Method, apparatus and computer program product for interfacing a TDM link with a cell-switched network

A cell transmitter at a first node, comprising:

• means for removing one or more idle timeslots from TDM frames to form compressed TDM frames;
• wherein each of said compressed TDM frames comprises one or more active timeslots;
• means for inserting one or more compressed TDM frames into a data cell, the means for inserting one or more compressed TDM frames comprising means for inserting an integer number of compressed TDM frames into the data cell;
• means for transmitting the data cell to a second node;
• and
• a processor for controlling said means for removing and said means for inserting based on a channel status message.

A cell transmitter at a first node, comprising:

• means for removing one or more idle timeslots from TDM frames to form compressed TDM frames, wherein each of said compressed TDM frames comprises one or more active timeslots;
• means for inserting one or more compressed TDM frames into a data cell;
• means for inserting a spare bit field in said data cell when an integer number of compressed TDM frames does not completely occupy a capacity of said data cell;
• means for transmitting the data cell to a second node;
• and
• means for controlling said means for removing and said means for inserting based on a channel status message.

A cell receiver at a second node, comprising:

• means for receiving a data cell;
• means for unloading one or more compressed TDM frames from said data cell;
• means for adding one or more idle timeslots to each compressed TDM frame to restore said one or more compressed TDM frames to one or more TDM frames;
• and
• a processor for controlling said means for unloading and said means for receiving based on a channel status message.

A computer program product comprising a computer usable medium having computer program logic stored therein for interfacing a TDM link with a cell-switched network at a first node, wherein the computer program logic comprises:

• receiving means for enabling a computer to receive a channel status message that identifies one or more active channels and one or more idle channels;
• determining means for enabling said computer to determine a cell structure based on said channel status message that maximizes a number of compressed TDM frames that may be carried by a data cell;
• assigning means for enabling said computer to assign a data address to said cell structure;
• removing means for enabling said computer at the first node to remove one or more idle timeslots from TDM frames to create compressed TDM frames;
• wherein each of said compressed TDM frames comprises one or more active timeslots;
• inserting means for enabling said computer to insert one or more compressed TDM frames into the data cell;
• and
• sending means for enabling said computer to send said data cell over the cell-switched network to a second node.

A computer program product comprising a computer usable medium having computer program logic stored therein for interfacing a TDM link with a cell-switched network at a second node, wherein the computer program logic comprises:

• receiving means for enabling a computer to receive a data cell from a first node;
• unloading means for enabling said computer to unload one or more compressed TDM frames from said received data cell;
• adding means for enabling said computer to add one or more idle timeslots to each compressed TDM frame unloaded from said received data cell to restore said one or more compressed TDM frames to one or more TDM frames;
• controlling means for controlling said unloading means and said adding means based on a channel status message;
• and
• sending means for enabling said computer to send said one or more restored TDM frames to a DTE.

A system for interfacing a T1 link with an Asynchronous Transfer Mode (ATM) network at a first node and a second node, where the T1 link supplies T1 frames comprising at least one active timeslot and at least one idle timeslot, and where each active timeslot carries a sample of a corresponding active channel and each idle timeslot carries a sample of a corresponding idle channel, the system comprising:

• receiving a channel status message at the first node that identifies each active channel and each idle channel of the T1 link;
• determining a cell structure based on the channel status message that maximizes a number of compressed T1 frames that may be carried by a data cell;
• means for removing one or more idle timeslots from T1 frames to create compressed T1 frames, based on the channel status message, wherein each compressed T1 frame comprises one or more active timeslots;
• means for inserting one or more compressed T1 frames into the data cell;
• and
• means for sending said data cell over the ATM network from the first node to the second node.

A port card for interfacing a TDM link with a cell-switched network at a first node, comprising:

• a data transmit buffer for receiving TDM frames from the TDM link;
• a cell transmitter for converting said TDM frames in said data transmit buffer to compressed TDM frames, and sending said compressed TDM frames over the cell-switched network to a second node in a data cell, wherein the cell transmitter comprises:
• a frame compressor for removing one or more idle timeslots from said TDM frames to create said compressed TDM frames, wherein each of said compressed TDM frames comprises one or more active timeslots,
• a cell payload generator for loading one or more compressed TDM frames in a payload of said data cell according to a predefined cell structure, wherein the cell structure is based on a channel status message that identifies at least one of one or more active channels and one or more idle channels, and
• a cell header generator for adding a cell header to said data cell payload;
• wherein said cell header carries a data address that identifies said cell structure of said data cell payload;
• and
• a compression module for controlling said frame compressor based on said channel status message, and for controlling said cell header generator based on said cell structure.

A port card for interfacing a TDM link with a cell-switched network at a first node, comprising:

• a data transmit buffer for receiving TDM frames from the TDM link;
• a cell transmitter for converting said TDM frames in said data transmit buffer to compressed TDM frames, and sending said compressed TDM frames over the cell-switched network to a second node in a data cell, wherein the cell transmitter comprises:
• a frame compressor for removing one or more idle timeslots from said TDM frames to create said compressed TDM frames, wherein each of said compressed TDM frames comprises one or more active timeslots,
• a cell payload generator for loading one or more compressed TDM frames in a payload of said data cell based on a channel status message that identifies at least one of one or more active channels and one or more idle channels, and
• a cell header generator for adding a cell header to said data cell payload;
• wherein said cell header carries a data address that identifies a cell structure of said data cell payload;
• and
• a com module for creating an overhead message to communicate said data address to said second node.

A port card for interfacing a TDM link with a cell-switched network at a first node, comprising:

• a cell receiver for receiving a data cell that has traveled over the cell-switched network from a second node, and for creating one or more TDM frames from said data cell, wherein the cell receiver comprises:
• a frame unloader for unloading one or more compressed TDM frames from said data cell,
• a frame expander for adding one or more idle timeslots to each compressed TDM frame unloaded from said data cell to restore said one or more compressed TDM frames to one or more TDM frames, and
• a header reader for reading a header of said data cell, wherein said data cell header contains a data address that identifies a cell structure of said data cell and wherein
• the frame unloader unloads the one or more compressed TDM frames from said data cell according to said cell structure;
• a data receive buffer for sending said one or more TDM frames to a DTE on the TDM link;
• and
• an expansion module for controlling said frame unloader and said frame expander.

A method of interfacing a time domain multiplexed (TDM) link with a cell-switched network, the method comprising:

• receiving a channel status message at a first node that identifies at least one of each active channel and each idle channel in the TDM link;
• removing one or more idle timeslots from TDM frames, based on the channel status message, to create compressed TDM frames;
• inserting one or more compressed TDM frames into a data cell;
• and
• sending the data cell over the cell-switched network from the first node to the second node.