Network definition: Latency describes the time required to transmit data or to communicate between two parties. In data networking, it corresponds to the one-way delay between two points (contrasted with the round-trip time (RTT)). Application definition: The term latency has been used to describe the degree of delay added from the original source to the screen. Different level of latency (low latency, ultra-low latency) can be achieved on OTT streaming based on the protocols and technologies involved.