Method and apparatus for achieving fabric independent routing technique

• US 6,151,315 A
• Filed: 06/02/1997
• Issued: 11/21/2000
• Est. Priority Date: 06/02/1997
• Status: Expired due to Term

• Current Assignee: AT&T Corporation (AT&T, Inc.)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Fishman, Saul Daniel, Chen, Jiayu, Ash, Gerald Richard
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): VANDERPUYE, KENNETH N
• Application Number:
  US08/867,256
• Time in Patent Office: 1,268 Days
• Field of Search: 370/351, 370/357, 370/360, 370/230, 370/410, 370/373, 370/395, 370/522, 370/352, 370/353, 370/354, 379/221, 379/219, 379/220, 379/201, 379/202, 379/268
• US Class Current: 370/352
• CPC Class Codes: H04Q 2213/1302 Relay switches
• CPC Class Codes: H04Q 2213/1304 Coordinate switches, crossbar, 4/2 with relays, coupling field
• CPC Class Codes: H04Q 2213/13103 Memory
• CPC Class Codes: H04Q 2213/13106 Microprocessor, CPU
• CPC Class Codes: H04Q 2213/13141 Hunting for free outlet, circuit or channel
• CPC Class Codes: H04Q 2213/13164 Traffic (registration, measurement,...)
• CPC Class Codes: H04Q 2213/13166 Fault prevention
• CPC Class Codes: H04Q 2213/13204 Protocols
• CPC Class Codes: H04Q 2213/13352 Self-routing networks, real-time routing
• CPC Class Codes: H04Q 3/66 Traffic distributors

Abstract

The routing of calls in a telecommunications switching system (12₁, 12₂) comprised of one or more fabrics (22₁, 22₂, 22₃) controlled by corresponding fabric controllers (26₁,26₂ and 26₃, respectively) is carried out by a routing processor (28) independent of the fabrics. The routing processor actually selects the route for each call by specifying a channel to a neighboring switching system to carry the call. Further, the routing processor has the capability to respond to queries from other switching systems regarding trunk group status and traffic load to enable the processor to assist the routing processor of the other switching system to make routing decisions. By implementing fabric independent routing, routing processing is re-used for new fabric capacity, and is readily extended to accommodate new service types, such as bursty data services. Fabric independent routing achieves lower development cost by avoiding re-development of routing functions on new fabric controllers, as they are added, and the addition of new routing features is made on a single routing processor function versus multiple fabric controllers. Fabric independent routing allows routing processing to be implemented on processors with essentially unlimited real-time and memory resources by riding the processor technology curve, and achieves performance advantages such as reduced call set up delay and improved overall switch reliability.

Claims

1. A telecommunication network that includes at least one switching system having at least switching fabric of a particular kind for terminating at least one transmission medium and for performing call connection processes and a control mechanism for controlling the switching fabric, the improvement comprising:

a routing processor for performing call routing functions independent of the kind of fabric in said switching system, said routing processor selecting a route by communicating information to select, assign and reserve a transmission medium terminated by said switching fabric, and wherein the routing processor includes a data base for tracking routing dynamic data;

including calls in progress, traffic load bandwidth reservation, trunk group load status and trunk/busy idle status.

2. The network according to claim 1 wherein the data base stores load information accessible by a routing processor in a second switching system.

3. A telecommunication network that includes:

a plurality of switching systems, each having at least one switching fabric of a particular kind for terminating at least one transmission medium and for performing call connection process and a control mechanism for controlling the switching fabric, a signaling system for communicating information among switching systems, the improvement comprising;

a routing processor within said each switching system for performing call routing functions independent of the kind of fabric, said routing processor selecting a route by selecting, assigning and reserving a transmission medium terminated by said switching fabric, each routing processor associated with said at least one switching system having the capability to sending inquires to, and receiving inquires from a routing processor associated with another switching system, via the signaling system, regarding traffic load to enable the processor to make routing decisions.

4. The network according to claim 3 wherein each routing processor includes a data base for tracking dynamic data, including calls in progress, traffic load bandwidth reservation, trunk group load status and trunk/busy idle status.

5. The network according to claim 3 wherein the data base stores load information accessible by the routing processor said other switching system.

6. The network according to claim 3 wherein the routing functions performed by the routing processor are logical functions whereas the fabric controller performs physical routing functions.

7. The network according to claim 3 including both a circuit switch fabric and a data fabric, and wherein the routing processor performs call routing functions in each fabric.

8. The network according to claim 6 wherein the routing processor performs call routing for bursty data services within the ATM fabric in an efficient manner.

9. A method for routing calls within a telecommunication switching system, comprising the steps of:

reserving at a first telecommunications switching system having a switching fabric of a particular kind a call set-up message;

generating, in response to said call set-up message, a command to a routing processor within the telecommunications switching system to select a route for a call, said routing processor being independent of the kind of switching fabric in said switching system that terminates a communications medium that carries the call, wherein the routing processor tracks dynamic data, including calls in progress, traffic load bandwidth reservation, trunk group load status and trunk/busy idle status;

selecting a route for a call by said routing processor in response to said command to select a route; and

establishing the selected route in the switching fabric in the switching system that terminates at least one communications channel.

10. The method according to claim 9 wherein the routing processor interrogates a routing processor in a far end switching system to determine load information in order to select a route for a subsequent call.

11. The method according to claim 9 including the step of storing, at the routing processor, load information for receipt by another routing processor.

12. A telecommunication network that includes at least one switching system having at least one switching fabric of a particular kind for terminating at least one transmission medium and for performing all connection processes and a controller for controlling the switching fabric, the improvement comprising:

a routing processor for performing call routing database functions independent of the kind of fabric, said database functions including tracking calls in progress, traffic load bandwidth reservation, trunk group load status and trunk/busy idle status;

at least one call processor for performing routing functions, including selecting a route by selecting, assigning and reserving a transmission medium;

wherein the fabric controller performs trunk hunting and trunk status determination and updates the routing processor by providing the trunk status to the data base;

wherein the routing processor updates each call processor with trunk status and traffic data; and

wherein each call processor updates the routing processor with information about calls connected, calls disconnected, as well as calls blocked.

13. The network according to claim 12 wherein the call processor controls the fabric controller to specify (a) trunk group choices for routing, (b) the trunk hunt method, and (c) per-call execution of specialized call processing such as echo cancellation.