1000 megabits – Gigabit Ethernet, GbE, or 1000BASE-X
  • 10,000 megabits – 10 Gigabit Ethernet, 10GbE, or 10GBASE-X
  • 25,000 megabits – 25 Gigabit Ethernet, 25GbE, or 25GBASE-X
  • 40,000 megabits – 40 Gigabit Ethernet, 40GbE, or 40GBASE-X
  • 50,000 megabits – 50 Gigabit Ethernet, 50GbE, or 50GBASE-X
  • 100,000 megabits – 100 Gigabit Ethernet, 100GbE, or 100GBASE-X

So why is the next part always the word “BASE”? "BASE" is short for “baseband”, an unfiltered line not requiring a digital modulation scheme. For example, 100BASE refers to a Fast Ethernet connection that uses an unfiltered cable for transmission



The third part of an Ethernet network type refers to the cabling used to carry the signals, the earliest forms of Ethernet having used coaxial cable. In the mid-1990’s companies started using twisted-pair cabling, eventually moving forward to today where we now use fiber optics. This may seem complex but is much simpler than it appears.

The first letter tells us which kind of wire is used:

  • “T” = twisted-pair copper cable (Such as Cat5 or Cat6)
  • “K” = copper backplane
  • “C”= copper cable
  • “F” = optical cable
  • “B” = BiDi - two wavelengths over a single optical cable
  • “S” = short range multi-mode optical cable (under 550m)
  • “L” = long range single mode optical cable (10km)
  • “E” = extended range optical cable (40km)
  • “Z” = long range single mode at a higher wavelength (80km)

Next is the coding scheme for the data on the wire:

  • “X” = 4B/5B block coding for Fast Ethernet or 8B/10B block coding for Gigabit Ethernet
  • “R” = 64B/66B block coding for 10G/40G/100G

Finally, we have a number representing the number of parallel “lanes” for data:

  • “1” would mean serial (non-parallel) but is usually omitted instead
  • “4” or “10” are available for copper wire
  • Just about any number could be used for optical lanes or wavelengths (40GBASE-SR4 uses 4 lanes of 10G)

Reference - Original Article