935 B
lec11
TCP Congestion CControl
Additive increase & Multiplicative decrease
Sender increases window size until a loss happens. * Additively: increase by 1 every round-trip-time until a loss is detected. * Multiplicative decrese: cut window size in half
Sender limits the transmission by changing the size of it's congestion window. The sender detects loss with one of two methods: * Timeout * Triple Duplicate ACK's
General Fairness
TCP Fairness
Say we have two competing sessions: * additive increase slope of 1, as throughput increases * multiplicative decrease lowers throughput proportionally
UDP Fairness
Certain types of applications won't be be rate limited by TCP fairness. Streaming video for instance won't since we just want to throw data across as much as possible. This also means we have to account for loss and tolerate it when it does happen because UDP doesn't account for loss anyway.