Wired LANs : Ethernet

Ethernet

 

• One of the most widely used wired LAN technologies
• Operates in Data-Link-Layer and Physical Layer
• Family of networking technologies that are defined in the IEEE 802.2 and 802.3 standards
• Supports data band witdhs of 10, 100, 10,000, 40,000, and 100,000 (100Gbps)

 

Ethernet standards

 

• Define Layer 2 protocols and Layer 1 technologies
• Two separate sublayers of the data link layer to operate - Logical Link Control (LLC) and the MAC sublayers

 

Evolution of Ethernet

 

 

Ethernet frame format

 

 

• Preamble : Synchronization Purpose, 56bit of alternating 1s and 0s
• SFD : Delimiter and also synchronization. The last two bits indicate the receiver that the upcoming field is the destination address
• Destination address : Destination MAC address
• Source address : Source MAC address
• CRC : Error Detection

 

Unicast and Multicast address

 

• multicast address: the recipients are all the stations on the LAN. A broadcast destination address is forty-eight Is.

 

Changes in the Standard

 

Bridged Ethernet

 

 

• The more bridges are divided, the more the effects of the collision are dispersed.

 

Switched Ethernet

 

• Share Bandwidth all equally.
• Since it is connected to a switch, there is no effect on other domain because the collision occurs in an independent space.

 

Full-duplex switched Ethernet

 

• Full-duplex connection