Patent ID: 7391723

Claim:
A fibre channel interface to a fibre channel communications line comprising: a) an external interface connected to the communications line so as to receive and transmit fibre channel frames having headers and data payloads over the communications line; b) a fibre channel controller converting frames received from the external interface into data and for converting data into frames to be transmitted by the external interface; and c) a CRC module connected between the external interface and the fibre channel controller, the CRC module connected so as to monitor data flowing from the external interface to the fibre channel controller and connected so as to have data flowing from the fibre channel controller to the external interface pass through the CRC module; the CRC module having i) a first CRC generator that generates a CRC value based on a starting value and data to be analyzed, ii) a first frame header processor with circuitry to analyze headers and transmit data payloads to the CRC generator as data to be analyzed, iii) a first memory in communication with the first CRC generator, and iv) a frame-level CRC component having a buffer, the data flowing from the fibre channel controller being stored temporarily in the buffer before being passed to the external interface; d) wherein the fibre channel interface operates in a first mode by generating a sequence-level CRC across multiple frames by storing intermediate CRC values for a sequence in the first memory for later use by the first CRC generator as the starting value when analyzing a next frame in the sequence; and e) wherein the fibre channel interface operates in a second mode wherein a newly generated frame level CRC value generated by the fibre channel controller is replaced in the buffer of the frame-level CRC component by an previous frame level CRC value.