what is Gigabit Ethernet?
Ethernet has evolved over the years from 10 Mbps to 100 Mbps to 1000Mbps. Ethernet with 100 Mbps speed is referred as Fast Ethernet. The type of ethernet which supports 1000 Mbps or 1 Gbps over fiber and copper is referred as Gigabit Ethernet.
This version of ethernet is most popular is defined in IEEE 802.3z and IEEE 802.3ab standards. They are referred as 1000 Base-X and 1000Base-T respectively. CSMA/CD access is used here and max. Following table-1 summarizes gigabit ethernet standards with maximum cable length supported with cable type.
It supports CSMA/CD protocol in half duplex mode for communication between peer PCs connected on LAN. It supports SNMP tools.
Traditional ethernet frame size is about 64 to 1518 bytes and jumbo frame size is about 64-9215 bytes. Gigabit ethernet exploits jumbo frame and reduces the ethernet frame rate to end host PC. Here collisions and waiting period is less compare to 10Mbps ethernet version as it requires less time to transmit the frame from source node to the destination node.
|Ethernet Standard||MAC sub-layer specification||Max.cable length||Cable Type supported||Pairs needed|
|1000Base-SX||802.3z||220 to 550 meter||multimode fiber||1|
|1000Base-LX||802.3z||3000 meter||single mode OR multimode fiber||1|
|1000Base-CX||802.3z||25 meter||Shielded copper||2|
|1000Base-T||802.3ab||100 meter||Category 5 UTP (twisted pair)||2|
Gigabit version of ethernet 802.3z is introduced in the year 1998,IEEE 802.3ab in 1999 and IEEE 802.3ae referred as 10 Gigabit ethernet has been introduced in 2002.
10 Gigabit Ethernet
This type of ethernet is introduced in the year 2002. It is defined in IEEE 802.3ae specifications. As the frame size used is same, no change is needed to layer-3 and higher protocols.
This 10 Gigabit ethernet operates on point to point link only in full duplex mode. This standard specifies two physical layer verisons viz. LAN PHY and WAN PHY. They are used for physical layer network applications. WAN PHYSICAL layer provide support for connections to circuit switched based SONET networks.
10 Gigabit Ethernet supports seven interfaces as mentioned in the table-2.
|Interface||PHY version||Optical wavelength|
|10GBASE-LX4||LAN||4-Channel course wave division multiplexing (CWDM), 4x1310nm|
10GBASE-R uses 64B/66B encoding system and runs at 10.313Gbps while 10GBASE-X uses 8B/10B encoding and runs at 3.125Gbps after encoding scheme.