Networking —

802.2 IEEE Standard

The 802.2 standard, referred to as the Logical Link Control (LLC), manages data flow control and error control for the other IEEE LAN standards. Data flow control regulates how much data can be transmitted in a certain amount of time. Error control refers to the recognition and notification of damaged signals.

802.3 IEEE Standard

The IEEE 802.3 standard defines the characteristics for Ethernet networks. Ethernet networking is by far the most widely implemented form of local area networking. Several Ethernet LAN characteristics are identified in the 802.3 standard.

Since the development of the original 802.3 standards, there have also been several additions that have been assigned new designators. These standards are often referred to as the 802.3x standards. Some of the newer standards include 802.3u for Fast Ethernet, 802.3z for Gigabit Ethernet, and 802.3ae for 10-Gigabit Ethernet. The features for 802.3 are listed here:

  • Speed The original IEEE 802.3 standard specified a network transfer rate of 10Mbps. There have been modifications to the standard, the result being Fast Ethernet (802.3u), which can transmit network data up to 100Mbps and higher, as well as Gigabit Ethernet (802.3z), which can transmit at speeds up to 1000Mbps. 802.3ae is a very fast 803.3 standard. Known as 10-Gigabit Ethernet, it offers speeds 10 times that of Gigabit Ethernet.

  • Topology The original Ethernet networks used a bus or star topology because the original 802.3 standard included specifications for both twisted pair and coaxial cabling. The IEEE 802.3u and 802.3z specify twisted pair cabling and use a star topology. Remember that even when Ethernet uses a physical star topology, it uses a logical bus topology.

  • Media The media refers to the physical cabling used to transmit the signal around the network. The original 802.3 specifications identified coaxial and twisted pair cabling to be used. The more modern standards specify twisted pair and fiber-optic cable. 802.3ae currently only supports fiber media.

  • Access method The access method refers to the way that the network media is accessed. Ethernet networks use a system called Carrier Sense Multiple Access with Collision Detection (CSMA/CD). CSMA/CD works by monitoring the computers that are sending data on the network. If two computers transmit data at the same time, a data collision will occur. To prevent collisions, the systems sending the data will be required to wait a period of time and then retransmit the data to avoid the collision. 10-Gigbit Ethernet only operates in full-duplex mode and, as such, does not need to use the traditional Ethernet CSMA/CD access method.