a) The Wikileaks website was hit with a massive distributed denial of service attack (DDoS) attack after the site published its first installment of US diplomatic cables. Describe 3 different ways in which such attacks can be launched. b) Host A wants to send a large file of F bits to host B securely (i.e., protect the confidentiality and integrity of packets). A and B are connected by two routers R1 and R2. A TCP flow is initiated by A towards B and all packets are forwarded by routers R1 and R2. We assume that A and B never exchanged information in the past and that there is no other communication channel between A and B. Is it possible for the routers (R1 or R2) to inject content in the TCP flow without causing a loss of any original packets sent from A to B? If yes, explain how. If no, explain why.