Evolution and Standards of Ethernet Technology: From 10 Mbps to 100 Gbps

With the rise of cloud computing and software‑defined networking, Ethernet has undergone major technological transformations in reliability and speed. This article reviews Ethernet development, starting from the original medium standards.

1973: Xerox introduced Ethernet at 2.94 Mbps.

1980: DIX 10 Mbps Ethernet standard by DEC, Intel, Xerox.

1995: IEEE 802.3u Fast Ethernet (100 Mbps).

1998: IEEE 802.3z Gigabit Ethernet.

1999: IEEE 802.3ab 1000BASE‑T (Gigabit over twisted‑pair).

2002: IEEE 802.3ae 10 GbE (10GBASE‑R, 10GBASE‑W, 10GBASE‑LX4).

2004: IEEE 802.3ak 10GBASE‑CX4 copper standard.

Early Ethernet used shared coaxial media (10BASE5 and 10BASE2). Connecting devices required a tap, which posed a risk of shorting the cable core and causing network failure.

Twisted‑pair cables are divided into shielded (STP) and unshielded (UTP). UTP is classified into seven categories (EIA/TIA‑568‑A), with Category 5 (Cat‑5) being the most common for data transmission.

Wiring standards 568A and 568B define the color order of the eight conductors in an RJ45 plug. A straight‑through cable uses the same standard on both ends, while a crossover cable mixes 568A on one end with 568B on the other.

Standard Ethernet (10 Mbps) positioning

10 Mbps Ethernet is typically used at the access layer and supports up to 100 m of cabling.

Fast Ethernet (100 Mbps) positioning

Fast Ethernet provides higher bandwidth for desktops and servers, defined by IEEE 802.3u, and operates in full‑duplex mode to eliminate collisions.

Gigabit Ethernet

Gigabit Ethernet extends IEEE 802.3 with 1 Gbps speed, using standards 802.3z (fiber and copper) and 802.3ab (twisted‑pair). It supports 1000BASE‑LX (long‑wave laser), 1000BASE‑SX (short‑wave laser), 1000BASE‑CX (shielded copper), and 1000BASE‑T (Category‑5 UTP up to 100 m).

Many aggregation‑layer switches provide Gigabit ports for inter‑switch links and stacking, though stacking implementations are often vendor‑specific.

Ethernet auto‑negotiation

When Ethernet speeds increased to 100 Mbps, auto‑negotiation was introduced to ensure compatibility with legacy 10 Mbps devices. The protocol exchanges 16‑bit messages to advertise supported speeds, duplex modes, and flow‑control options, and can fall back to Normal Link Pulse (NLP) for 10BASE‑T compatibility.

Auto‑negotiation also supports extended pages for additional capabilities, using message pages and unformatted pages to convey extra information.

Fiber optic connectors and modules

Fiber connectors (FC, SC, LC, ST, MTRJ) are classified by polishing method: flat (FC), PC, or APC. Optical modules come in SFP/ESFP, SFF, GBIC, and 1×9 SC formats, supporting single‑mode and multimode fibers at wavelengths such as 850 nm, 1310 nm, and 1550 nm, and various transmission distances (2 km to 80 km).

Key fiber parameters include dispersion, attenuation, bandwidth, cutoff wavelength, and numerical aperture, with dispersion and attenuation being the most critical for system design.

For further reading, see the linked articles on the OpenPower Foundation and NVMe over Fabrics.