Method and system for monitoring a network link in network systems

1. A method for reporting bandwidth loss on a network link that couples a switch to a network, comprising:

determining if credit is unavailable to transmit a packet and a packet is available at a switch port for transmission;

determining bandwidth loss due to lack of credit; and

reporting the bandwidth loss to a processor of the network switch;

wherein the step of determining bandwidth loss due to lack of credit comprises:

increasing a counter value, if credit is unavailable to send a packet but a packet is available to transmit; and dividing the counter value by a timer value and multiplying a result of the division by a scaling factor to determine the bandwidth loss.

2. A method for reporting bandwidth loss on a network link that couples a switch to a network, comprising:

determining if credit is unavailable to transmit a packet and a packet is available at a switch port for transmission;

determining bandwidth loss due to lack of credit by sampling a current value of a counter, after a time interval has elapsed; dividing a counter value by a timer value; and multiplying a result of the division by a scaling factor to determine the bandwidth loss; and

reporting the bandwidth loss to a processor of the network switch.

3. The method of claim 1 , further comprising:

comparing the bandwidth loss with a threshold value; and

reporting the bandwidth loss, if the bandwidth loss is beyond the threshold value.

4. The method of claim 1 , wherein the switch is an Infiniband switch.

5. The method of claim 1 , wherein the switch is a Fibre Channel switch.

6. The method of claim 1 , wherein the switch is an Ethernet switch.

7. A method for reporting bandwidth loss on a network link that couples a switch to a network, comprising:

defining a parameter for selecting network packets to measure bandwidth loss;

determining bandwidth loss on selected network packets; and

reporting bandwidth loss to a processor for the network switch,

wherein the step of determining bandwidth loss due to variation in the bandwidth loss determination parameter further comprises:

increasing a counter if a bandwidth loss determination condition arises;

dividing a counter value by a timer value and multiplying a result of the division by a scaling factor to determine the bandwidth loss;

comparing the bandwidth loss with a threshold value; and

reporting the bandwidth loss to the processor, if the bandwidth loss is greater than the threshold value.

8. A switch element coupled to a network via a network link, comprising:

a processor for executing firmware code;

a port for receiving and transmitting network packets; and

a bandwidth loss logic that determines bandwidth loss if credit is unavailable to transmit a packet and the packet is available at the port; and reports the bandwidth loss to the processor, wherein the bandwidth loss logic, to determine the bandwidth loss, increases a counter value, if credit is unavailable to send the packet but the packet is available to transmit; divides the counter value by a timer value and multiplies a result of the division by a scaling factor.

9. A switch element coupled to a network via a network link, comprising:

a processor for executing firmware code;

a port for receiving and transmitting network packets; and

a bandwidth loss logic that determines bandwidth loss if credit is unavailable to transmit a packet and the packet is available at the port; and reports the bandwidth loss to the processor, wherein the bandwidth loss logic samples a current value of a counter, if credit is available to send a packet and a packet is available to transmit; divides a counter value by a timer value and multiplies a result of the division by a scaling factor to determine the bandwidth loss.

10. The switch element of claim 8 , wherein the bandwidth loss logic reports the bandwidth loss, if the bandwidth loss is beyond a threshold value.

11. The switch element of claim 8 , wherein the switch element is an Infiniband switch element.

12. The switch element of claim 8 , wherein the switch element is a Fibre Channel switch element.

13. The switch element of claim 8 , wherein the switch element is an Ethernet switch element.

14. A switch element coupled to a network via a network link, comprising:

a processor for executing firmware code;

a port for receiving and transmitting network packets; and

a bandwidth loss logic for determining and reporting bandwidth loss; wherein a parameter for determining bandwidth loss is defined; and the bandwidth loss logic determines bandwidth loss on network packets selected using packet selection parameters; and reports bandwidth loss to the processor, wherein the bandwidth loss logic increases a counter value if a bandwidth loss determination condition arises; divides the counter value by a timer value and multiplies a result of the division by a scaling factor to determine the bandwidth loss; compares the bandwidth loss with a threshold value; and reports the bandwidth loss to the processor, if the bandwidth loss is beyond a threshold value.

15. The switch element of claim 14 , wherein the switch element is selected from a group consisting of an Infiniband switch element, a Fibre Channel switch element and an Ethernet switch element.

16. The switch element of claim 14 , wherein the parameter or determining bandwidth loss includes a queue pair (QP) for an Infiniband switch.

17. The switch element of claim 14 , wherein the parameter for determining bandwidth loss includes a destination identifier (DLID), a Source Identifier (SLID) in an InfiniBand frame header or a combination thereof.

18. The method of claim 2 , further comprising:

comparing the bandwidth loss with a threshold value; and

reporting the bandwidth loss, if the bandwidth loss is beyond the threshold value.

19. The switch element of claim 2 , wherein the switch element is selected from a group consisting of an Infiniband switch element, a Fibre Channel switch element and an Ethernet switch element.

20. The method of claim 7 , wherein the parameter for selecting packets to measure bandwidth loss includes a queue pair (QPs) for a switch routing an InfiniBand packet.

21. The method of claim 7 , wherein the parameter for selecting packets to measure bandwidth loss includes a destination identifier (DLID), a Source identifier (SLID) or a combination thereof for a switch routing an InfiniBand packet.

22. The switch element of claim 9 , wherein the bandwidth loss logic reports the bandwidth loss, if the bandwidth loss is beyond a threshold value.

23. The switch element of claim 9 , wherein the switch element is selected from a group consisting of an Infiniband switch element, a Fibre Channel switch element and an Ethernet switch element.