TCP Congestion Control
Window flow control: avoid receiver overrun
Dynamic window congestion control: avoid/control network overrun
- Observation: Not a good idea to start with a large window and dump packets into network
- Treat network like a black box and start from a window of 1 segment (“slow start”)
- Increase window size exponentially (“exponential increase”) over successive RTTs => quickly grow to claim available capacity.
- Technique: Every ack: increase cwnd (new window variable) by 1 segment.
- Effective window = Min(cwnd, Wrcvr)