Ethernet is a family of networking technologies used for local area networks (LANs). It was introduced in 1980 and standardized in 1985, providing data link layer services divided into logical link control and media access control sublayers. Ethernet has evolved to support higher data rates up to 10 Gbps while maintaining compatibility through consistent frame formats and addressing. Fiber optic and twisted pair cable implementations allow Ethernet to scale from campus to wide area networks.

2.  Ethernet is a family of computer
networking technologies for local area
networks (LANs).
 Introduced in 1980 and standardized in 1985 as IEEE
Standard Project 802.3.

3.  Ethernet provides services up to and including
the data link layer which is divided into 2 sublayers:
LLC & MAC.
 Logic Link Control: Provides interconnectivity
between different LANs.
 Media Access Control: Frames data received from
the upper layer & passes to the physical layer.
 Physical Layer: It defines transmission of raw bits
rather than data packets.

7.  10Base5: Max Length=500m, uses bus topology.
 10Base2: Max Length is roughly 185m. Very flexible.
Uses a bus topology too.
 10Base-T : Connected to a hub via 2 twisted cables.
Uses a star topology. Max Length=100m.
 10Base-F :Connected to a hub via 2 fiber optic
cables. Uses a star topology. Max Length=2000m.

8. Fast Ethernet
100 BASE-TX 100 BASE-FX 100 BASE-T4

10. The goals of the above are:
 Upgrade the data rate to 100Mbps.
 Make it compatible with Standard Ethernet.
 Keep the same 48-bit address.
 Keep the same frame format.
 Keep the same minimum & maximum frame lengths.

11.  100Base-TX uses 2 Twisted Pair
cables.
 Good Bandwidth.
 100Base-T4 uses 4 pairs of
Unshielded Twisted Pair cables.
This is cost efficient.

12.  100Base-FX uses 2 pairs of Fiber optic cables. Higher
Bandwidth.
 Uses 1300 nm near infrared wavelength
 Max length
◦ 412 m for half duplex.
◦ 2 kms for full duplex.

13. Gigabit Ethernet
Implementations
1000 BASE-
SX
1000 base-
LX
1000BASE-
CX
1000 BASE-T

14. The goals of the above are:
 Upgrade the data rate to 1Gbps.
 Make it compatible with Standard or Fast Ethernet.
 Use the same 48-bit address.
 Use the same frame format.
 Keep the minimum & maximum frame lengths.

17.  Upgrade the data rate to 10Gbps.
 Make it compatible with Standard, Fast & Gigabit
Ethernet.
 Use the same 48-bit address.
 Use the same frame format.
 Keep the same minimum & maximum frame lengths.

18.  Allow the interconnection of existing LANs into a
Metropolitan Area Network (MAN) or a Wide Area
Network (WAN).
 Make Ethernet compatible with technologies like
Frame Relay & ATM.

20.  Classification:
◦ 1. Single mode fiber (SMF)
◦ 2. Multi mode Fiber (MMF)
 Single mode: Light follows a single path
 Multi mode: Light follows multiple path leading to
differential mode delay.