| US 7,600,035 B2 | ||
| Dynamic link distance configuration for extended fabric | ||
| Nagaraj Lalsangi, Pleasanton, Calif. (US); and Balakrishma Wusirika, Pleasanton, Calif. (US) | ||
| Assigned to Brocade Communications Systems, Inc., San jose, Calif. (US) | ||
| Filed on Jan. 31, 2003, as Appl. No. 10/356,654. | ||
| Prior Publication US 2004/0153566 A1, Aug. 05, 2004 | ||
| Int. Cl. G06F 15/16 (2006.01); G06F 15/173 (2006.01) | ||
| U.S. Cl. 709—234 [709/224; 370/234; 370/235; 370/236; 370/239] | 27 Claims |
| 1. A method to dynamically allocate credits to a port in a Fibre Channel network, the method comprising:
connecting a first port on a first device to a second port on a second device to form a link;
the first port sending a unique signal to a second port and starting a timer;
the first port receiving the unique signal returned from the second port and stopping the timer; and
allocating credits according to the time elapsed on the timer,
wherein allocating credits according to the time elapsed on the timer includes:
calculating the distance according to the time elapsed on the timer; and
allocating credits corresponding to the distance between the first and second ports, and
wherein calculating the distance according to the time elapsed on the timer uses the following formula:
distance=(LRT_LATENCY*3)/(20*RI) Eq.(1)
where distance is the link distance in km;
LRT_LATENCY is the time lapse between timer stops and starts, in microseconds and
RI is the refractive index of glass (worst case) in the fiber optic connecting the two ports.
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