Demonstration of the IP address space exhaustion led to the consensus that there was enough time to design, engineer, and test a new protocol with enhanced functionalities instead of deploying a new protocol that just adds larger addresses. This represented a unique opportunity to fix the limitations related to the IPv4 addressing scheme and to develop a protocol to ensure reliable growth of the Internet over the next decades. The process took care of requirements from various industries, including the cable and wireless industries, electric power utilities, the military, corporate networks, Internet service providers (ISPs), and many others.
In 1993, a call for proposals (RFC 1550) was issued. Three were studied in detail: