Computer Networking Questions Series 5

Suppose that everyone in a group of N people wants to communicate secretly with the N–1 others using symmetric key cryptographic system. The communication between any two persons should not be decodable by the others in the group. The number of keys required in the system as a whole to satisfy the confidentiality requirement is
A 2N
B N(N – 1)
C N(N – 1)/2
D (N – 1)2


Which of the following transport layer protocols is used to support electronic mail?
A SMTP
B IP
C TCP
D UDP


The transport layer protocols used for real time multimedia, file transfer, DNS and email, respectively are:
A TCP, UDP, UDP and TCP
B UDP, TCP, TCP and UDP
C UDP, TCP, UDP and TCP
D TCP, UDP, TCP and UDP