Suppose that CatLitterInBulk, an online retailer, is subjected to a distributed denial of service (DDOS) attack. CatLitterInBulks web retail system is comprised of 100 web servers and the attacker recruits 50 zombie devices to constantly send 60-byte SYN packets to the CatLitterInBulks web servers.

Suppose that each of CatLitterInBulks servers maintains a table for 256 TCP connection requests, and that in response to a SYN, these servers send a SYN-ACK packet four times, at t = 32 second time intervals, then purge the request from the table if no reply is forthcoming.

i. What is the total connection capacity of CatLitterInBulks servers?

ii. In packets/second what is the rate at which SYN packets will fill CatLitterInBulks connection tables?

iii. How many packets/second does each zombie, therefore, need to send? (2 marks) iv. How much bandwidth does each zombie need?