Introduction
- Ethernet was developed at Xerox PARC between 1973 and 1974.
- It was first standardized in 1983 as IEEE 802.3
Why Ethernet?
- To provide an Internet connection and connect devices to LAN (Local Area Network).
- Cost-effective.
Exploring IEEE 802.3 Ethernet Standards:
- IEEE 802 is for LAN technologies.
- 802.3i can transmit 10 Mbps.
- 802.3u can transmit 100 Mbps.
- 802.3ab can transmit 1 Gbps.
- 802.3an can transmit 10 Gbps.
Where 802.3an = 10 GBASE-T
- G - Gigabit per second.
- BASE —Baseband signaling.
- T — UTP (Unshielded Twisted Pair).
Why are the cables twisted?
- When an electric current flows through a wire, it creates a magnetic field around it (Electromagnetic induction).
- Twisting pairs of wires reduces electromagnetic interference (EMI)
- If the cable is twisted, crosstalk is reduced
Ethernet cabling standards
CAT 5 (category 5)
- Speed: 100 Mbps
- Bandwidth: 100 MHZ
- Distance: 100 m
CAT 5e (category 5 enhanced)
- Speed: 1 Gbps
- Bandwidth: 100- 250 MHz
- Distance: 100 m
CAT 6 (category 6)
- Speed: 10 Gbps
- Bandwidth: 250 MHz
- Distance: 37–55 m
CAT 6a (category 6 augmented)
- Speed: 10 Gbps
- Bandwidth: 500 MHz
- Distance: 100 m
CAT 7(category 7)
- Speed: 10 Gbps
- Bandwidth: 600 MHz
- Distance: 100 m
CAT 8.1(category 8.1)
- Speed: 25 Gbps
- Bandwidth: 2000 MHz
- Distance: 30 m
CAT 8.2(category 8.2)
- Speed: 40 Gbps
- Bandwidth: 2000 MHz
- Distance: 30 m
RJ45:
- RJ45 — Registered Jack-45
- RJ45 connectors are used to terminate the ends of Ethernet cables, allowing them to be plugged into network interfaces such as computers, switches, and routers.
Straight-through:
The wiring pinouts are identical on both ends of the cable.
Crossover:
The wiring pinouts on one end are reversed (swapped) compared to the other end.
Auto MDI-X:
- Auto Medium-Dependent Interface Crossover
- It automatically determines and adapts whether the connection cable is straight-through or crossover.
References:
- IEEE standard for Ethernet: 802.3–2018 — IEEE Standard for Ethernet | IEEE Standard | IEEE Xplore
- Ethernet cabling standards: Cat5, Cat6, Cat7 vs. Cat8: Which Cable is Right For You? (longrangesignal.com)