· ATM network uses fixed-length cells to transmit information. The cell consists of 48 bytes of payload and 5 bytes of header. Transmitting the necessary number of cells per unit time provides the flexibility needed to support variable transmission rates.
· ATM network is connection-oriented. It sets up virtual channel connection (VCC) going through one or more virtual paths (VP) and virtual channels (VC) before transmitting information. The cells is switched according to the VP or VC identifier (VPI/VCI) value in the cell head, which is originally set at the connection setup and is translated into new VPI/VCI value while the cell passes each switch.
· ATM resources such as bandwidth and buffers are shared among users, they are allocated to the user only when they have something to transmit. The bandwidth is allocated according to the application traffic and QoS request at the signaling phase. So the network uses statistical multiplexing to improve the effective throughput.
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