Methods and systems for controlling transmission rates in networks

1. A machine implemented method, comprising:

managing, at a target, a request to transmit (R2T) queue and an associated data credit counter;

incrementing the data credit counter based on an allowed transfer rate;

selecting an R2T packet from the R2T queue;

determining if the R2T packet should be sent based on the data credit counter;

sending the R2T packet to an initiator when the R2T packet indicates data transfer less than the data credit counter; and

decrementing the data credit counter based on the R2T packet when the R2T packet is sent.

2. The method of claim 1 , wherein the allowed transfer rate is based on a minimum data rate or a maximum data rate.

3. The method of claim 2 , further comprising:

receiving a request to send an R2T packet;

adding a new R2T packet to the R2T queue when there are other R2T packets in the queue;

when there are no other R2T packets in the queue, sending the new R2T packet to an initiator when the new R2T packet indicates data transfer less than the data credit counter; and

when the new R2T packet indicates data transfer less than the data credit counter, decrementing the data credit counter based on the new R2T packet.

4. The method of claim 1 , wherein the R2T packet comprises an iSCSI R2T packet.

5. The method of claim 1 , wherein:

managing the R2T queue and the associated data credit counter are accomplished in conjunction with an iSCSI communications layer; and

sending the R2T packet to the initiator when the R2T packet indicates data transfer less than the data credit counter occurs, at least in part, with a TCP communications layer.

6. The method of claim 1 further comprising:

managing, at a second initiator, a throttle queue and an associated second data credit counter;

incrementing the second data credit counter based on an allowed transfer rate;

processing a data transmission request having an associated data transmission;

determining if the data transmission should be sent based on the second data credit counter;

sending the data transmission to a second target, when the data transmission request indicates a data transfer less than the second data credit counter; and

decrementing the second data credit counter based on the data transmission request, when the data transmission request indicates a data transfer less than the second data credit counter.

7. The method of claim 6 wherein the second initiator and the target are the same computing system.

8. A non-transitory, machine readable storage medium having stored thereon instructions for performing a method, comprising machine executable code which when executed by at least one machine, causes the machine to:

manage, at a target, a request to transmit (R2T) queue and an associated data credit counter;

increment the data credit counter based on an allowed transfer rate;

select an R2T packet from the R2T queue;

determine if the R2T packet should be sent based on the data credit counter;

send the R2T packet to an initiator when the R2T packet indicates data transfer less than the data credit counter; and

decrement the data credit counter based on the R2T packet when the R2T packet is sent.

9. The storage medium of claim 8 , wherein the allowed transfer rate is based on a minimum data rate or a maximum data rate.

10. The storage medium of claim 9 , further comprising code to:

receive a new R2T packet;

add the R2T packet to the R2T queue when there are other R2T packets in the queue;

when there are no other R2T packets in the queue, send the new R2T packet to an initiator when the new R2T packet indicates data transfer less than the data credit counter; and

when the new R2T packet indicates data transfer less than the data credit counter, decrement the data credit counter based on the new R2T packet.

11. The storage medium of claim 8 , wherein the R2T packet comprises an iSCSI R2T packet.

12. The storage medium of claim 8 , wherein the code to:

manage the R2T queue and the associated data credit counter are accomplished in conjunction with an iSCSI communications layer; and

send the R2T packet to the initiator when the R2T packet indicates data transfer less than the data credit counter occurs, at least in part, with a TCP communications layer.

13. The storage medium of claim 8 , wherein the instructions further comprise code to:

manage, at a second initiator, a throttle queue and an associated second data credit counter;

increment the second data credit counter based on an allowed transfer rate;

process a data transmission request having an associated data transmission;

determine if the data transmission should be sent based on the second data credit counter;

send the data transmission to a second target, when the data transmission request indicates a data transfer less than the second data credit counter; and

decrement the second data credit counter based on the data transmission request, when the data transmission request indicates a data transfer less than the second data credit counter.

14. The storage medium of claim 13 , wherein the second initiator and the target are the same computing system.

15. A system, comprising:

a memory containing machine readable medium comprising machine executable code having stored thereon instructions; and

a processor module coupled to the memory, the processor module configured to execute the machine executable code to:

manage, at a target, a request to transmit (R2T) queue and an associated data credit counter;

increment the data credit counter based on an allowed transfer rate;

select an R2T packet from the R2T queue;

determine if the R2T packet should be sent based on the data credit counter;

send the R2T packet to an initiator when the R2T packet indicates data transfer less than the data credit counter; and

decrement the data credit counter based on the R2T packet when the R2T packet is sent.

16. The system of claim 15 , wherein the allowed transfer rate is based on a minimum data rate or a maximum data rate.

17. The system of claim 16 , further comprising instructions to:

receive a new R2T packet;

add the R2T packet to the R2T queue when there are other R2T packets in the queue;

when there are no other R2T packets in the queue, send the new R2T packet to an initiator when the new R2T packet indicates data transfer less than the data credit counter; and

when the new R2T packet indicates data transfer less than the data credit counter, decrement the data credit counter based on the new R2T packet.

18. The system of claim 15 , wherein the R2T packet comprises an iSCSI R2T packet.

19. The system of claim 15 , wherein the code to:

manage the R2T queue and the associated data credit counter are accomplished in conjunction with an iSCSI communications layer; and

send the R2T packet to the initiator when the R2T packet indicates data transfer less than the data credit counter occurs, at least in part, with a TCP communications layer.

20. The system of claim 15 , wherein the instructions further comprise code to:

manage, at a second initiator, a throttle queue and an associated second data credit counter;

increment the second data credit counter based on an allowed transfer rate;

process a data transmission request having an associated data transmission;

determine if the data transmission should be sent based on the second data credit counter;

send the data transmission to a second target, when the data transmission request indicates a data transfer less than the second data credit counter; and

decrement the second data credit counter based on the data transmission request, when the data transmission request indicates a data transfer less than the second data credit counter.