Distributed memory switching hub

• US 6,175,571 B1
• Filed: 12/09/1997
• Issued: 01/16/2001
• Est. Priority Date: 07/22/1994
• Status: Expired due to Term

• Current Assignee: Network Peripherals, Inc. (Hale Capital Management LP)
• Original Assignee: Network Peripherals, Inc. (Hale Capital Management LP)
• Inventors: Harwood, Michael J., Schneider, Herb O., Scherbarth, Darrell R., Haddock, Stephen R.
• Primary Examiner(s): TON, DANG T
• Application Number:
  US08/987,331
• Time in Patent Office: 1,134 Days
• Field of Search: 370/401, 370/400, 370/402, 370/403, 370/404, 370/405, 370/406, 370/408, 370/423, 370/424, 370/445, 370/447, 370/461, 370/462, 370/440, 370/439, 370/254, 370/255, 370/258, 370/455, 370/465, 370/466, 370/451, 370/428, 370/429, 370/412, 370/407, 370/473, 370/474, 370/476, 370/425, 370/381, 370/374, 370/352
• US Class Current: 370/423
• CPC Class Codes: H04L 12/5601 Transfer mode dependent, e.g. ATM
• CPC Class Codes: H04L 49/201 Multicast operation; Broadcast operation
• CPC Class Codes: H04L 49/3009 Header conversion, routing tables or routing tags
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches

Abstract

A distributed memory switching hub interconnecting heterogeneous local area networks operating at different transmission speeds for receiving, storing and forwarding frames of data. The distributed memory switching hub employs a distributed memory architecture in which memory storage for frames of data received and to be transmitted is located at each low speed LAN port of the distributed memory switching hub. A distributed memory architecture renders unnecessary the need for a central programmable processor or shared common memory to store and forward frames received by the distributed memory switching hub.

Claims

1. An apparatus for exchanging data between a first data network and a plurality of second data networks, said apparatus comprising:

a data bus internal to said apparatus;

a first port that couples said first data network to said data bus to transfer said data between said first data network and said data bus, said first port having no dedicated memory to store said data to be transferred between said first data network and said data bus; and

a plurality of bidirectional second ports, each coupled to one of said plurality of second data networks and to said data bus to transfer said data between said one of said plurality of second data networks and said data bus, and each having its own dedicated memory to store said data to be transferred between said one of said plurality of second data networks and said data bus.

2. An apparatus for exchanging data between a first local area network, (LAN) and a plurality of second local area networks (LANs), said apparatus comprising:

a data bus internal to said apparatus;

a first LAN port that couples said first LAN to said data bus to transfer said data between said first LAN and said data bus, said first LAN port having no discrete memory to store said data to be transferred between said first LAN and said data bus; and

a plurality of bidirectional second LAN ports, each coupled to one of said plurality of second LANs and to said data bus to transfer said data between said one of said plurality of second LANs and said data bus, and each incorporating its own discrete memory to store said data to be transferred between said one of said plurality of second LANs and said data bus.

3. The apparatus of claim 2, wherein said data comprises encapsulated data.

4. An apparatus for exchanging data between a first local area network (LAN) and a second local area networks (LANs), said apparatus comprising:

an internal data bus;

a first LAN port that couples said first LAN to said internal data bus to transfer said data between said first LAN and said internal data bus, said first LAN port having no dedicated memory to store said data to be transferred between said first LAN and said internal data bus; and

a second bidirectional LAN port coupled to said second LAN and to said internal data bus to transfer said data between said second LAN and said internal data bus, and having its own memory to store said data to be transferred between said second LAN and said internal data bus.

