1. Field of the Invention
The invention relates to the field of digital circuitry. More specifically, the invention relates to a cross-connect.
2. Background of the Invention
The current explosion of data traffic traversing the public network is forcing the carriers to change their approach when designing their networks. Time Division Multiplexing (TDM) networks have a place in the telecommunications network, as certain customers require the reservation of portions of bandwidth within the network. The telecommunication industry has sought to maximize the data throughput by developing techniques allowing for the simultaneous transmission of multiple channels on a single telecommunications medium. Data multiplexing is not new to the industry, but introducing new methods in their design are certainly welcomed.
A typical TDM network element includes a number of line cards. Data enters and exits the network element through these line cards. The line cards are coupled to a cross-connect that allows for traffic to be selectively transmitted from any of the line cards to any of the other line cards. Thus, the TDM traffic is aligned and switched through the cross-connect.
A typical cross-connect includes three modules: 1) an input Time Slot Interchange (TSI); 2) a switch; 3) and an output TSI. The traffic of each of the line cards is provided to the input TSI. The input TSI includes a buffer for each line card that can reorder the incoming data into a different sequence and/or selectively store parts of it. The output TSI also includes a buffer for each line card. The switch is controlled to selectively provide the output of any one of the buffers in the input TSI to be provided to any one of the buffers of the output TSI. Similar to the buffers of the input TSI, the buffers of the output TSI can selectively reorder and/or selectively store the data. Thus, the buffer of the output TSI can intermix the data from different line cards when the switch and output TSI are so controlled.
A limitation of this prior art method is that it necessitates relatively larger amounts of memory of a type that is typically operated at lower frequencies.