The standard port for unencrypted data transfer is 631.
The standard port for encrypted data transfer is 443. The same port is used for secure web sites, i.e. HTTPS.
The print data and associated attributes are encoded to a long byte stream and send through socket communication.
Every transfer is committed by a HTTP status code and an IPP status text. The HTTP status code, for example 200=OK or 404=Not found, tells about network connection. The IPP status text given in the result stream, like queued-in-device, job-processing or job-finished tells about job processing in device.