Multicast virtual circuit switch using cell recycling

Claim 2

In a packet switch for an ATM network, said switch including a switch fabric having a plurality of inputs and a plurality of outputs, said switch fabric including means for routing a plurality of data cells from a plurality of switch fabric inputs to a plurality of switch fabric outputs, the improvement comprising means for recycling selected data cells through said switch fabric, said switch fabric including means for copying said selected data cells as they traverse the switch fabric, to thereby implement multicasting in said switch.

Claim 3

The switch of claim 1 wherein said recycling means includes means for recycling selected data cells a plurality of times through said switch fabric.

Claim 4

The switch of claim 2 wherein said copying means includes means for copying said recycled data cells to thereby create a plurality of duplicate data cells each time a data cell is recycled through said switch fabric and means for addressing said plurality of duplicate data cells for routing to different multicast destinations.

Claim 5

The switch of claim 3 wherein said copying means includes means for copying by two each of said recycled data cells to thereby create a second duplicate data cell.

Claim 6

The switch of claim 3 further comprising means for resequencing all of said data cells.

Claim 7

The switch of claim 5 wherein said resequencing means includes means for resequencing said data cells upon each pass through said switch fabric.

Claim 8

The switch of claim 5 wherein said resequencing means includes means for resequencing all of said data cells upon their last exit from said switch fabric.

Claim 9

The switch of claim 7 wherein said resequencing means includes means for resequencing all of said data cells only upon their last exit from said switch fabric.

Claim 10

The switch of claim 3 wherein said switch fabric includes said copying means, each of said recycled data cells having a plurality of output addresses, said switch fabric including means for routing said recycled data cells by comparing the addresses comprising each of said plurality of addresses.

Claim 11

The switch of claim 9 wherein said copying means includes means for copying said data cell upon comparing said addresses in a bit comparison and finding a mismatch in value of compared bits.

Claim 12

The switch of claim 9 wherein each of said recycled data cells has a pair of output addresses.

Claim 13

The switch of claim 11 wherein said copying means includes means for copying said recycled data cell upon comparing said address pairs in a bit-by-bit comparison and finding a mismatch in value of compared bits.

Claim 16

The method of claim 13 further comprising the step of resequencing all of said data cells.

Claim 17

The method of claim 14 wherein the step of resequencing includes the step of resequencing all of said data cells as they exit the switch fabric.

Claim 18

The method of claim 14 wherein the step of resequencing includes the step of resequencing said multicast data cells each time they are recycled through said switch fabric.

Claim 19

The method of claim 13 wherein each of said multicast data cells has a plurality of addresses and further comprising the step of routing said multicast data cells by comparing their addresses with each other.

Claim 20

The method of claim 17 wherein the step of copying includes the step of copying said multicast data cells upon said routing step determining a difference in said plurality of addresses.

Claim 21

The method of claim 18 wherein said addresses are expressed in a binary code, and wherein the routing step includes the step of comparing said binary codes with each other.

Claim 22

The method of claim 13 further comprising the steps of: assigning a plurality of addresses to each of said recycled data cells; and routing said data cells having a plurality of addresses by comparing said addresses with each other.

Claim 23

The method of claim 20 wherein the step of routing includes the step of comparing said plurality of addresses on a bit basis, and wherein the step of copying includes the step of copying said recycled data cell as said comparison detects a difference between corresponding bits of said plurality of addresses.

Claim 24

The method of claim 20 wherein the step of assigning addresses includes the step of assigning only two addresses to each of said recycled data cells.

Claim 25

The method of claim 22 wherein the step of routing includes the step of comparing said pair of addresses on a bit-by-bit basis, and wherein the step of copying includes the step of copying said recycled data cell as said comparison detects a difference between corresponding bits of an address pair.

Claim 26

In a packet switch for an ATM network, said switch including a switch fabric having a plurality of inputs and a plurality of outputs, said switch fabric including means for routing a plurality of data cells from a plurality of switch fabric inputs to a plurality of switch fabric outputs, and wherein at least some of said data cells have a plurality of addresses thereby indicating a multicast data cell, the improvement comprising means for recycling said multicast data cells through said switch fabric, means for routing said multicast data cells by comparing said plurality of addresses, means for copying said multicast data cells as said multicast data cells traverse said switch fabric to create at least one duplicate data cell in response to said address comparison means, means for assigning at least one address to each of said duplicate data cells, and means for resequencing all of said data cells upon their exit from said switch fabric.

Claim 27

In a packet switch for an ATM network, said switch including a switch fabric having a plurality of inputs and a plurality of outputs, said switch fabric including means for routing a plurality of data cells from a plurality of switch fabric inputs to a plurality of switch fabric outputs, and wherein at least some of said data cells have a plurality of addresses thereby indicating a multicast data cell, the improvement comprising means for recycling said multicast data cells through said switch fabric, means for routing said multicast data cells by comparing said plurality of addresses, means for copying said multicast data cells as said multicast data cells traverse said switch fabric to create at least one duplicate data cell in response to said address comparison means, means for assigning at least one address to each of said duplicate data cells, and means for resequencing all of said data cells upon their exit from said switch fabric.

Claim 28

The switch of claim 24 wherein each multicast data cell has no more than two addresses, and said copying means includes means for copying said multicast data cell only into a single duplicate data cell upon each pass through the switch fabric.