Fibre Channel Data Communication Service (FCDCS) is proposed in this paper that implements an optimized peer-to-peer communication mechanism based on SCSI target mid-level subsystem. FCDCS uses the standard FCP protocol mapping and vendorspecific commands, and the command descriptor blocks (CDBs) defined in this paper. It maintains full compatibility with the Fibre Channel standard. FCDCS can operate with QLA2342 (2Gb/sec) Fibre Channel Host Bus Adapters (HBA) from Qlogic corporation, and can operate in arbitrated loop (FC_AL), switched fabric, or point-to-point topology. With FCDCS, CPU's loads have been reduced as data transfers directly to and form user buffers by bypassing host memory. Data throughput has been increased greatly by transferring data in larger package. Off-the-shelf 2Gb/sec FC host bus adapters are used in the experiments.