The Internet Printing Protocol (IPP) does not only support printing, but also scanning, as there are many printers which also have a scanner (multi-function (MF) devices). Both CUPS and the developer tool ippserver emulate IPP network printers but not IPP scanners and so they cannot serve as a server to share a local scanner.
This task is about adding the scan server functionality. If you have a scanner connected locally (and it scans via SANE), share it as an IPP scanner, advertising itself and accepting jobs using the IPP driverless scanning standard. In contrary to SANE-based network scanning clients with any operating system, also phones or IoT devices can scan on your shared scanner.
Also old hardware can be recycled to a modern MF device, and we have a sample implementation to motivate manufacturers to adopt IPP scanning.
This server software will be a so-called Scanner Application, a sample implementation of the future form of scanner drivers, easily packageable in sandboxed, distribution-independent package formats like Snap.
Till Kamppeter, Project Leader OpenPrinting (till at linux dot com), SANE upstream developers TBD
C programming, DNS-SD, IPP