Question

When you develop an application, you must choose one of the available transport-layer protocols. How do you make this choice? And, if you have to provide secure transmission for this application data, how it can be achieved?

Answer 1

When you develop an application, you must choose one of the available transport-layer protocols. How do you make this choice? And, if you have to provide secure transmission for this application data, how it can be achieved?

Answer:

            The internet has two main protocols in the transport layer namely TCP (Transmission Control Protocol) and UDP (User Datagram Protocol ). TCP is a connection oriented protocol and UDP is a connectionless protocol.

Choice of protocol for the application:

· TCP is the best choice. TCP is designed to provide a reliable end-to-end byte stream over an unreliable internet work. An internet work differs from a single network because different parts may have different topologies, packet sizes, band widths etc. TCP was designed to adapt to properties of the internet work and to overcome the failures.

· TCP guarantees that the recipient will receive the packets in the correct order by numbering it. After receiving the packet, the receiver will sent acknowledgement message back to the sender. If the sender doesn’t get this acknowledgement message, it will resent the same packet again to the receiver.

· TCP is slower than UDP, but guaranteed delivery of data packets occur in case of TCP.

· All TCP connections are full duplex and point to point. It does not support multicasting or broadcasting.

· When an application passes data to TCP, it may send it immediately or buffer it at its discretion.

· Another feature of TCP service is regarding urgent data transfer. When the urgent data are received at the destination, the receiving application is interrupted, so it can stop whatever it was doing and read the data stream to find the urgent data.

Security:

Security controls exit for network communications at each layer of TCP/IP. In TCP each packets are checked for errors. There is no loss of data or any type of corruption of data happens for TCP. The secure number and acknowledgement number fields provide more security for the data transmission through TCP.