Free download networking interview questions

Application Layer. Which layers are network support layers? Data link Layer and c. Network Layers. Which layers are user support layers? Session Layer b. Presentation Layer and c. Which layer links the network support layers and user support layers?

The Transport layer links the network support layers and user support layers. What are the concerns of the Physical Layer? Physical layer coordinates the functions required to transmit a bit stream over a physical medium. Physical characteristics of interfaces and media b.

Representation of bits c. Data rate d. Synchronization of bits e. Line configuration f. Physical topology g. Transmission mode.

What are the responsibilities of Data Link Layer? The Data Link Layer transforms the physical layer, a raw transmission facility, to a reliable link and is responsible for node-node delivery. Framing b. Physical Addressing c. Flow Control d. Error Control e. Access Control. What are the responsibilities of Network Layer? The Network Layer is responsible for the source-to-destination delivery of packet possibly across multiple networks links. Logical Addressing b. What are the responsibilities of Transport Layer?

The Transport Layer is responsible for source-to-destination delivery of the entire message. Service-point Addressing b. Segmentation and reassembly c. Connection Control d. Flow Control e. Error Control. What are the responsibilities of Session Layer? The Session layer is the network dialog Controller. It establishes, maintains and synchronizes the interaction between the communicating systems.

Dialog control b. What are the responsibilities of Presentation Layer? The Presentation layer is concerned with the syntax and semantics of the information exchanged between two systems. Translation b. Encryption c. What are the responsibilities of Application Layer?

The Application Layer enables the user, whether human or software, to access the network. It provides user interfaces and support for services such as e-mail, shared database management and other types of distributed information services.

Network virtual Terminal b. Mail services d. Directory Services. What are the different link types used to build a computer network? Cables b. Leased Lines c. Last-Mile Links d. Wireless Links. What are the categories of Transmission media? Guided Media i. Twisted — Pair cable 1.

Shielded TP 2. Unshielded TP ii. Coaxial Cable iii. Fiber-optic cable b. Unguided Media i. Terrestrial microwave ii. Satellite Communication. What are the types of errors? Single-Bit error In a single-bit error, only one bit in the data unit has changed b. Burst Error A Burst error means that two or more bits in the data have changed. What is Error Detection? What are its methods? Data can be corrupted during transmission.

For reliable communication errors must be deducted and Corrected. Error Detection uses the concept of redundancy, which means adding extra bits for detecting errors at the destination. The common Error Detection methods are a. What is Redundancy? The concept of including extra information in the transmission solely for the purpose of comparison.

This technique is called redundancy. What is VRC? It is the most common and least expensive mechanism for Error Detection. In VRC, a parity bit is added to every data unit so that the total number of 1s becomes even for even parity. It can detect all singlebit errors. It can detect burst errors only if the total number of errors in each data unit is odd. What is LRC? In LRC, a block of bits is divided into rows and a redundant row of bits is added to the whole block. It can detect burst errors.

If two bits in one data unit are damaged and bits in exactly the same positions in another data unit are also damaged, the LRC checker will not detect an error. In LRC a redundant data unit follows n data units. What is CRC? CRC, is the most powerful of the redundancy checking techniques, is based on binary division.

What is Checksum? What are the Data link protocols? Data link protocols are sets of specifications used to implement the data link layer. The categories of Data Link protocols are. Asynchronous Protocols 2. Synchronous Protocols a. Character Oriented Protocols b. Bit Oriented protocols. Compare Error Detection and Error Correction: The correction of errors is more difficult than the detection.

In error detection, checks only any error has occurred. In error correction, the exact number of bits that are corrupted and location in the message are known. The number of the errors and the size of the message are important factors. What is Forward Error Correction? Forward error correction is the process in which the receiver tries to guess the message by using redundant bits.

Define Retransmission? Retransmission is a technique in which the receiver detects the occurrence of an error and asks the sender to resend the message. Resending is repeated until a message arrives that the receiver believes is error-freed. What are Data Words? In block coding, we divide our message into blocks, each of k bits, called datawords.

The block coding process is one-to-one. The same dataword is always encoded as the same codeword. What are Code Words?

