the fc 3 layer layer 340 may include hardware and or software to control advanced features such a multicasting etc layer 350 may be referred to as the mapping layer or fc 4 layer layer 350 is a software based layer that defines application interfaces that may execute over fibre channel and mapping rules between upper layer applications and the lower fibre channel layers commonly supported application protocols include fiber distributed data interface fddi small computer system interface scsi high performance parallel interface hippi and intelligent peripheral interface ipi in one embodiment described further below a scsi application protocol is mapped to the lower fibre channel layers such that a modified set of scsi over fibre channel commands may be used for exchanging data between scsi defined devices modifications may be made only to command frames so that the conventional scsi over fibre channel data packet heirarchy such as data frames sequences consisting of one or more related unidirectionally transmitted data frames and exchanges consisting of one or more sequences may be maintained fig4 illustrates one embodiment of a system 400 having a set of pipes 421 428 that may operate concurrently on a single fibre channel link shown are clients 210 and 220 coupled to pipes within link 420 which are in turn coupled to target devices within media server 230 client 210 includes shared memory buffers 411 413 which may store data that is ready for transmission via a fibre channel link or that is received from a fibre channel link client 220 includes shared memory buffers 414 416 which may also store data that is ready for transmission via a fibre channel link or that is received from a fibre channel link media server.