|
A collision is the situation that occurs when two or more devices attempt to send a signal along the same transmission channel at the same time. The colliding of the signals can result in garbled, and thus useless, messages. All computer networks require some sort of mechanism to either prevent collisions entirely or to recover from them when they occur. A transmission channel is the path between two nodes (i.e., devices) on a network that data communication follows. The term can refer to the physical (i.e., copper wire or optical fiber) cabling or radio wave frequency that connects the nodes, the signal that is communicated over the pathway, or a subchannel in a carrier frequency. In ethernet networks, the dominant type of local area network (LAN), collisions occur when two nodes attempt to send packets simultaneously. This can cause loss of the data and require retransmission. Collisions are considered normal events in ethernets, and the CSMA/CD (carrier sense multiple access/collision detection) protocol is designed to quickly restore the network to normal activity and use a built-in delay algorithm to make certain that the collision does not reoccur. A collision domain is a logical area in a network in which packets can collide with one another. It is delimited by routers and network switches, and it can be comprised of a single segment of cable in an ethernet network or it can include numerous repeaters and hubs.
Created September 29, 2005. |