Abstract: A storage area network (“SAN”) and a system is provided. The SAN includes, a host bus adapter operationally coupled with a credit extender, wherein the credit extender receives frames from a Fibre Channel network and sends the received frames to the HBA based on buffer space available in the HBA. The HBA notifies other Fibre Channel ports of buffer space available in the credit extender. The HBA sends a signal to the credit extender notifying the credit extender of available buffer space in the HBA. The HBA includes a management port for interfacing the HBA with the credit extender.

Abstract: A router for use in a network includes a scalable architecture and performs methods for implementing quality of service on a logical unit behind a network port; and for implementing storage virtualization. The architecture includes a managing processor, a supervising processor; and a plurality of routing processors coupled to a fabric. The managing processor has an in-band link to a routing processor. A routing processor receives a frame from the network, determines by parsing the frame, the protocol and logical unit number, and routes the frame to a queue according to a traffic class associated with the logical unit number in routing information prepared for the processors. An arbitration scheme empties the queue in accordance with a deficit round robin technique. If a routing processor detects the frame's destination is a virtual entity, and so is part of a virtual transaction, the router conducts a nonvirtual transaction in concert with the virtual transaction.