Network switch with dynamic backpressure per port

Claim 2

A network switch, comprising: a plurality of network ports that send and receive data packets, each of said plurality of network ports including core logic that receives a backpressure indication and that transmits a jamming sequence to terminate data packet transmission; a memory that temporarily stores data packets received from any of said plurality of network ports; and a switch manager coupled to said memory and said plurality of network ports that determines at least one threshold condition of said memory, that determines if a new data packet being received by one of said plurality of network ports is to be stored in said memory for transmission by another of said plurality of network ports, and if so, that provides said backpressure indication to said one of said plurality of network ports to terminate said new data packet if said at least one threshold condition would be violated by storage of said new data packet.

Claim 3

The network switch of claim 1 for enabling communication among a plurality of network devices coupled through network segments, wherein each of said plurality of network ports further comprises: a network interface that receives and transmits data packets on a corresponding network segment and that provides said jamming sequence onto said corresponding network segment in response to a collision command; and a data interface coupled to said switch manager and said network interface that sends and receives data and that detects said backpressure indication and provides said collision command.

Claim 4

The network switch of claim 1 , further comprising: a data bus coupled to said plurality of network ports and to said switch manager; and said switch manager executing a backpressure cycle on said data bus to provide said backpressure indication.

Claim 5

The network switch of claim 1 for receiving and transmitting data packets, each data packet including a source address and a destination address, further comprising: said memory further storing each source address received and a corresponding port number identifying one of said plurality of network ports; and said switch manager including control logic that provides said backpressure indication to said one of said plurality of network ports receiving said new data packet if the destination address of said new data packet is not found in said memory, and that provides said backpressure indication if the destination address is found in said memory and a port number corresponding to the destination address does not identify said one of said plurality of network ports.

Claim 6

The network switch of claim 4 , wherein said control logic provides said backpressure indication if the destination address indicates a broadcast packet.

Claim 7

The network switch of claim 4 , wherein said switch manager further comprises: polling logic coupled to said control logic that periodically determines whether each of said plurality of network ports is available for transmitting data packets; and said control logic determining if said one of said plurality of network ports receiving said new data packet and said destination network port support cut-through mode, and not providing said backpressure indication if said destination network port is available for receiving and transmitting said new data packet.

Claim 8

The network switch of claim 1 , wherein said memory is divided into a plurality of sectors, and wherein said at least one threshold condition includes a maximum number of data packet sectors storing data packets received by a network port.

Claim 9

The network switch of claim 1 , wherein said at least one threshold condition includes a maximum number of data packets stored in said memory to be transmitted by a network port.

Claim 10

The network switch of claim 1 , wherein said at least one threshold condition includes a minimum number of free sectors available in said memory for storage of data packets.

Claim 11

The network switch of claim 1 , wherein said at least one threshold condition includes a maximum number of broadcast data packets stored in said memory.

Claim 12

A network system, comprising: a plurality of networks, each including at least one data network device coupled through a network segment that sends and receives data packets; and a network switch coupled to said plurality of networks that transfers data packets, said network switch comprising: a plurality of network ports, each including: a network interface that receives and transmits data packets on a corresponding network segment and that provides a jamming sequence onto said corresponding network segment in response to a collision command; and a data bus interface coupled to said network interface that sends and receives data and that detects a backpressure cycle and provides said collision command; a data bus coupled to said data bus interface of each of said plurality of network ports; a memory that temporarily stores data packets received by any of said plurality of network ports and that stores addresses of network devices and associated network port numbers; and a switch manager coupled to said data bus and said memory, comprising: a buffer that receives and stores a packet header of a new data packet received by one of said plurality of network ports, said packet header including a source address and a destination address; control logic coupled to said data bus and said buffer that transfers said packet header to said buffer and that asserts a hash request signal, that detects packet status signals and a backpressure signal and that executes said backpressure cycle on said data bus to said one of said plurality of network ports receiving said new packet if said backpressure signal is provided and if said packet status signals indicate that said new data packet must otherwise be sent to said memory; and hash logic coupled to said buffer, said control logic and said memory that detects said hash request signal and that respondingly determines whether said new data packet would violate at least one threshold condition of said memory if transferred to said memory and asserts said backpressure signal indicative thereof, and that determines whether said new data packet is to be dropped, forwarded, or broadcasted and asserts said packet status signals indicative thereof.

Claim 13

A network system, comprising: a plurality of networks, each including at least one data network device coupled through a network segment that sends and receives data packets; and a network switch coupled to said plurality of networks that transfers data packets, said network switch comprising: a plurality of network ports, each including: a network interface that receives and transmits data packets on a corresponding network segment and that provides a jamming sequence onto said corresponding network segment in response to a collision command; and a data bus interface coupled to said network interface that sends and receives data and that detects a backpressure cycle and provides said collision command; a data bus coupled to said data bus interface of each of said plurality of network ports; a memory that temporarily stores data packets received by any of said plurality of network ports and that stores addresses of network devices and associated network port numbers; and a switch manager coupled to said data bus and said memory, comprising: a buffer that receives and stores a packet header of a new data packet received by one of said plurality of network ports, said packet header including a source address and a destination address; control logic coupled to said data bus and said buffer that transfers said packet header to said buffer and that asserts a hash request signal, that detects packet status signals and a backpressure signal and that executes said backpressure cycle on said data bus to said one of said plurality of network ports receiving said new packet if said backpressure signal is provided and if said packet status signals indicate that said new data packet must otherwise be sent to said memory; and hash logic coupled to said buffer, said control logic and said memory that detects said hash request signal and that respondingly determines whether said new data packet would violate at least one threshold condition of said memory if transferred to said memory and asserts said backpressure signal indicative thereof, and that determines whether said new data packet is to be dropped, forwarded, or broadcasted and asserts said packet status signals indicative thereof.

