Telecommunication systems
A telecommunications system having a format converter provides bi-directional communications between TDM signals on one side and ATM signals on the other. An ATM aggregate receives and transmits ATM signals, and a TDM interface receives and transmits TDM signals. The format converter has an ATM bus and a TDM bus connected to their respective interfaces, and service-specific adapters are connected between the ATM bus and the TDM bus.
1. A format converting device for performing bi-directional conversion within a telecommunication system comprising:
a time division multiplexing (TDM) bus connected to a TDM interface and configured to receive and transmit data streams;
a packet bus connected to a packet communications interface and configured to receive and transmit data packet streams;
a separate segmentation and reassembly circuit; and
a service-specific adaptation unit connected between the TDM bus and the packet bus, the service-specific adaptation unit including a cell processor connected to an adaptation circuit and a control processor, the cell processor having a routing function that routes system control signal cells to the control processor through a segmentation and reassembly interface connected to the separate segmentation and reassembly circuit.
2. The format converting device as claimed in claim 1 , wherein the packet bus is connected to a system controller within the telecommunication system.
3. The format converting device as claimed in claim 2 , wherein the system controller is configured to transmit and receive system control signals via the packet bus to the format converting device.
4. The format converting device as claimed in claim 1 , wherein the cell processor strips additional headers from control signals as the control signals are routed to the segmentation and reassembly circuit.
5. The format converting device as claimed in claim 4 , wherein the control signals are cells, said device being configured to add an additional header to each control signal cell to direct routing of the control signal cells within the telecommunication system.
6. The format converting device as claimed in claim 5 , wherein the bi-directional conversion performed by the format converting device is specific to voice.
7. The format converting device as claimed in claim 5 , wherein the bi-directional conversion performed by the format converting device is specific to frame relay.
8. The format converting device as claimed in claim 5 , wherein the bi-directional conversion performed by the format converting device is specific to circuit emulation.
9. The format converting device as claimed in claim 5 , wherein the bi-directional conversion performed by the format converting device is specific to native asynchronous transfer mode (ATM).
10. The format converting device as claimed in claim 5 , wherein the cell processor is configured to maintain a plurality of output queues for routing of the control signal cells to the TDM bus, the queues being maintained on a priority scheme according to headers that include a virtual path identifier (VPI) and a virtual channel identifier (VCI).
11. The format converting device as claimed in claim 5 , wherein the cell processor includes a mapping function for adding the additional headers to the control signal cells, respectively.
12. The format converting device as claimed in claim 1 , wherein the cell processor includes a dedicated application-specific integrated circuit (ASIC).
13. A format converting device for performing bi-directional conversion between a time division multiplexing (TDM) interface and a packet communication interface within a telecommunication system comprising:
a TDM bus connected to the TDM interface;
a packet bus connected to the packet communication interface;
a service-specific adaptation unit connected to and between each of the TDM bus and the packet bus, the service-specific adaptation unit configured to extract at least one TDM signal received from the TDM interface via the TDM bus and to convert the at least one TDM signal to a data packet signal and output the converted data packet signal to the packet bus for routing to the packet communication interface;
the service-specific adaptation unit further configured to extract at least one data packet signal received from the packet communication interface via the packet bus, convert the at least one data packet signal to a TDM signal and output the converted TDM signal to the TDM bus for routing to the TDM interface;
the service-specific adaptation unit including a control processor and a cell processor;
the cell processor being coupled to the packet bus through a packet bus interface and being coupled to the TDM bus through an adaptation circuit and TDM bus interface; and
the cell processor including a segmentation and reassembly interface connected to a separate segmentation and reassembly circuit, the cell processor being configured to route control signal cells to the control processor through the segmentation and reassembly interface.
14. The format converting device as claimed in claim 13 , wherein the cell processor is configured to maintain a plurality of output queues for routing of the control signal cells to the TDM bus, the queues being maintained on a priority scheme according to headers that include a virtual path identifier (VPI) and a virtual channel identifier (VCI).
15. The format converting device as claimed in claim 13 , wherein the service-specific adaptation unit includes a system control processor for transmitting and receiving control signal cells.
16. The format converting device as claimed in claim 13 , wherein the cell processor includes a mapping function for adding additional headers to the control signal cells.
17. A format converting method comprising:
receiving and transmitting time division multiplexing (TDM) data streams over a TDM bus of a format converter, the TOM bus being connected to system TDM interface;
receiving and transmitting data packet streams that include IP packets over a packet bus of the format converter, the packet bus being connected to a system packet communication interface;
performing bi-directional conversion using the format converter, the format converter including a service-specific adaptation module connected between the TDM bus and the packet bus;
extracting, by the service-specific adaptation module, at least one TDM signal received from the TDM interface via the TOM bus, converting the at least one TDM signal to a data packet signal, and outputting the converted data packet signal to the packet bus for routing to the packet communication interface;
further extracting, by the service-specific adaptation module, at least one data packet signal received from the packet communication interface via the packet bus, converting the at least one data packet signal to a TOM signal, and outputting the converted TDM signal to the TDM bus for routing to the TDM interface; and
transmitting and receiving control signals via the packet bus to the format converter, and transmitting and receiving control signals over the TDM bus via a separate dedicated TDM control signal link.
18. The method as claimed in claim 17 , further comprising the format converter maintaining a plurality of output queues for routing of cells to the TDM bus, the queues being maintained on a priority scheme according to headers that include a virtual path identifier (VPI) and a virtual channel identifier (VCI).
19. The method as claimed in claim 17 , wherein the format converter includes a control processor and a cell processor including a segmentation and reassembly interface connected to a separate segmentation and reassembly circuit, the method further including the step of the cell processor routing control signal cells to the control processor through the segmentation and reassembly interface.