The objective was to implement an Ethernet Switch, initially capable of handling four computer nodes. The switch works in the Data-Link and Physical layers of the OSI network model, and conforming to the IEEE 802.3 Ethernet specifications. All nodes are capable of full duplex operation. The switch is a modified-cut-through type with dedicated memory for each input port and a common memory for the output ports. The look-up table for MAC addresses is designed to have a linear search algorithm for optimum speed.
An Ethernet switch is vastly superior to a conventional network hub. However, due to its high cost, it is not commonly used. In a typical small to medium scale Local Area Network (LAN), a hub is the preferred interconnection device due to its relatively low cost and ease of configuration. A hub, however, has a serious limitation – in a network of N machines, only one machine can transmit at a time.