LEDBAT (Low Extra Delay Background Transport) is a network congestion control protocol designed to provide low-priority traffic with the ability to use excess bandwidth while minimizing the impact on latency for higher-priority traffic. It is developed by Microsoft and is specifically designed for scenarios where background or non-essential data transfer is taking place alongside more time-sensitive or interactive traffic.
Here are some key characteristics and features of LEDBAT:
- Background Traffic: LEDBAT is particularly suitable for applications or services that involve non-critical or background data transfers. This could include file downloads, updates, backups, or other bulk data transfers.
- Low Latency Impact: LEDBAT is designed to be highly responsive to network congestion and adjusts its sending rate dynamically. When the network is under heavy load, LEDBAT reduces its data transfer rate to minimize the impact on more time-sensitive traffic, such as real-time communication or interactive applications.
- Adaptive Rate Control: LEDBAT uses an adaptive rate control mechanism that takes into account the round-trip time (RTT) of packets and the estimated bandwidth available. It strives to utilize any spare bandwidth in the network without causing undue latency for other traffic.
- Fairness: LEDBAT is designed to be fair to competing traffic. It aims to share available bandwidth fairly with other traffic types and yield to higher-priority traffic when necessary.
- Congestion Sensitivity: LEDBAT is highly sensitive to network congestion signals. It reduces its sending rate quickly when it detects congestion, allowing it to act as a good network citizen by minimizing the impact on other traffic.
- Windows Update Delivery Optimization: LEDBAT is often associated with Windows Update Delivery Optimization (WUDO), a feature in Windows operating systems. WUDO uses LEDBAT to download updates efficiently in the background without causing significant delays for users engaged in other activities.
The goal of LEDBAT is to strike a balance between utilizing available network bandwidth for background tasks and ensuring that latency-sensitive applications experience minimal disruption. It is part of efforts to improve the overall network performance and user experience, especially in scenarios where multiple types of traffic coexist on the same network.