The resulting n-bit blocks are called codewords. These codewords are invalid or illegal. What is a Linear Block Code? A linear block code is a code in which the exclusive OR addition modulo-2 of two valid codewords creates another valid codeword. What are Cyclic Codes?

Cyclic codes are special linear block codes with one extra property. In a cyclic code, if a codeword is cyclically shifted rotated , the result is another codeword. Define Encoder? A device or program that uses predefined algorithms to encode, or compress audio or video data for storage or transmission use. A circuit that is used to convert between digital video and analog video.

Define Decoder? A device or program that translates encoded data into its original format e. The term is often used in reference to MPEG-2 video and sound data, which must be decoded before it is output.

What is Framing? Framing in the data link layer separates a message from one source to a destination, or from other messages to other destinations, by adding a sender address and a destination address. The destination address defines where the packet has to go and the sender address helps the recipient acknowledge the receipt. What is Fixed Size Framing? In fixed-size framing, there is no need for defining the boundaries of the frames.

The size itself can be used as a delimiter. Define Character Stuffing? In byte stuffing or character stuffing , a special byte is added to the data section of the frame when there is a character with the same pattern as the flag. The data section is stuffed with an extra byte. This byte is usually called the escape character ESC , which has a predefined bit pattern. Whenever the receiver encounters the ESC character, it removes it from the data section and treats the next character as data, not a delimiting flag.

What is Bit Stuffing? Bit stuffing is the process of adding one extra 0 whenever five consecutive Is follow a 0 in the data, so that the receiver does not mistake the pattern for a flag. What is Flow Control? Flow control refers to a set of procedures used to restrict the amount of data that the sender can send before waiting for acknowledgment. What is Error Control? Error control is both error detection and error correction.

It allows the receiver to inform the sender of any frames lost or damaged in transmission and coordinates the retransmission of those frames by the sender.

Partial Mesh Topology: In this type of topology, most of the devices are connected almost similarly as full topology. The only difference is that few devices are connected with just two or three devices. Full Mesh Topology: In this topology, every node or device are directly connected with each other.

A large percentage of a network is made up of hardware. Problems in these areas can range from malfunctioning hard drives, broken NICs, and even hardware startups. Incorrect hardware configuration is also one of those culprits to look into. A common way of dealing with such a problem is to use repeaters and hubs because it will help regenerate the signal and therefore prevent signal loss. Checking if cables are properly terminated is also a must.

Instead of having to visit each client computer to configure a static IP address, the network administrator can apply dynamic host configuration protocol to create a pool of IP addresses known as scopes that can be dynamically assigned to clients.

Profiles are the configuration settings made for each user. A profile may be created that puts a user in a group, for example. Sneakernet is believed to be the earliest form of networking wherein data is physically transported using removable media, such as disk, tapes. IEEE, or the Institute of Electrical and Electronics Engineers, is an organization composed of engineers that issues and manages standards for electrical and electronic devices.

This includes networking devices, network interfaces, cablings, and connectors. Rights refer to the authorized permission to perform specific actions on the network. Each user on the network can be assigned individual rights, depending on what must be allowed for that user. A VLAN is required because at the switch level. There is only one broadcast domain. It means whenever a new user is connected to switch. This information is spread throughout the network.

VLAN on switch helps to create a separate broadcast domain at the switch level. It is used for security purposes. At present, IPv4 is being used to control internet traffic but is expected to get saturated in the near future. IPv6 was designed to overcome this limitation. It is the most commonly used public-key encryption algorithm in use today. Mesh topology is a setup wherein each device is connected directly to every other device on the network.

Consequently, it requires that each device has at least two network connections. The maximum allowable length for a network segment using Base-FX is meters. The maximum length for the entire network is 5 kilometers. The rule is used in 10Base2 and 10Base5 Ethernet architectures. In this rule, there can be a maximum of five segments in a network connected with four repeaters. Out of these five segments, only three segments can be populated with nodes.

The decoder is a type of circuit that converts the encoded data to its original format. It also converts the digital signal into an analog signal. Brouter is also known as Bridge Router. It is a device that acts as both a bridge and a router.

As a bridge can forwards data between the networks. It also routes the data to specified systems within a network. Corporate companies, educational institutions, government offices.

