IEEE which stands for the institute of electrical and electronics engineers states that 802.3 standard refers to a set of protocols which defines the local area networks (LAN). These standards cover the operation, bandwidth and connections of devices in a LAN setting.
There are two distinct LAN operations. One is called the half-duplex mode can be compared to the use of a walkie-talkie-phone. It has the ability to receive and send data one direction at a time. The other is referred to as the full-duplex mode. This mode has the capability to send and receive data simultaneously. This mode is the most popular Ethernet mode used.
There are four data rates for the 802.3 standard. They are defined by the speed of which the data can be transmitted through the networks that are connected by physical cables. The first of which is the Ethernet. This has a speed of 10 Mbps. The next is referred to as the Fast Ethernet also called the IEEE 802.3u protocol. The speed of this data rate is 100 Mbps.
The third is the Gigabit Ethernet also referred to as the IEEE 802.3z. The data speed of this third protocol is 1000Mbps. The final protocol is the 10Gbps Ethernet also referred to as the 802.3ae. As the name suggests, the speed of this protocol is 10 Gbps.
The connection cables are what will determine the speed of your data transfer ability. If you are using Twisted pairs cables also referred to as coaxial cables you will only be able to use up to 802.3u protocol. This connection is more commonly used due to the fact that it is more reliable over long distances. For faster data transfers you can use Fiber-optic cable connections. These cables will allow for the use of data speeds greater then 100Mbps limits of the coaxial cables.