| 摘要 |
A method and apparatus are provided to remove dataless TDM frames when transporting private line traffic over an ATM network. A number of TDM frames comprising a TDM private line circuit are received, and it is determined if a TDM frame contains data. The determination may be based on, for example, the detection of one or more frame delimiters, such as by comparing information in the TDM frame with a pre-determined frame delimiter pattern. Information from the TDM frame is placed into an ATM cell only when the TDM frame contains data. An indication that a TDM frame has not been placed into an ATM cell is conveyed in the AAL2 headers. A first plurality of TDM private line circuits, such as T1 circuits, may be multiplexed into a first real time variable bit rate (rt-VBR) virtual circuit, and a second plurality of TDM private line circuits may be multiplexed into a second rt-VBR virtual circuit, such that the bandwidths of the first and second rt-VBR virtual circuits are not limited, such as by using AAL2 multiplexing with substantially large SCR, PCR and MBS values. The first and second rtVBR virtual circuits may then be combined for transport over the ATM network link, and an indication that a TDM frame without data has not been transported is used to re-insert the dataless TDM frame.
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