Apparatus and methods for determining latency of a network port

摘要

One embodiment relates to a method for determining a latency of a network port. Read and write pointers for a FIFO are sampled at the same time. An average difference between a plurality of samples of the read and write pointers is determined. Another embodiment relates to an apparatus for providing timestamps to packets at a network port. Registers sample read and write pointers of a FIFO using a sampling clock. Logic circuitry determines an average difference between the read and write pointers, and timestamping circuitry receives the average difference and inserts timestamps into packets. Other embodiments and features are also disclosed.

主权项

1. A method for determining a latency of a network port, the method comprising:
generating a sampling clock at a sampling frequency, wherein a clock period of the sampling clock is distinct from clock periods of read and write clocks of the FIFO buffer; sampling a read pointer for a first-in-first-out (FIFO) buffer using an edge of the sampling clock; sampling a write pointer for the FIFO buffer using the edge of the sampling clock; obtaining a plurality of samples of the read pointer and a plurality of samples of the write pointer; and determining an average difference between the plurality of samples of the read and write pointers.