- How many numbers of addresses are usable for addressing in a Class C network?
Answer: c. 254
The number of addresses usable for addressing specific hosts in each network is always 2 power N – 2 (where N is the number of rest field bits, and the subtraction of 2 adjusts for the use of the all-bits-zero host portion for network address and the all-bits-one host portion as a broadcast address. Thus, for a Class C address with 8 bits available in the host field, the number of hosts is 254
Class A 0.0.0.0 – 127.255.255.255
Class B 18.104.22.168 – 22.214.171.124
Class C 192.0.0.0 – 126.96.36.199
Class D 188.8.131.52 – 184.108.40.206
Class E 240.0.0.0 – 247.255.255.255
- How are the data units at Application layer is called?
- User Datagram
The data unit created at the application layer is called a message, at the transport layer the data unit created is called either a segment or an user datagram, at the network layer the data unit created is called the datagram, at the data link layer the datagram is encapsulated in to a frame and finally transmitted as signals along the transmission media
- What protocol is used by DNS name servers? Justify.
- UDP d. It can use any routing protocol
DNS uses UDP for communication between servers. It is a better choice than TCP because of the improved speed a connectionless protocol offers. Of course, transmission reliability suffers with UDP
- Which of the following is used to direct a packet inside an internal networks?
d None of the above
Routers are machines that direct a packet through the maze of networks that stand between its source and destination. Normally a router is used for internal networks while a gateway acts a door for the packet to reach the outside of the internal network