Question

You and a couple of friends have decided to use your probability knowledge to detect Denial-of-Service (DoS) attacks. To keep things simple, let's say that your detector only looks at the number of packets arriving in a short time window.l Under normal traffic, the number of packets X is Poisson(a). Under a DoS attack, the number of packets X is Poisson(B). Let Hy be the hypothesis that the traffic is normal and Hį be the hypothesis that a DoS attack is happening. (a) Determine the likelihood ratio L(x) = Pxh (2) Pxh (2) (b) Determine the log-likelihood ratio In(L (C) (where in represents the natural logarithm func- tion).

Please answer (a) and (b) and don't copy from other answers.

Answer 1

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• Soli Let X, X2 ... Xn nr.v. taken Ho. Traffic is Normal No. g pockets & is P(Q)) Hi! DoS attack is happening (Nog pockets xi's PCP)} Y2012 LCFC) = cəhdyt f00)=Pa) = 001, 12932- () Likelihood Rating - LCfanyes. [LCACIDAE che EX1 X De ha exi - n(B-2), Exil (10) llojl= -18) +231 1999/) is log Zikelihood folio