A channel identifier is a value used to distinguish or match a channel entry within a particular system. In playlist and guide workflows, a matching identifier can connect an entry to its programme information. Its usefulness depends on consistent values; similar display names do not necessarily mean that two entries use the same identifier.
A practical example
A player may need the identifier in a playlist entry to match the identifier in an XMLTV guide. If the names look identical but the identifiers differ, the channel can play while its schedule remains blank in the guide.
A common misunderstanding
Do not casually change identifiers when tidying channel names. A cosmetic rename and a guide-matching identifier have different jobs, and altering the latter can break existing matches.
Related terms
Stable technical definition. Editorial approach