I am debugging some printing issues on a small LAN, and although I'm fairly sure the issues I'm facing are not related to cups itself, I have been tinkering with the printing protocols that both cups and my printers (Konica Minolta Bizhub C224E and C3350) understand. That made me wonder: is it just a matter of knowing which protocols your printers support, or is there any hierarchy between them? From the extensive reading I did, I seem to be able to deduce that LPD is fairly old and IPP(14) the 'new kid on the block', but does this new protocol offer real benefits or not?
cups printing protocols: what's the difference between raw/jetdirect - ipp - ipp14 - lpd?
printing;cups;lpd;ipp
Thx to @RuiFRibeiro I found some resources on the AskUbuntu site and one of them was pointing to an obsolete cups.org FAQ, which led me to a link that I had missed before: https://www.cups.org/doc/network.html . This page lists the most important differences:AppSocket ProtocolThe AppSocket protocol (sometimes also called the JetDirect protocol, owing to its origins with the HP JetDirect network interfaces) is the simplest, fastest, and generally the most reliable network protocol used for printers. AppSocket printing normally happens over port 9100 and uses the socket URI scheme:socket://ip-address-or-hostnameInternet Printing Protocol (IPP)IPP is the only protocol that CUPS supports natively and is supported by most network printers and print servers. IPP printing normally happens over port 631 and uses the http (Windows), ipp, and ipps URI schemes:http://ip-address-or-hostname:port-number/resourceipp://ip-address-or-hostname:port-number/resourceipps://ip-address-or-hostname:port-number/resourceLine Printer Daemon (LPD) ProtocolLPD is the original network printing protocol and is supported by many network printers. Due to limitations in the LPD protocol, we do not recommend using it if the printer or server supports one of the other protocols. LPD printing normally happens over port 515 and uses the lpd URI scheme:lpd://ip-address-or-hostname/queue