TCP cubic
also: CUBIC
TCP CUBIC is a modern TCP congestion control algorithm designed for high-speed, long-distance networks that adapts faster to bandwidth changes than traditional TCP Reno.
TCP CUBIC is a congestion control algorithm used by the TCP protocol to manage data transmission rates over networks. It adjusts the sending rate based on packet loss and delays, allowing senders to fill available bandwidth efficiently without overwhelming the network.
Unlike older algorithms like TCP Reno, CUBIC uses a cubic polynomial function to increase the congestion window (the amount of data sent before waiting for acknowledgment). This approach makes CUBIC perform better on high-bandwidth, high-latency connections—common in modern long-distance and intercontinental networks.
Example: When downloading a large file over a fast intercontinental link, CUBIC will quickly probe for available bandwidth after a loss event, then maintain high throughput more efficiently than Reno would. It's the default congestion control algorithm in modern Linux kernels.