Patent ID: 8203950

Claim:
A method for providing quality of service in a storage area network, the storage area network having one or more hosts and one or more targets, the method comprising: receiving, at a switch, quality of service information regarding one or more flows from a user, the quality of service information including one or more bandwidth parameters pertaining to a flow, wherein the bandwidth parameters include a quality of service guarantee for a level of granularity, the level of granularity indicating whether the flow for which the quality of service is guaranteed concerns a specific host, a specific target, a specific target LUN, or a combination of two or more of such specific host, target, or target LUN; receiving a frame at the switch; calculating, at the switch, available bandwidth for flows not associated with the received quality of service information; determining an expected data burst associated with the frame; comparing the expected data burst with a current available bandwidth for the flow associated with the frame, or, if the frame is not associated with a flow, comparing the expected data burst with a current available bandwidth for flows not associated with the quality of service information; and limiting, at the switch, the rates of transmissions of frames in the storage area network based at least in part on using the received quality of service information to determine when to forward the frame to its destination, wherein calculating available bandwidth for flows not associated with the received quality of service information comprises using values for the total available bandwidth and bandwidth parameters from the quality of service information.