Some Mid-Term Thoughts • Wed Nov 2 – In class • 1 hour 15 minutes exam – Should not take more than 45 minutes • Allowed to bring in two cheat sheets – Fit in as much as you can – But not much point • Syllabus – Everything covered till today • i.e., Bellman Ford’s algorithms in Routing • About the exam format – Questions will not test whether you remember – You will not have to write long essays – Not be asked to write code – Will probably have • • • • Multiple choice questions True and false questions Some problems to solve Arguments about tradeoffs • Exact test format – Not yet decided • Some Examples: – (T/F) TCP sends a new packet whenever it gets an ACK (not a DupACK) from the receiver. – (T/F) A TCP sender starts a timer once a packet has been transmitted. – (T/F) Bandwidth constraint does not necessarily imply timing constraints – Argue in favor or against: Stop and wait is never better than GBN – Calculate expected latency when a proxy is, and is not, used for caching webpages. • The network, and relevant data will be provided – Write 2 advantages and 2 disadvantages for recursive and non-recursive DNS – Design a finite state machine for Go-Back-N – Calculate RTO for a given network (relevant data will be given) – Fill out an incomplete figure on TCP’s actions in certain conditions – Prove that TCP flows are fair to each other, irrespective of who starts first – Compute how many iterations will happen before the distance vector route converges. Questions?