Ethernet is one of the widely used local area network (LAN) technology.

  1. Switched Ethernet
  2. Fast Ethernet
  3. Gigabit Ethernet

Switched Ethernet

  • Switched Ethernet gives dedicated 10 Mbps bandwidth on each of its ports.
  • On each of the ports, one can connect either a thick/thin segment or a computer.
  • In Switched Ethernet, the collision domain is separated.
  • The hub replaced by a switch, which functions as a fast bridge.
  • It can recognize the destination address of the received frame and can forward the frame to the port to which the destination station is connected.
  • The other ports not involved in the transmission process.
  • The switch can receive another frame from another station at the same time and can route this frame to its own final destination.
  • In this case, both the physical and logical topologies are the star.
  • The throughput can further increased on switched Ethernet by using the full-duplex technique, which uses separate wire pairs for transmitting and receiving.
  • Thus a station can transmit and receive simultaneously, effectively doubling the throughput to 20 Mbps on each port.

Fast Ethernet

  • The 802.u or the fast Ethernet, as it is commonly known, was approved by the IEEE 802 Committee.
  • The fast Ethernet uses the same frame format, same CSMA/CD protocol and same interface as the 802.3, but uses a data transfer rate of 100 Mbps instead of 10 Mbps.
  • However, fast Ethernet based entirely on 10-Base-T, because of its advantages ( Although technically 10-BASE-5 or 10-BASE-2 can use with shorter segment length ).
  • IEEE has designed two categories of Fast Ethernet: 100Base-X and 100Base-T4.
  • 100Base-X uses two-wire interface between a hub and a station while 100Base-T4 uses four-wire interface.
  • 100-Base-X itself divided into two: 100Base-TX and 100base-FX
  • Upgrade the data rate to 100 Mbps.
  • Make it compatible with Standard Ethernet.
  • Keep the same 48-bit address.
  • Also, Keep the same frame format.
  • Keep the same minimum and maximum frame lengths.

Gigabyte Ethernet

  • The technology based on fiber optic cable. Multi-mode fiber is able to transmit at gigabit rate to at least 580 meters and with single-mode runs exceeding 3 km.
  • Fiber optic cabling is costly. In order to reduce the cost of cabling, the 802.3z working group also proposed the use of twisted pair or cable or coaxial cable for distances up to 30 meters.
  • Also, At gigabit speed, two stations 200 meters apart will not detect a collision, when both simultaneously send 64-byte frames.
  • This inability to detect collision leads to network instability.
  • Moreover, A mechanism known as carrier extension has proposed for frames shorter than 512 bytes.
  • The number of repeater hops also restricted to only one in place of two for 100 Base-T.
  • Upgrade the data rate to 1 Gbps.
  • Make it compatible with Standard or Fast Ether net.
  • Also, Use the same 48-bit address.
  • Use the same frame format.
  • Keep the same minimum and maximum frame lengths.
  • To support auto-negotiation as defined in Fast Ethernet.