Basic Network Design

The most general form of network is Ethernet. This is a bus-like network which uses CMSA-CD (Carrier-Sense Multiple Access with Collision Detection). Within this network stations apply a voltage to the bus whenever they wish to send data, through sensing the bus for this voltage it is determined if the bus is in use. Several accesses imply in which several hosts might be on this bus. Collision detect is used to detect many hosts sending data at the similar time. Initially, it would seem unnecessary to required collision detection; after all, a station sends data on the bus whenever nothing is being sent. With Due to the propagation delay of electrical signals we can have stations which decide to send data at the similar time. Whenever every station looks at the bus it is clear. Moreover, before the data they send reaches its destination they will collide and the result will be garbage. A collision detection circuitry monitors the line to verify if there were no collisions and the data does not required to be re-sent.

Understanding the Carrier-Sense Multiple Access with Collision Detection concept is fundamental to understanding how ethernet works. Whole limitations search on the design of ethernet networks are due to issues surrounding Carrier-Sense Multiple Access with Collision Detection. The biggest design limitation is that reading data on an ethernet is a passive operation, the sending stations have no pathway to "sense" whenever this has happened. Moreover, the sending station must perform collision detection until that knows the receiving station has received the packet! To perform this task, lengthy restrictions have to be developed so in which a sending station knows which inside a finite time the receiving stations must have received the packet. This limitation controls most of the aspects of network design.