Sockets

Question 1

What is the purpose of the Java Networking Framework?

Answer 1

To enable java programs on different systems to interact with each other, and even call each others methods
through RMI.

Question 2

Which internet layer are Java Programs on? Which layer are the transport protocols on?

Answer 2

Application Layer. Transport Layer.

Question 3

Explain how TCP transmits data to another machine…

Answer 3

• Sets up an initial connection via a handshake with the recipient. Sender now has IP and Port number to sends to
  and vice versa.
• TCP can then send ordered packets along this connection, guaranteeing order and delivery.
• More computationally expensive than UDP.

Question 4

Explain how UDP transmits datagrams to another machine…

Answer 4

• Route to a specific IP and Port number.
• Is done in one go with no order.
• Delivery is not guaranteed and some data may be missing.
• Less computationally expensive and is quicker.

Question 5

What is the purpose of ports? How do they work?

Answer 5

Ports on a machine are assinged to applications. This means incoming data will has an IP and port number in order
to reach the relevant application on the destination machine.

Question 6

Explain how servers use sockets for TCP communication?

Answer 6

The server sets up a socket on a port. This socket listens for incomming connection requests. When a connection
request is recieved, the machine accepts, and redirects the connection to the appropriate port. A new socket is
then place on the original port for listening, and the server continues listening for new requests.