ELECTROCARIAN

ATM virtual connections —   A Transmission path (TP) is the physical connection (wire,cable,satellite,and so on) between an end point and a switch or between two switches —   A Virtual Path (VP) transports ATM cells belonging to virtual channels which share a common identifier, called the Virtual Path Identifier VPI. Connects two switches. —   A Virtual Channel (VC) provides the transport of ATM cells which have the same unique identifier, called the Virtual Channel Identifier (VCI). ATM protocol reference model The Physical Layer •         This layer describes the physical transmission of information through an ATM network. •        The original design of ATM was based on SONET because  high data rate of SONET’s carrier , the boundaries of cells can be clearly defined . •         SONET specifies the use of pointer to define the beginning of a payload. •        Types of physical media specified for ATM include shielded and unshielded twisted-pair, coaxial cable, and fiber-optic