In modern optical communication systems, optical modules serve as critical components for high-speed data transmission, and their performance optimization relies heavily on Clock and Data Recovery (CDR) technology. Clock and Data Recovery (CDR) is a core function that ensures stable, error-free transmission for optical modules. Therefore, by default SFP+ modules don't have CDR, and XFP modules must have CDR. (3) For transceivers used on a switch, there is little difference between the two.
[PDF Version]