5. An apparatus for exchanging data between a high speed local area network (LAN) and a plurality of low speed local area networks (LANs), said apparatus comprising:

a high speed internal data bus;

a high speed LAN port that couples said high speed LAN to said high speed internal data bus to transfer said data between said high speed LAN and said high speed internal data bus, said high speed LAN port having no dedicated memory to store said data to be transferred between said high speed LAN and said high speed internal data bus; and

a plurality of bidirectional low speed LAN ports, each coupled to one of said plurality of low speed LANs and to said high speed internal data bus to transfer said data between said one of said plurality of low speed LANs and said high speed internal data bus, and each having its own memory to store said data to be transferred between said one of said plurality of low speed LANs and said high speed internal data bus.

6. The apparatus of claim 5, wherein said high speed internal data bus operates at a data transmission speed equal to said high speed LAN.

7. An apparatus for exchanging data between a high speed local area network (LAN) and a low speed local area network (LAN), said apparatus comprising:

a high speed internal data bus that operates at a data transmission speed equal to said high speed LAN;

a high speed LAN port that couples said high speed LAN to said high speed internal data bus to transfer said data between said high speed LAN and said high speed internal data bus, said high speed LAN port having no dedicated memory to store said data to be transferred between said high speed LAN and said high speed internal data bus; and

a low speed bidirectional LAN port coupled to said low speed LAN and to said high speed internal data bus to transfer said data between said low speed LAN and said high speed internal data bus, and having its own memory to receive and store data to be transferred between said low speed LAN and said high speed internal data bus.

8. An apparatus that interconnects a first local area network (LAN) operating at a first data transmission speed, and a plurality of second local area networks (LANs) operating at a second data transmission speed to communicate data among said first LAN and said plurality of second LANs, said apparatus comprising:

a data bus that operates at said first data transmission speed;

a first port that couples said first LAN to said data bus to transfer said data between said first LAN and said data bus, said first port having no dedicated memory to store said data to be transferred between said first LAN and said data bus;

a plurality of second ports, each coupled to one of said plurality of second LANs and to said data bus to transfer said data between one of said plurality of second LANs and said data bus; and

a memory architecture, wherein memory is physically distributed among said second bidirectional ports to receive, store and forward said data between said data bus and said plurality of second LANs.

9. A switching hub that interconnects heterogeneous local area networks to transmit data therebetween, comprising:

a fiber distributed data interface (FDDI) port that couples a FDDI ring to said switching hub;

a plurality of local area network (LAN) ports each coupled to a carrier sense, multiple access bus with collision detection (CSMA/CD bus);

an internal data bus that couples said FDDI port and said plurality of LAN ports to transfer data among said FDDI port and said plurality of LAN ports, said FDDI port having no dedicated memory to store said data transferred among said FDDI port and said plurality of LAN ports; and

a memory of architecture, wherein memory is physically distributed among each of said plurality of bidirectional LAN ports, each of said plurality of bidirectional LAN ports operating autonomously to receive, store and forward said data between said internal data bus and said CSMA/CD bus.

10. The switching hub of claim 9, wherein said data comprises encapsulated data.

11. The switching hub of claim 9, wherein said FDDI ring operates at a data transmission speed of 100 megabits per second.

12. The switching hub of claim 9, wherein said CSMA/CD bus operates at a data transmission speed of 10 megabits per second.

13. The switching hub of claim 9, wherein said internal data bus is capable of operating at a data transmission speed of 100 megabits per second.

14. In a switching hub that interconnects a fiber distributed data interface (FDDI) ring operating at a data transmission speed of 100 megabits per second and a plurality of carrier sense, multiple access buses with collision detection (CSMA/CD buses) operating at a data transmission speed of 10 megabits per second to transmit data therebetween, an improvement comprising:

an internal data bus that operates at said data transmission speed of 100 megabits per second;

a FDDI port that couples said FDDI ring to said internal data bus, said FDDI port having no dedicated memory to store data to be transmitted between said FDDI ring and said internal data bus; and

a plurality of bidirectional local area network (LAN) ports, each coupled to one of said CSMA/CD buses and to said internal data bus to transfer said data between said one of said CSMA/CD buses and said internal data bus, and each having its own memory to receive and store said data to be transferred between one of said CSMA/CD buses and said internal data bus.