Telecommunications apparatus and method

A method for transporting packets having either of isochronous units of payload data and asynchronous units of payload data, between receiving ports and transmitting ports, comprising the steps of:

• asynchronously queuing received packets from the receiving ports for time division multiplex (TDM) transmission toward a transmitting port of destination;
• reordering a sequence the isochronous units having been queued, into a second sequence, for TDM transmission during a frame period toward a transmitting port of destination;
• TDM transmitting the asynchronous units in packets and the reordered isochronous units in packets toward the transmitting ports of destination;
• whereby the isochronous units of payload data are time switched during transport between the receiving ports and the transmitting ports.

A telecommunications facility for transporting data packets having headers and payloads between a plurality of input ports and a plurality of output ports, comprising;

• a concentrator for receiving data packets from the plurality of input ports and for multiplexing the payloads into an incoming data stream and multiplexing the headers into an incoming header stream;
• a distributor for directing outgoing headers from an outgoing header stream along with respective payloads from an output data stream to those of a plurality of output ports to which the data packets are destined;
• a memory controller being responsive to information contained in the headers in the incoming header stream, for generating queue control information for relating each data packet to one of the plurality of output ports, for generating the outgoing headers in the outgoing header stream for data packets destined for any of the plurality outport ports, and for generating scheduling information;
• a buffer for receiving the incoming data stream and being responsive to the queue control information for queuing the payload of each related data packet into a queue associated with the output port for which the payload is destined, and for subsequently selecting and transferring queued payload data units of each data packet into an intermediate data stream;
• timeslot switching means for receiving a frame of payloads from the intermediate data stream and in response to timeslot switching information, for reordering data units from selected payloads into a switched data stream, and in response to the scheduling information from the controller for multiplexing reordered data units of a preceding frame of payloads from the switched data stream with the unselected payloads of data from the intermediate data stream into the outgoing data stream.

A method for transporting data packets having headers and payloads between a plurality of input ports and a plurality of output ports, comprising the steps of;

• receiving data packets from the plurality of input ports and multiplexing the payloads into an incoming data stream and multiplexing the headers into an incoming header stream;
• generating queue control information for relating each received data packet to one of the plurality of output ports, in response to information contained in the headers in the incoming header stream;
• selecting and queuing the payloads of data packets from incoming data stream into queues associated with the output ports for which the payloads are destined, subsequently selecting and transferring queued payload data units of each data packet into an intermediate data stream, in response to the queue control information;
• in response to information contained in the headers in the incoming header stream generating an outgoing header stream of outgoing headers;
• receiving a frame of payloads data units from the intermediate data stream and in response to timeslot switching information, reordering selected data units in the frame into a switched data stream;
• multiplexing the unselected payloads of data from the intermediate data stream with payloads of a preceding frame from the switched data stream into an output data stream;
• and
• a distributing outgoing headers from the outgoing header stream in association with respective payloads from the output data stream to at least one port of a plurality of output ports for which the payloads are destined.

A method of operating a telecommunications switching facility for receiving and transmitting ATM cells having either of isochronous payload data and asynchronous payload data between a plurality of ATM ports;

• the method comprising the steps of:
• receiving incoming headers from the plurality ATM ports in a predefined cyclic order;
• serially transferring incoming payload octets of incoming ATM cells from receiving ones of the plurality of ATM ports into receive TDM timeslots exclusively preallocated to each of the ATM ports,
• elastically queuing cell payloads from the receive TDM timeslots and subsequently reading octets of the elastically queued cell payloads into intermediate TDM timeslots being exclusively preallocated to each of the ATM ports;
• accepting the payload octets in a sequence in which said payload octets appear in the intermediate TDM timeslots, throughout a predefined periodic frame occurrence, and presenting selected ones of said octets in a reordered sequence in isochronous TDM timeslots;
• multiplexing octets from either of the intermediate TDM timeslots and the isochronous TDM timeslots, into transmit TDM timeslots;
• generating outgoing header octets, in response to those of the incoming headers which meet predetermined parameters, into header TDM timeslots, in synchronism with the transmit TDM timeslots;
• serially transferring payload octets from the transmit TDM timeslots and header octets from the header TDM timeslots to the respective payload and header portions of an outgoing ATM cell for which the payload octets are destined;
• whereby a data sample of an isochronous payload having been received in one of the payload octets of an ATM cell during one of said periodic frame occurrences is retransmitted in a selectable one of the payload octets of a full frame of octets within a following periodic frame occurrence.

A telecommunications switching facility for receiving and transmitting ATM cells having either of isochronous payload data and asynchronous payload data between a plurality of ATM ports;

