The Ethernet Standards

“Man is something that shall be overcome. What have you done to overcome him?” (Thus Spoke Zarathustra, Nietzsche)

Overview of Ethernet Standards

IEEE, short for Institute for Electrical and Electronics Engineers, is an institute that develops standards in many industries, and the Ethernet standards are developed by IEEE-SA, IEEE Standards Association. Today, IEEE 802.3 serves as the standard that defines Ethernet protocols, providing the foundation for modern wired network communications.

The goal of this standardization is to ensure equipments are compatible (inter-operation), so as to expand marketplace and benefit both manufacturers and consumers. Therefore, devices not specified within the IEEE 802.3 standard are typically vendor-specific.

IEEE Supplements

A letter designation is used to address different types of media and technologies used in Ethernet networks. For example:

SupplementDescription
802.3u-1995100BASE-T Fast Ethernet and Auto-Negotiation
802.3z-19981000BASE-X Gigabit Ethernet over fiber optic cables
802.3ab-19991000BASE-T Gigabit Ethernet over twisted-pair cables
802.3az-2010Energy-Efficient Ethernet

Note that standards developing and publishing lags behind the innovation, especially in the field of computer networking. Therefore, it’s possible, and not necessarily a drawback, for a product to be built to draft standards.

IEEE Media System Identifiers

There are three key components of identifiers:

  • Speed: indicates the data transmission rate, such as 10 Mbps, 100 Mbps, or 1 Gbps
  • Type of signaling: indicates the transmission method, such as baseband signaling or encoding schemes
  • Physical medium: indicates the type of cable, such as twisted-pair, fiber optic, or coaxial cable

The following table provides a detailed breakdown of these identifiers and their meanings:

Media SystemsDetails
10BASE5
  • 10 megabits per second (Mb/s) transmission speed
  • “BASE”: Baseband transmission, where the entire bandwidth of the physical medium is exclusively used to transmit Ethernet signals.
  • 500-meter max length
  • → Thick Ethernet, using thick coaxial cables for data transmission
    10BASE2
  • 10 Mb/s transmission speed
  • Baseband transmission
  • 185-meter max length (round to 2)
  • → Thin Ethernet (Cheapernet), using thinner coaxial cables compared to 10BASE5
    10BASE-T
  • 10 Mb/s transmission speed
  • Baseband transmission
  • A hyphen, “-”, is used to distinguish the older “length” designators from the newer “media type” designators.
  • “T”: Twisted-pair wiring (2 pairs, CAT 3 or better)
  • 100BASE-X
  • 100 Mb/s (Fast Ethernet) transmission speed
  • Baseband transmission
  • “X”: Use of a blocking encoding scheme
  • → Includes both 100BASE-TX and 100BASE-FX, based on the same 4B/5B block signal encoding system
    100BASE-TX
  • 100 Mb/s transmission speed
  • Baseband transmission
  • Twisted-pair wiring (over 2 pairs of CAT 5 cables)
  • → Mostly used variety of Fast Ethernet
    100BASE-FX
  • 100 Mb/s transmission speed
  • Baseband transmission
  • “F”: Fiber optic cable (multimode)
  • 1000BASE-SX
  • 1000 Mb/s (Gigabit Ethernet) transmission speed
  • Baseband transmission
  • “S”: Short-wavelength fiber optic media segments
  • 1000BASE-LX
  • 1000 Mb/s transmission speed
  • Baseband transmission
  • “L”: Long-wavelength fiber optic media segments
  • 1000BASE-T
  • 1000 Mb/s transmission speed
  • Baseband transmission
  • Twisted-pair wiring (over CAT 5 or better)
  • It is based on different signal encoding scheme, compared to the above Gigabit Ethernet systems.
  • 10GBASE-SR
  • 10 Gb/s Ethernet transmission speed
  • Baseband transmission
  • “SR”: Short-range multi-mode fiber optic cable
  • 10GBASE-LR
  • 10 Gb/s Ethernet transmission speed
  • Baseband transmission
  • “LR”: Long-range multi-mode fiber optic cable
  • 10GBASE-T
  • 10 Gb/s transmission speed
  • Baseband transmission
  • Twisted-pair wiring (over CAT 6A or better)
  • 40GBASE-SR4
  • 40 Gb/s transmission speed
  • Baseband transmission
  • Over 4 short-range multi-mode fiber optic cable
  • 40GBASE-LR4
  • 40 Gb/s transmission speed
  • Baseband transmission
  • Over 4 wavelengths carried by a single long-distance single-mode fiber optic cable
  • 100GBASE-SR10
  • 100 Gb/s transmission speed
  • Baseband transmission
  • Over 10 short-range multi-mode fiber optic cable
  • 100GBASE-LR4
  • 100 Gb/s transmission speed
  • Baseband transmission
  • Over 4 wavelengths carried by a single long-distance single-mode fiber optic cable



  • Last modified: April 7, 2025