2008 Oct 18
Asynchronous Transfer Mode is a connection-oriented network topology used for both LAN and WAN. An ATM network has one or more high-speed switches that each connect to computers and to other ATM switches. Usually optical fibers are used. The lowest layers of an ATM network use fixed sized frames called cells. Each cell is 53 octest long: 5 octets of header plus 48 octets of data.
ATM connection-oriented service is similar to switched telephone service, where a path through the network must be established for a connection. Once a connection has been established, the local ATM switch selects and identified for the connection, and passes the connection identifier to the computer along with a message that informs the computer of succes. The computer uses this connection identifier when sending orreciving cells.
When it finishes using a connection, the computer communicates with the ATM switch to request that the connection be broken. The switch then disconnects the two computers (similar to hangup a telephone). Connection identifiers can be reused.
2005-2008