CSC458H1 Lecture Notes - Lecture 8: Telnet
Document Summary
Drops are spaced out in time desynchronize tcp senders. Given multiple sender flows into a router. Active queuing mechanisms: end-to-end principle = keep functionalities at end hosts, power at end-hosts, genearl internet design principle ex. congestion control, pros: flexible, easy to change and innovate, cons: trusting the least trusted component. Not necessarily optimal, high overhead: drop-tail queuing problems, bursty loss. Tcp congestion control depend on packet loss as feedback/indicator. Tcp drives network into packet loss by continuing to increase sending rate. When link is congested many arriving packets face a full queue. Result: many flows divide sending rate in half many individual flows lose multiple packets. Feedback occurs only when buffer completely full. Even if buffer has been filling up for a while. Buffer filling increases rtt and variance in the rtt. Better to give early feedback, avoid bursty loss. Slow down 1 2 flows before buffer is full, not all of them: slow feedback.
