Multiple-local area networks interconnected by a switch

• US 6,353,858 B1
• Filed: 11/30/1998
• Issued: 03/05/2002
• Est. Priority Date: 11/30/1998
• Status: Expired due to Term

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Vasquez, Silverio C., Raamot, Jaan
• Primary Examiner(s): Maung, Zarni
• Assistant Examiner(s): LIN, WEN TAI
• Application Number:
  US09/203,016
• Time in Patent Office: 1,191 Days
• Field of Search: 709/200, 709/218, 709/249, 709/310, 709/311, 370/388, 370/395, 370/397, 370/401, 370/351, 370/389, 370/400, 340/825.79, 713/150, 713/151
• US Class Current: 709/249
• CPC Class Codes: H04L 12/4625 Single bridge functionality, e.g. connection of two networks over a single bridge
• CPC Class Codes: H04L 49/101 using crossbar or matrix
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches

Abstract

Local area networks are dynamically connected to one another by a switching system only when there is a packet to be exchanged between the two local area networks, otherwise the local area networks operate as separate and independent local area networks. The switching system can concurrently interconnect multi-pairs of local area networks together. The overall capacity of the local area networks interconnected via the switching system is increased since the local area networks operate free of other local area networks except when directly exchanging packets with another local area network. The switching system comprises a space switching unit and switch interface units with each switch interface unit interconnecting an individual local area network to the space switching unit. When a first switch interface unit receives a packet from a connected local area network destined for another local area network, the first switch interface unit establishes a first unilateral path to the other local area network and determines if the other local area network is idle. If the other local area network is idle, the first switch interface unit establishes a second unilateral path from the connected local area network to the other local area network via the space switching unit so that the packet from the connected local area network can be transmitted to the other local area network.

Claims

1. An apparatus for interconnecting a plurality of packet networks for transmission of packets between ones of the plurality of packet networks, comprising:

a switching unit connected to each of the plurality of packet networks via an individual interface to each of the networks;

a decoder in an interface unit responsive to a packet from a connected one of the plurality of packet networks for determining if the packet is destined for another one of the plurality of packet networks;

a controller in the interface unit responsive to the determination that the packet is destined for the other one of the plurality of packet networks for determining if the other one of the plurality of packet networks is idle by establishing a first unilateral path through the switching unit from the other one of the plurality of packet networks to the connected one of the plurality of packet networks; and

the controller further establishing a second unilateral path through the switching unit from the connected one of the plurality of packet networks to the other one of the plurality of packet networks upon the other one of the plurality of packet networks being idle, said apparatus allowing only immediate transmission of said packets based on the other of the packet networks being idle.

2. The apparatus of claim 1 wherein the controller further removing the first and second unilateral paths in response to the end of transmission of the packet.

3. The apparatus of claim 2 wherein the decoder comprises a memory for buffering only a portion of the packet, said portion including address information;

and

an address circuit for decoding an address of the packet to determine destination.

4. The apparatus of claim 2 wherein the plurality of packet networks is a plurality of local area networks.

5. The apparatus of claim 4 further comprises a device for generating a collision message to the connected one of the plurality of local area networks in responsive to the other one of the plurality of local area networks being determined to be busy by the controller.

6. The apparatus of claim 5 wherein the switching unit is a non-blocking switch and the connected one of the plurality of local area networks can transmit the packet to all of the plurality of local area networks via the switching unit.

7. The apparatus of claim 3 wherein the switching unit is a space switching unit.

8. A method for communicating packets between a plurality of packet networks interconnected by a switching unit via an individual interface unit to each of the plurality of packet networks, comprising the steps of:

determining if a packet from a first one of the plurality of packet networks is destined for a second one of the plurality of packet networks;

establishing a first unilateral path through the switching unit from the second one of the plurality of packet networks to the first one of the plurality of packet networks;

determining if the second one of the plurality of packet networks is idle via the first unilateral path; and

establishing a second unilateral path through the switching unit from the first one of the plurality of packet networks to the second one of the plurality of packet networks upon the second one of the plurality of packet networks being idle, wherein only immediate transmission of said packets based on the other of the packet networks being idle is allowed.

9. The method of claim 8 further comprises the step of removing the first and second unilateral paths in response to the end of transmission of the packet.

10. The method of claim 9 wherein the plurality of packet networks is a plurality of local area networks.

11. The method of claim 10 further comprises the step of generating a collision message to the first one of the plurality of local area networks in response to the second one of the plurality of local area networks being determined to be busy.

12. The method of claim 11 wherein the switching unit is a non-blocking switch and first one of the plurality of local area networks can transmit the packet to all of the plurality of local area networks via the switching unit.

13. The method of claim 11 wherein the switching unit is a space switching unit.

14. An apparatus for interconnecting a plurality of packet networks for transmission of packets between ones of the plurality of packet networks, comprising:

a switching unit connected to each of the plurality of packet networks via an individual interface to each of the networks;

a decoder in an interface unit responsive to a packet from a connected one of the plurality of packet networks for determining if the packet is destined for another one of the plurality of packet networks;

a controller in the interface unit responsive to the determination that the packet is destined for the other one of the plurality of packet networks for determining if the other one of the plurality of packet networks is idle by establishing a first unilateral path through the switching unit from the other one of the plurality of packet networks to the connected one of the plurality of packet networks; and

the controller further establishing a second unilateral path through the switching unit from the connected one of the plurality of packet networks to the other one of the plurality of packet networks upon the other one of the plurality of packet networks being idle, said apparatus accepting packets for transmission only if the other of the packet networks is idle.