Originally, each message that was sent within a network went to all connected devices. These then had to filter through all received data and decide whether it was relevant to them. This common bus enabled broadcast messages, but also recorded all data traffic for each member – clearly a security gap of early Ethernet. Data could be encrypted, but data traffic itself couldn’t be individually controlled. Hubs also couldn’t close this security gap. Bridges and switches are a solution in modern networks, as they can be used to segment the Ethernet.
This technology doesn’t solve all problems, though. Abuse by MAC flooding or MAC spoofing, for example, still poses a danger for the stability of the network and the security of the communicated data packages. Working securely with Ethernet therefore requires serious use of all connected systems and regular data analysis (e.g. LAN analysis) to uncover potential cases of misuse or disturbances.
As long as an Ethernet’s data amount isn’t at capacity, it functions well. Capacity utilization rates of more than 50 percent can cause data jams, though. As personal computers developed technologically and continuously increased their data volume, Ethernet networks also had to develop further to keep pace with the progress of technology. Switches are responsible for efficiently dividing data packages and minimizing the risk of collisions. Modern cable technologies like twisted pair and fiber optic have higher transfer rates meet the modern requirements for a network.
Another innovation is ‘Ethernet flow control’. With this mechanism, data transfer can temporarily be stopped to alleviate data flow from another location. This is especially practical in full-duplex mode when a network serves a relatively high number of end devices. The flow control for specific members of the network is temporarily cut off to optimize the overall reliability of the network. This can also cause losses in speed, though, which can then be stemmed by other mechanisms such as the transmission control protocol.
In the past, Ethernet primarily used conventional coaxial cables. Today, twisted pair copper cables and fiber optical cables are the industry standard, as they enable much faster transfer rates and a larger range. Another advantage is that copper cables can also supply power to connected devices. This method, called ‘power over Ethernet’ (PoE), is specified in IEEE 802.3af and enables energy-efficient networks.