Claim 14

The network system of claim 11 , wherein said control logic further comprises: data bus control logic coupled to said buffer and said data bus to execute cycles on said data bus; and arbitration logic coupled to said data bus control logic and said hash logic to determine cycles to be executed by said data bus control logic.

Claim 15

The system switch of claim 12 , wherein said arbitration logic further comprises: polling logic coupled to said data bus control logic and said data bus that periodically determines whether each of said plurality of network ports is available for transmitting data packets.

Claim 16

The network system of claim 11 , further comprising: said memory storing said at least one threshold condition; and said hash logic further comprising: a memory controller coupled to said memory that retrieves at least one threshold value indicative of said at least one threshold condition; and a hash controller coupled to said buffer, said memory controller and said control logic that receives said hash request, requests threshold conditions from said memory controller and that asserts said backpressure and packet status signals.

Claim 17

The network system of claim 11 , wherein said at least one threshold condition includes a maximum number of memory sectors storing data packets received by a network port.

Claim 18

The network system of claim 11 , wherein said at least one threshold condition includes a maximum number of data packets stored in said memory to be transmitted by a network port.

Claim 19

The network system of claim 11 , wherein said at least one threshold condition includes a minimum number of free sectors available in said memory for storage of data packets.

Claim 20

The network system of claim 11 , wherein said at least one threshold condition includes a maximum number of broadcast data packets stored in said memory.

Claim 21

A network switch, comprising: a plurality of network ports that send and receive data packets, each of said plurality of network ports including core logic that receives a backpressure indication and that transmits a jamming sequence to terminate data packet transmission; a memory that temporarily stores data packets received from any of said plurality of network ports; and a switch manager coupled to said memory and said plurality of network ports that determines at least one threshold condition of said memory and that provides said backpressure indication to said one of said plurality of network ports to terminate said new data packet if said at least one threshold condition would be violated by storage of said new data packet.

Claim 22

A network switch, comprising: a plurality of network ports that send and receive data packets, each of said plurality of network ports including core logic that receives a backpressure indication and that transmits a jamming sequence to terminate data packet transmission; a memory that temporarily stores data packets received from any of said plurality of network ports; and a switch manager coupled to said memory and said plurality of network ports that determines at least one threshold condition of said memory and that provides said backpressure indication to said one of said plurality of network ports to terminate said new data packet if said at least one threshold condition would be violated by storage of said new data packet.

Claim 27

The method of claim 21 wherein said receiving the packet header comprises: receiving a destination address from the packet header; and determining if the destination address is a unicast address.

Claim 28

The method of claim 22 , the destination address being unicast, wherein said determining if the data packet is to be stored in the network switch further comprises: determining if the destination address is known; if the destination address is known, retrieving a destination port number; and comparing a source port number and the destination port number.

Claim 29

The method of claim 23 , the destination address being known and the source and destination ports being different, wherein said examining the packet header in light of existing data packets that are stored in the network switch to determine if the network switch would violate the threshold condition by storing the data packet in the network switch comprises: comparing the number of memory sectors storing data packets received by the source port with a maximum number of receive sectors for the source port; and comparing the number of data packets stored in the network switch for transmission by the destination port with a maximum number of transmit packets for the destination port.

Claim 30

The method of claim 23 , the destination address being known and the source and destination ports being different, further comprising: determining if the source and destination ports both support and are compatible with cut-through mode of operation; and determining if the destination port is available for transmission of the data packet.

Claim 31

The method of claim 23 , the destination address being unknown, wherein said examining the packet header in light of existing data packets that are stored in the network switch to determine if the network switch would violate the threshold condition by storing the data packet in the network switch further comprises: comparing the number of memory sectors storing data packets received by the source port with a maximum number of receive sectors for the source port; comparing the number of data packets stored in the network switch for transmission by each destination port of the data packet with corresponding maximum numbers of transmit packets; and comparing the number of broadcast packets currently stored in the network switch with a maximum number of broadcast packets.

Claim 32

The method of claim 22 , the destination address not being unicast, wherein said step of examining the packet header in light of existing data packets that are stored in the network switch to determine if the network switch would violate the threshold condition by storing the data packet in the network switch further comprises: comparing the number of memory sectors storing data packets received by the source port with a maximum number of receive sectors for the source port; comparing the number of data packets stored in the network switch for transmission by each destination port of the data packet with corresponding maximum numbers of transmit packets; and comparing the number of broadcast packets currently stored in the network switch with a maximum number of broadcast packets.