Conference papers are published papers. General formal academic exchange conferences will publish conference proceedings, not periodicals. A periodical paper is a paper published in an academic journal. To put it simply, the conference papers have no serial number, just a collection of essays; However, periodical papers have CN number and ISSN number. CN is a unified number in China and ISSN is an international number, which belongs to a regular publication.
The definition of conference proceedings is generally that the author attends an academic conference, reads his own articles at the conference, and publishes the proceedings after the conference, such as the proceedings of SCI and EI conferences.