Ans:

IP Address Classes

IP addressing supports three different commercial address classes; Class A, Class B, and Class C.

IN a class A address, the first octet is the first octet is the network portion, so the class A address of, 10.1.25.1, has a major network address of 10. Octets 2, 3 and 4 (the next 24 bits) are for the hosts. Class A addresses are used for networks that have more than 65,536 hosts (actually, up to 16,581,375 hosts!).

In a class B address, the firs two octets are the network portion, so the class B address of, 172.16.122.204, has a major network address of 172.16. Octets 3 and 4 (the next 16 bits) are for the hosts, Class B addresses are used for networks that have between 256 and 65, 536 hosts.

In a class C address, the first three octets are the network portion. The class C address of, 193.18.9.45, has a major network address of 193.18.9. Octet 4 (the last 8 bits) is for hosts. Class C addresses are used for networks with less than 254 hosts.

Ans: Connection establishment (Three way hand-shaking):-

TCP transmit data in full duplex mode. When ture TCPs on true machine are connected then they are able to send segment to each other simultaneously. This implies that, each TCP must initialize communication and get approval for the other TCP before and data transfer.

To establish connection there are four steps. But the third and second steps can be combined to create a three step connection called three way hand-shaking.

Steps:-

(a) The client sends the first segment a SYN segment. (Synchronization). The segment include the source and destination port no. The segment also contains the client initialization sequence no. (ISN).

(b) The server sends the second segment a SYN and an Acknowledge (Ack). Segment. This segment has a dual purpose.

• It acknowledge the receipt of the first segment
• Initialization segment for the server.

(c) The Client sends the Acknowledge (Ack)s segment.

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