Networking Question and Answer

Q: What is TCP?
A: TCP stands for Transmission Control Protocol. It is a connection-based protocol that provides a reliable flow of data between two computers.
Q: What is UDP?
A: UDP stands for User Datagram protocol. It is a protocol that sends independent packets of data, called datagrams, from one computer to another with no guarantees about arrival. UDP is not connection-based like TCP.
Q: How does UDP differ from TCP?
A: TCP is connection based and guarantees that the data arrival whereas UDP is connection less and does not guarantee the arrival of data. This, TCP is more reliable that UDP.
Q: What is a Port?
A: A port is a number that represents a logical address which is used to identify the application to which the data has to be delivered.
Q: Can you explain in more detail?
A: Generally speaking, a computer has a single physical connection to the network. All data destined for a particular computer arrives through that connection. However, the data may be intended for different applications running on the computer. So how does the computer know to which application to forward the data? Through the use of ports.
Q: What is an IP Address?
A: IP Address is a 32 bit number used to identify a computer on a network.
Q: Can a computer have only one IP address?
A: No, Actually an IP address is used to identify a network node, if a computer has more than one network adaptor/network card, it can have more than one IP address.
Q: How many bits are used to represent a port?
A: 16 bits.
Q: What is a socket?
A: A socket is one end-point of a two-way communication link between two programs running on the network. A socket is identified by a The IP address of the computer to which the data is to be delivered and the port number of the application in that computer to which the data is to be delivered.

Q: What is the numeric range for port numbers?
A: Port numbers range from 0 to 65,535 because ports are represented by 16-bit numbers.
Q: What range of port numbers is reserved for system services?
A: Port numbers ranging from 0 – 1023.
Q: What are they reserved for?
A: They are reserved for use by well-known services such as HTTP and FTP and other system services. These ports are called well-known ports.
Q: What is OSI Model?
A: OSI stands for Open Systems Interconnection Basic Reference Model. It is a layered, abstract description for communications and computer network protocol design.
Q: What are the different layers in OSI Model?
A: OSI Model consists of the Application, Presentation, Session, Transport, Network, Data Link, and Physical layers.
Q: What is a Layer in OSI Model?
A: A layer is a collection of related functions that provides services to the layer above it and receives service from the layer below it.
Q: Explain Application Layer?
A: Application layer interface directly performs application services for the application processes; it also issues requests to the presentation layer.
Q: What is Presentation Layer?
A: The presentation layer establishes a context between application layer entities.
Q: What is Sessions Layer?
A: The session layer controls the dialogues/connections (sessions) between computers. It establishes, manages and terminates the connections between the local and remote application.
Q: What is Transport Layer?
A: The transport layer provides transparent transfer of data between end users, providing reliable data transfer services to the upper layers.
The transport layer controls the reliability of a given link through flow control, segmentation/desegmentation, and error control. Some protocols are state and connection oriented. This means that the transport layer can keep track of the segments and retransmit those that fail.
Q: What is Network Layer?
A: The network layer provides the functional and procedural means of transferring variable length data sequences from a source to a destination via one or more networks, while maintaining the quality of service requested by the Transport layer.
Q: What is Data Link Layer?
A: The data link layer provides the functional and procedural means to transfer data between network entities and also detects and possibly correct errors that may occur in the physical layer.
Q: What is Physical Layer?
A: The physical later are the physical hardware used like network cables, network cards etc..
Q: What is simplex communication?
A: In Simplex communication all data flows only in one direction.
Q: What is Duplex Communication?
A: In Duplex communication, data flows in both directions but at a time only in one direction.
Q: What is full duplex communication?
A: In Full Duplex communication data flows parallel in both directions.