csnotes/cst311/lec/lec11.md
2018-10-03 19:07:31 -07:00

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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. That being said we do have to tolerate loss since UDP doesn't account for data loss on the line in any significant manner.