Difference between Ethernet vs Fast Ethernet vs Gigabit Ethernet

This tutorial section on Ethernet basics covers following sub topics:
Ethernet over copper  Ethernet Business  Gigabit Ethernet  40Gbps Ethernet PHY   100Gbps Ethernet PHY   10Gbps Ethernet PHY   Ethernet types  

This page on Ethernet vs Fast Ethernet vs Gigabit Ethernet covers basic difference between Ethernet, Fast Ethernet and Gigabit Ethernet.


Normal ethernet works at 10Mbps speed. The Ethernet MAC technology is called CSMA/CD (carrier-sense multiple access with collision detection).

Following table mentions different 10 Mbps Ethernet such as 10BASE5, 10BASE2, 10BASE-F and 10BASE-T.

Specification 10BASE5 10BASE2 10BASE-F 10BASE-T
Maximum segment length 500 m 185 m varies from 400 m to 2000 m 100m
topology Bus Bus Star Star
medium 50-"omega" thick coax. 50-"omega" thin coax. multimode fiber 100-"omega" UTP
connector NICDB15 BNC ST RJ-45
Medium attachment MAU bolted to coax ethernal or on NIC External or on NIC External or on NIC
stations/cable segment 100 30 N/A 2(NIC, repeater)
Maximum 5 5 5 5 segments

There are two types of ethernet half duplex and full duplex.

Following are the Ethernet MAC parameters:
Slot time: 512 bit times
Min. Interframe Gap: 96 bit times
Attempt Limit: 16 (tries)
Backoff limit: 10 (exponential number)
JamSize: 32 bits
Max. Frame Size: 1518 bytes
Min. Frame Size: 64 bytes (512 bits)
Address Size: 48 bits

Fast Ethernet-802.3u

The ethernet working at the speed of 100Mbps is referred as fast ethernet. IEEE standard 802.3u fast ethernet/100BASE-T specified in May1995. The features of this type of fast ethernet are as follows:
• Includes multiple PHY layers.
• It uses original ethernet MAC but operates at 10 times higher speed.
• It needs star wired configuration with central hub.

The MAC parameters are same as described for ethernet above. There are three physical layers for fast ethernet.
• 100BASE-TX: Needs 2 pairs of cat.5 UTP/Type1 STP cables
• 100BASE-FX: Needs 2 strands of multimode fiber
• 100BASE-T4: Needs 4 pairs of cat.3 or any better cables

Following table-2 summarizes different versions of 100BASE-T physical layers.

Specification 100BASE-Tx 100BASE-Fx 100BASE-T4
IEEE standard 802.3u-1995 802.3u-1995 802.3u-1995
Encoding 4B/5B 4B/5B 8B/6T
cabling UTP cat.5 or STP Multimode or single mode fiber UTP cat.3/4/5
signal frequency 125 MHz 125 MHz 25 MHz
No. of pairs needed 2 2 4
No. of transmit pairs 1 1 3
distance 100m 150/412/2000 m 100m
Full duplex capabilities Yes Yes No

Gigabit Ethernet-802.3z

The ethernet working at the speed of 1000Mbps (i.e. 1Gbps) and above is referred as Gigabit ethernet.

Gigabit Ethernet uses 802.3 frame format same as 10Mbps ethernet and 100Mbps fast Ethernet It also operates in half duplex and full duplex modes. There are various Gigabit ethernet versions which operates at 1 Gigabit, 10 Gigabit, 40 Gigabit and 100 Gigabit per second speeds.

There are various versions for 10 Gbps ethernet such as 10GBASE-T, 10GBASE-R, 10GBASE-X and 10GBASE-W. Read more.

MAC parameters for gigabit ethernet are same as mentioned above in ethernet. Except slot time which is 512 byte times.

10, 40, 100 Gigabit Ethernet Physical Layers

Refer following links to navigate articles on 10, 40 and 100 Gigabit Ethernet Physical Layers.
10 Gigabit Ethernet Physical Layer
40 Gigabit Ethernet Physical Layer
100 Gigabit Ethernet Physical Layer

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Ethernet tutorial   Thicknet vs Thinnet  Broadband vs Baseband LAN  Ethernet over copper  Ethernet Business  LAN vs WAN vs MAN   What is MAC Address   Gigabit Ethernet  10 Gigabit Ethernet PHY   40 Gigabit Ethernet PHY   100 Gigabit Ethernet PHY 

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