This document discusses service discovery mechanisms for the Application-Layer Traffic Optimization (ALTO) protocol. It proposes using mechanisms like DHCP, DNS, provisioning, manual configuration, or multicast/broadcast to discover ALTO servers. The document has merged previous individual drafts and seeks adoption as a working group item to align ALTO service discovery with the main ALTO protocol framework. Feedback was addressed, including a suggestion to use DHCP for access network domain names, which was added as an option.