Final answer:
VoIP, or Voice over Internet Protocol, is the service that enables the transmission of voice over an IP network through the conversion of analog signals into digital packets.
Step-by-step explanation:
The service that defines the protocols and technologies for transmitting voice packets over an IP network is Voice over Internet Protocol (VoIP). VoIP is a group of hardware and software technologies that deliver voice communications and multimedia sessions over the Internet. Unlike traditional phone systems that use circuit-switched telephony, VoIP converts analog voice signals into digital packets, which are then transmitted over the internet or any modern IP network.
To ensure that the voice communication is clear and uninterrupted, Quality of Service (QoS) mechanisms can be implemented, which manage the packet traffic to provide stable and predictable voice quality.