Packet network architecture for providing rapid response time

• US 4,872,159 A
• Filed: 03/31/1988
• Issued: 10/03/1989
• Est. Priority Date: 03/31/1988
• Status: Expired due to Term

• Current Assignee: American Telephone & Telegraph Company (AT&T, Inc.), Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Original Assignee: American Telephone & Telegraph Company (AT&T, Inc.)
• Inventors: Zelle, Bruce R., Hemmady, Jayant G., Roediger, Gary A., Lidinsky, William P., Weddige, Ronald C., Steele, Scott B.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Marcelo, Melvin
• Application Number:
  US07/175,546
• Time in Patent Office: 551 Days
• Field of Search: 370/60, 370/61, 370/86, 370/94, 370/56
• US Class Current: 370/352
• CPC Class Codes: H04L 2012/5651 Priority, marking, classes
• CPC Class Codes: H04L 2012/5679 Arbitration or scheduling
• CPC Class Codes: H04L 2012/5687 Security aspects
• CPC Class Codes: H04L 49/106 using space switching, e.g. crossbar or matrix
• CPC Class Codes: H04L 49/107 using shared medium
• CPC Class Codes: H04L 49/1515 Non-blocking multistage, e.g. Clos
• CPC Class Codes: H04L 49/1576 Crossbar or matrix
• CPC Class Codes: H04L 49/1584 Full Mesh, e.g. knockout
• CPC Class Codes: H04L 49/205 Quality of Service based
• CPC Class Codes: H04L 49/253 using establishment or release of connections between ports
• CPC Class Codes: H04L 49/256 Routing or path finding in ATM switching fabrics
• CPC Class Codes: H04L 49/30 Peripheral units, e.g. input or output ports
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/3081 ATM peripheral units, e.g. policing, insertion or extraction
• CPC Class Codes: H04L 49/309 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/355 Application aware switches, e.g. for HTTP
• CPC Class Codes: H04L 49/40 Constructional details, e.g. power supply, mechanical construction or backplane
• CPC Class Codes: H04L 49/506 Backpressure
• CPC Class Codes: H04L 49/555 Error detection
• CPC Class Codes: H04L 49/557 Error correction, e.g. fault recovery or fault tolerance
• CPC Class Codes: H04L 49/606 : Hybrid ATM switches, e.g. ATM&STM, ATM&Frame Relay or ATM&IP
• CPC Class Codes: H04L 63/0272 : Virtual private networks

Abstract

A high capacity metropolitan area network (MAN) is described. Data traffic from users is connected to data concentrators at the edge of the network, and is transmitted over fiber optic data links to a hub where the data is switched. The hub includes a plurality of data switching modules, each having a control means, and each connected to a distributed control space division switch. Advantageously, the data switching modules, whose inputs are connected to the concentrators, perform all checking and routing functions, while the 1024×1024 maximum size space division switch, whose outputs are connected to the concentrators, provides a large fan-out distribution network for reaching many concentrators from each data switching module. Distributed control of the space division permits several million connection and disconnection actions to be performed each second, while the pipelined and parallel operation within the control means permits each of the 256 switching modules to process at least 50,000 transactions per second. The data switching modules chain groups of incoming packets destined for a common outlet of the space division switch so that only one connection in that switch is required for transmitting each group of chained packets from a data switching module to a concentrator. MAN provides security features including a port identification supplied by the data concentrators, and a check that each packet is from an authorized source user, transmitting on a port associated with that user, to an authorized destination use that is in the same group (virtual network) as the source user. Each packet has an associated high or low priority indication. Requests for connections in the space division switch for a chained group of packets whose first packet has a high priority indication are given priority.

Claims

1. A data switching system for switching data packets from a plurality of inlets to a plurality of outlets, comprising:

a plurality of data switching means, each having at least one output, for chaining data packets from ones of said plurality of inlets to one of said plurality of outlets; and

circuit switching means connected to said plurality of data switching means for connecting outputs of said plurality of data switching means to said plurality of outlets;

each of said data switching means comprising means for requesting of said circuit switching means a connection between an output of said each data switching means and one of said plurality of outlets, said means for requesting comprising high priority and low priority queues for storing requests to set up a connection for transmitting a chain of data packets having high priority and low priority respectively.

2. The data switching system of claim 1, wherein said circuit switching means comprises at least one controller, said at least one controller comprising queues for requests from ones of said plurality of data switching modules, said queues comprising a queue for high priority requests and a queue for low priority requests.

3. The data switching system of claim 2 wherein said packets comprise data for identifying high priority packets and wherein said high priority requests comprise requests to switch a chain of packets headed by a high priority packet.

6. The data switching system of claim 1 wherein said packets comprise data for identifying high priority packets and wherein said high priority requests comprise requests to switch a chain of packets including at least one high priority packet.

7. The data switching system of claim 1 wherein each of said data packets is limited in length to a predetermined number of bits.

8. The data switching system of claim 7 wherein said high priority requests further comprise requests to switch a chain of packets including at least one high priority packet.

14. The data switching system of claim 1 wherein said packets comprise data for identifying high priority packets and wherein said high priority requests comprise requests to switch a chain of packets including a first high priority packet.

15. The data switching system of claim 7 wherein said high priority requests further comprise requests to switch a chain of packets including a first high priority packet.

4. A data switching system comprising:

a data concentration/distribution stage for concentrating data packets from a plurality of sources to one of a plurality of duplex high-speed data links and for distributing data packets from one of said plurality of duplex high-speed data links to a plurality of destinations; and

a hub for switching data packets among said plurality of high-speed data links;

wherein said hub comprises a plurality of data switching modules for switching data packets from ones of said plurality of high-speed data links to outputs of each of said data switching modules and a circuit switch for switching from said outputs of said data switching modules to ones of said plurality of high-speed data links;

wherein each of said data switching modules comprises means for chaining data packets destined for a common high-speed data link and for transmitting connection requests to said circuit switch;

wherein said circuit switch comprises at least one controller comprising queues for requests from ones of said plurality of data switching modules, said queues comprising a queue for high priority requests and a queue for low priority requests;

wherein said data packets comprise data for identifying high priority packets and wherein said high priority requests comprise requests to switch a chain of packets headed by a high priority packet;

wherein each of said data switching modules comprises a queue for high priority circuit switch setup requests and a queue for low priority circuit switch setup requests and comprises means for transmitting to said at least one controller of said circuit switch requests from said queue for high priority requests before transmitting requests from said queue for low priority requests.

9. The data switching system of claim 4 wherein said data packets are limited in size to a predetermined number of bits.

5. In a data switching system, a method of transmitting data packets each to one of a plurality of outlets, comprising the steps of:

chaining groups of data packets destined for a common outlet;

determining for each chained group of data packets whether said group is high priority or low priority;

transmitting a high priority request for a connection to a circuit switch for each chained group of data packets having high priority; and

transmitting a low priority request for a connection to said circuit switch for each chained group of data packets having low priority.

10. The method of claim 5 wherein said packets comprise data for identifying high priority packets and wherein said determining step comprises the step of determining for each data packet of a chained group of data packets whether said data packet is high priority and classifying said chained group of data packets as high priority if any of said data packets of said chained group is classified as high priority.

11. The method of claim 5 wherein said packets comprise data for identifying high priority packets and wherein said determining step comprises the step of determining for a first data packet of a chained group of data packets whether said data packet is high priority and classifying said chained group of data packets as high priority if a first of said data packets of said chained group is classified as high priority.

12. The method of claim 5 further comprising the steps of:

following said determining step, storing a high priority request for each group determined to be high priority in a high priority request queue; and

for each chained group determined to be low priority storing a low priority request in a low priority request queue.

13. The method of claim 5 further comprising the step of:

attempting to establish connections in said circuit switch in response to said high priority requests before attempting to establish connections in response to said low priority requests.

16. The method of claim 5 wherein said packets comprise data for identifying high priority packets and wherein said determining step comprises the step of determining for each data packet of a chained group of data packets whether said data packet is high priority and classifying said chained group of data packets as high priority if any of said data packets of said chained group is classified as high priority if a first data packet of said chained group is classified as high priority.