• the telecommunications switching facility comprising;
• a receive TDM bus for transporting payload octets from ATM cells in time division multiplexed (TDM) frame defined timeslots;
• an intermediate transfer bus for transporting payload octets destined for ATM cells in TDM frame defined timeslots;
• a transmit TDM bus for transporting payload octets to ATM cells in TDM frame defined timeslots;
• a receive header bus for transporting header octets from ATM cells;
• a transmit header bus for transporting header octets to ATM cells;
• an asynchronous buffer having a plurality of FIFO queue elastic storage functions for queuing cell payloads from the receive TDM bus, and for reading octets of cell payloads from the elastic storage queuing functions onto the intermediate transfer bus;
• switch means for accepting the payload octets in a sequence in which said payload octets appear on the intermediate transfer bus, throughout a predefined periodic frame occurrence, and for presenting selected ones of said octets in a reordered sequence throughout a subsequent one of the predefined periodic frame occurrences via an isochronous payload bus;
• multiplexing means for passing octets from either of the intermediate transfer bus and the isochronous payload bus, into the TDM frame defined timeslots of the transmit TDM bus
• an access unit including;
• incoming header transfer means for transferring header octets from the plurality ATM ports to the receive header bus in a predefined cyclic order,
• a control means being responsive to a header from the receive header bus, which meets predetermined parameters, for transmitting a header onto the transmit header bus;
• outgoing header transfer means for transferring header octets from the transmit header bus to the plurality of ATM ports in a predefined cyclic order,
• incoming payload transfer means for serially transferring payload octets of incoming ATM cells from receiving ones of the ATM ports into receive TDM bus timeslots exclusively preallocated to each of the ATM ports, and
• outgoing payload transfer means for serially transferring payload octets destined for outgoing ATM cells from transmit TDM bus timeslots exclusively preallocated to each of the ATM ports;
• whereby a data sample of an isochronous payload having been received in one of the payload octets of an ATM cell during one of said periodic frame occurrences is retransmittable as any one of the payload octets of a full frame of octets within a next following periodic frame occurrence.

A telecommunications switching facility comprising;

• a memory controller;
• a plurality of ports (511-519) for receiving and transmitting ATM cells having either of isochronous payload data and asynchronous payload data and;
• an asynchronous buffer (560) for queuing a received ATM cell in relation to a destination one of the plurality of ports and for transmitting the queued cell at a time designated for receipt at the destined one of the ports in response to addressing and control signals from the memory controller;
• switch means (520) being responsive to payload data having been transmitted from the asynchronous buffer during a frame period (125 .mu.s), for storing the payload data in a first sequence of data storage locations;
• and for reproducing said stored data in second sequence, wherein one of the first sequence and the second sequence is of a fixed order and the other of the sequences is variable in order;
• and
• multiplexing means (722, 723) for passing a cell payload from either of the asynchronous buffer and a cell payload retransmitted from the storage locations in the second sequence to the destination one of the plurality of ports;
• whereby a data sample having been transmitted in one of the payload octets of an ATM cell is retransmittable in any one of the payload octets of a full frame of octets within a time period of less than two frame periods from the moment of its storage to its port of destination.

A switching system for accommodating both asynchronous and isochronous telecommunications traffic comprising;

• means for receiving ATM cells from ports of origin and organizing the payloads of the ATM cells into frames of timeslots in a time division multiplex (TDM) transmission medium;
• means for reorganizing ATM cells from the TDM transmission medium and distributing the ATM cells to ports of destination;
• and
• a timeslot switching apparatus including;
• means for collecting frames of payloads, having datas of isochronous origins, from the time division multiplex (TDM) transmission medium,
• means for reordering the datas of a collected frame of payloads to produce reordered payloads, and
• means for substituting the reordered payloads for the corresponding payloads in the next frame of payloads in the transmission medium;
• whereby a delay introduced by the switching system into the transmission of a telephone conversation is of a duration of less than two frame periods.

An ATM switching facility comprising:

• a switching system having a plurality of ATM ports and a time switch means for providing voice band connections between telephony lines and trunks for servicing telephony terminal apparatus and interoffice telecommunications;
• at least one peripheral group unit for interfacing any of the telephony lines and trunks with one of the ATM ports and for generating and for receiving signalling and supervision information on behalf of said any of the telephone lines and trunks;
• and
• a call controller being coupled to the switching system via one of said ATM ports and being responsive to receiving signalling and supervision information via said one ATM port for transmitting timeslot switching information via said one ATM port for controlling the time switch means to set up and tear down telephone calls between any of said lines and trunks.

An ATM switching network comprising:

• a first switching system having a plurality of ATM ports and a time switch means for providing voice band connections between first telephony lines and trunks for servicing telephony terminal apparatus and interoffice telecommunications;
• at least one peripheral group unit for interfacing any of the telephony lines and trunks with one of the ATM ports of the first switching system and for generating and for receiving signalling and supervision information on behalf of said any of the first telephone lines and trunks;
• a second switching system having a plurality of ATM ports and a time switch means for providing voice band connections between second telephony lines and trunks for servicing telephony terminal apparatus and interoffice telecommunications;
• at least one peripheral group unit for interfacing any of the telephony lines and trunks with one of the ATM ports of the second switching system and for generating and for receiving signalling and supervision information on behalf of said any of the second telephone lines and trunks;
• an ATM trunk being connected between ATM ports of the respective first and second switching systems for coupling ATM cells therebetween including ATM cells with signalling and supervision information;
• and
• a call controller being coupled to one of the first and second switching systems via a respective one of said ATM ports and being responsive to receiving signalling and supervision information via said one ATM port for transmitting timeslot switching information via said one ATM port for controlling the time switch means respectively of the first and second switch means to set up and tear down telephone calls between any of said lines and trunks;
• whereby the control functions of a call controller are shared between a plurality of the switching systems in the ATM switching network without physical geographical constraint.