RTTs

RTTs is commonly used to denote Round-Trip Time, the time it takes for a signal to travel from a sender to a destination and back. It is a measurement of network latency and is usually expressed in milliseconds. RTT is influenced by multiple delays, including propagation, transmission, processing, and queuing along the path. It is a key parameter for assessing interactive performance, quality of experience, and protocol behavior. RTTs can be measured with tools such as ICMP echo requests (ping), TCP RTT estimates based on timestamp data, or end-to-end measurements; traceroute can provide a hop-by-hop view and approximate RTTs to intermediate nodes. RTTs are often asymmetric, with forward and reverse paths exhibiting different delays.

In practice, RTT measurements inform congestion management, capacity planning, and performance optimization. Protocols such as TCP use RTT samples to adjust retransmission timeouts through algorithms like the Jacobson–Karels estimator. Higher RTTs or greater variability (jitter) can reduce the responsiveness of interactive applications and lower TCP throughput. Local networks typically report RTTs of microseconds to a few milliseconds, while paths across the Internet commonly range from tens to hundreds of milliseconds; satellite and other high-latency links can exceed several hundred milliseconds. RTTs can be affected by physical distance, link quality, routing changes, and congestion, and they are often monitored alongside jitter and packet loss to gauge overall network health.

RTTs also stands for Real-Time Text, a communication method in which characters appear on the recipient’s screen as they are typed. This near-immediate text transmission supports accessibility in telecommunications and emergency services, and can operate over traditional telephone networks or IP-based systems, using standards that govern timing and presentation of text.