Method of mapping fibre channel frames based on control and type header

Abstract

A method and apparatus for processing and transferring frames of data in a computer data link that maps incoming frames to a specific buffer ring in host memory based on routing control and type fields in each frame. More particularly, a Fibre Channel link port contains receiver routing code (RRCode) registers that allow host software to set up routing control (R.sub.-- CTL) match and mask fields, and TYPE match and mask fields. The link port uses these registers to match and mask against corresponding R.sub.-- CTL/TYPE fields in a received frame to determine which of several R.sub.-- CTL/TYPE host memory buffer rings should be used to store the received frame. The link port places a code (RRCode) in a start of frame (SOF) status word associated with a frame. The RRCode indicates a specific R.sub.-- CTL/TYPE host memory buffer ring, or indicates that no match was found or that multiple matches were found. A protocol engine reads the RRCode field in the SOF status word of the received frame, and queues a direct memory access (DMA) operation to an appropriate R.sub.-- CTL/TYPE buffer ring. The host may then process the contents of the indicated buffer ring. Since the buffer rings are 'pre-sorted' as to frame type, the host may more efficiently respond to incoming frames.