TCP (Transmission Control Protocol) - Computer Science Engineering (CSE) MCQ

TCP is a transport layer protocol that provides reliable and ordered delivery of a stream of bytes between hosts communicating via an IP network.

A TCP receiver has a receive buffer that is used to store the unprocessed incoming packets in case the sender is sending packets faster than the processing rate of the received packets.

Data can flow both the directions at the same time during a TCP communication hence, it is full-duplex. This is the reason why TCP is used in systems that require full-duplex operation such as e-mail systems.

As TCP has to ensure ordered delivery of packets, sequence number and acknowledgement number are used to identify the byte number of the packet in the stream of bytes being transmitted.

One might expect the sequence number of the first byte in the stream to be 0, or 1. But that does not happen in TCP, Instead, the sender has to choose an Initial Sequence Number (ISN), which is basically a random 32 bit sequence of 0’s and 1’s, during the connection handshake.

• Elastic traffic has the ability of making adjustment of wide-ranging changes in delay and throughput across the internet and still meets the needs of the applications.
• It adjusts its throughput between end hosts in response to network condition. Network load or congestion may cause packet loss.
• TCP elastic traffic is generated by the traditional “data” applications in the Internet, such as web browsing, peer-to-peer file sharing, ftp, e-mail and other.
• These applications are built on top of TCP, which provides reliable transfers and adjusts the sending rate to the network conditions to achieve the maximum possible throughput, a feature that makes TCP flows to be called “elastic”.
• From the point of view of the network, TCP elastic traffic requires the maximum possible throughput above a minimum value, a network service that we call the Minimum Throughput Service (MTS).

IPv4 header:

Fragment offset, Flags (like MF), and Identification (Identifier) are related to fragmentation.
Therefore TOS is not related to fragmentation

Concept:
TCP/IP Model:
The TCP/IP Model is used to determine how a computer connects to the internet and how data is transferred between them. When several computer networks are joined together, a virtual network is created. The TCP/IP protocol was designed to make long-distance communication easier.
Four Layers of TCP/IP model:
Application Layer:
Allow access to network resources.
Transport Layer:
To provide a reliable process to process message delivery and error delivery.
Network layer or Internet Layer:
To move packets from source to destination. It provides internetworking.
Network Interface:
Responsible for the transmission between two devices on the same network.
OSI layer to TCP/IP layer:

TCP stands for Transmission Control Protocol a communications standard that enables application programs and computing devices to exchange messages over a network. It is designed to send packets across the internet and ensure the successful delivery of data and messages over networks.
Hence the correct answer is Transmission Control Protocol.

Transmission Control Protocol (TCP):

• TCP is a reliable connection-oriented protocol that can be used in any application where reliability is important. 
• TCP explicitly defines to provide a connection establishment, data transfer, and connection teardown phases to provide a connection-oriented service.
• TCP connections are full-duplex
• TCP uses GBN and SR protocols to attain reliability. Therefore it has selective acknowledgment. 
• It provides end-to-end communication due to the port number of source and destination. 
• TCP connections are byte streams. 

Hence statement I is correct