You can select from a variety of options under the Protocol. You could, for example, use the AirPrint protocol. This will provide you access to your network via ethernet, USB, and Wi-Fi. This protocol is supported by a variety of Canon printer types. You can also choose HP JetDirect for HP and other well-known printer brands in some instances. If you have an ancient printer, LPD-Line Printer Daemon may be a good choice. Internet Printing Protocol may be the best option for current printers.