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PCP a Savior or a Saboteur?. Presented by: Ao-Jan Su. New, is NOT necessarily Good!!. Not Accurate. Not Secure. End Point. Router Support. Try and Backoff. TCP, Vegas, RAP, Fast TCP, S-TCP High Speed TCP. DecBit, ECN, RED, AQM. Request and Set. PCP. ATM, XCP, WFQ, RCP.
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PCPa Savior or a Saboteur? Presented by: Ao-Jan Su
New, is NOT necessarily Good!! Not Accurate Not Secure End Point Router Support Try and Backoff TCP, Vegas, RAP, Fast TCP, S-TCP High Speed TCP DecBit, ECN, RED, AQM Request and Set PCP ATM, XCP, WFQ, RCP Additional Overhead
Accuracy • Probe results’ accuracy? • PCP’s probe test is similar to pathload [Jain and Dovrolis] • pathload underestimates the available bandwidth when there are multiple tight link • Longer paths suffer more • Clock Skew? • Timestamp is recorded at the receiver!
Efficiency • Criteria for Selecting Controls • Efficiency, Fairness, Distributedness and Convergence [AIMD paper] • Lack for link utilization analysis in the paper • Can’t avoid oscillation
Overhead • What is the impact of probe packets to the network? • Periodic probes • Proportional to the number of flows • For short (web) traffic, the overhead can be significant
Security • Also not mentioned in the paper • End hosts are easier to compromise than routers • Encourages DDoS attack