Which of the following are true about TCP and IP? (Choose two.)
A. TCP is connectionless and IP is connection oriented.
B. TCP is reliable and IP is unreliable.
C. IP is connectionless and TCP is connection oriented.
D. TCP is unreliable and IP is reliable.
E. IP operates at the transport layer.
The Correct Answer and Explanation is:
The correct answers are:
B. TCP is reliable and IP is unreliable.
C. IP is connectionless and TCP is connection oriented.
Detailed Explanation (300+ words):
Transmission Control Protocol (TCP) and Internet Protocol (IP) are fundamental components of the Internet Protocol Suite, often referred to as TCP/IP. They work together to enable reliable communication over the internet, but they function at different layers and have distinct roles.
TCP: Connection-Oriented and Reliable
TCP operates at the transport layer (Layer 4) of the OSI model. It is considered connection-oriented, which means that before data is transmitted, a connection is established between the sender and the receiver using a three-way handshake process. This ensures that both parties are ready and agree to the parameters of the communication session.
TCP is also reliable. It guarantees the delivery of data by using sequence numbers, acknowledgments (ACKs), and retransmissions if packets are lost or arrive out of order. It ensures error detection and correction, meaning that the data will be delivered correctly and in the same order it was sent.
IP: Connectionless and Unreliable
IP operates at the network layer (Layer 3) of the OSI model. It is responsible for routing packets of data from the source to the destination across multiple networks. However, IP is connectionless, meaning it does not establish a connection before sending data. Each packet (or datagram) is treated independently and may take different paths to reach the destination.
IP is also considered unreliable because it does not guarantee delivery, order, or error checking of the packets. If packets are lost, duplicated, or arrive out of order, IP has no mechanisms to correct these issues. These responsibilities fall to protocols like TCP that operate above IP.
Why Other Options Are Incorrect:
- A. Incorrect: TCP is not connectionless, and IP is not connection oriented.
- D. Incorrect: TCP is reliable, not unreliable; IP is unreliable.
- E. Incorrect: IP operates at the network layer, not the transport layer.
Summary:
- TCP: Reliable, connection-oriented, transport layer.
- IP: Unreliable, connectionless, network layer.