Asynchronous transfer mode
Asynchronous transfer mode (ATM),also known as cell relay,is in some ways similar to packet switching.Like packet switching,ATM involves the trans-fer of data in discrete chunks.Also,like packet switching,ATM allows mul- tiple logica connections to be multiplexed over a single physical inter- face,In the case of ATM, the information flow on each logical connection is organized into fixed-size packets,called cells.
ATM is a streamlined protocol with minimal error and flow control capabilities.This reduces the overhead of processing ATM cells and reduces the number of overhead bits required with each cell,thus enabling ATM to operate at high data rates.Further,the use of fixed-size cells simplifies the processing required at each ATM node,again supporting the use of ATM at high data rates.
ATM Logical Connections
异步传输模式
异步传输模式（Asynchronous Transfer Mode,ATM）又称为信元中继（cell relay），它在某种程度上与分组交换技术类似。与分组交换一样，ATM也使用不连续的数据块进行数据传输，并允许在单个物理接口上复用多条逻辑连接。在使用ATM时，每个逻辑连接上的信息流都被组织成固定大小的分组，称为信元（cell）。
ATM是一个合理化的协议,它具有最小的差错和通信控制能力。这样做是为了减小ATM信元处理的开销，同时也减小了每个信元所要求的开销比特的数量，因而使ATM能够以很高的数据率操作。再者，使用大小固定的信元可以简化ATM节点需要完成的工作，这样有助于ATM的高速运行。