The OSI model was started in February In NVT is a set of pre-defined rules to very simple virtual terminal interaction. This terminal helps you to start a Telnet session. The source route is a sequence of IP addresses that helps you to identify the route a datagram. You can include the source route in the IP datagram header. Pipelining describes the sequencing of processes.

When any new task begins before an ongoing task is finished, it is called sequencing. It is a host that has multiple network interfaces that multiple IP addresses is called a Multi-homed Host. It is the protocol of the routers. It is the neighboring autonomous systems that help you to identify the set of networks that you will able to reach within or via each independent system.

It is a false terminal which allows you external machines to connect through Telnet or log in. Without this, no connection can take place. This component comes under the presentation layer. It is a three-step process that requires both the client and server to exchange synchronization and acknowledgment packets before the real data communication process starts.

Hamming code is a liner code that is useful for error detection up to two immediate bit errors. It is capable of single-bit errors. In Hamming code, the source encodes the message by adding redundant bits in the message. These redundant bits are mostly inserted and generated at certain positions in the message to accomplish the error detection and correction process. It consists of a 48 bit or bit address, which is associated with the network adapter. MAC address can be in hexadecimal format.

Analog signal is a continuous signal in which one time-varying quantity represents another time-based variable. These kind of signals works with physical values and natural phenomena such as earthquake, frequency, volcano, speed of wind, weight, lighting, etc.

A digital signal is a signal that is used to represent data as a sequence of separate values at any point in time. It can only take on one of a fixed number of values. This type of signal represents a real number within a constant range of values. Here are the main differences between Analog and Digital Signal:. A Metropolitan Area Network or MAN is consisting of a computer network across an entire city, college campus, or a small region.

This type of network is large than a LAN, which is mostly limited to a single building or site. Depending upon the type of configuration, this type of network allows you to cover an area from several miles to tens of miles. A modem modulator-demodulator is a device that modulates an analog signal to digital information.

It also decodes carrier signals to demodulates the transmitted information. The main aim of the Modem is to produce a signal that can be transmitted easily and decoded to reproduce the digital data in its original form. Skip to content. Report a Bug. Previous Prev. Next Continue. Home Testing Expand child menu Expand. SAP Expand child menu Expand. Web Expand child menu Expand. Must Learn Expand child menu Expand.

T specifies the type of the cable which is a twisted pair. POP is responsible for accessing the mail service on a client machine. POP3 works on two models such as Delete mode and Keep mode. It is a unique address means no two devices can have same MAC addresses. There are three ranges of IP addresses that have been reserved for IP addresses. They are not valid for use on the internet.

If you want to access internet on these private IPs, you must have to use proxy server or NAT server. A public IP address is an address taken by the Internet Service Provider which facilitates you to communication on the internet. This feature is generally found in Microsoft operating system. Anonymous FTP is used to grant users access to files in public servers. Users which are allowed access to data in these servers do not need to identify themselves, but instead log in as an anonymous guest.

A protocol is a set of rules which is used to govern all the aspects of information communication. First is directly used by the users and the second supports application programs. The Domain Name System is the second type supporting program that is used by other programs such as to find the IP address of an e-mail recipient. A link is connectivity between two devices which includes the cables and protocols used in order to make communication between devices.

These seven layers can be grouped into three categories:. The OSI physical layer is used to convert data bits into electrical signals and vice versa. On this layer, network devices and cable types are considered and setup. OSI session layer provides the protocols and means for two devices on the network to communicate with each other by holding a session.

This layer is responsible for setting up the session, managing information exchange during the session, and tear-down process upon termination of the session.

It is a set of protocol layers that is designed for exchanging data on different types of networks. The "netstat" is a command line utility program. The "ping" is a utility program that allows you to check the connectivity between the network devices. You can ping devices using its IP address or name. Sneakernet is the earliest form of networking where the data is physically transported using removable media. A switch receives packets faster than the shared link. It can accommodate and stores in its memory, for an extended period of time, then the switch will eventually run out of buffer space, and some packets will have to be dropped.

This state is called a congested state. In Networking, multiplexing is the set of techniques that is used to allow the simultaneous transmission of multiple signals across a single data link. Address sharing provides security benefit instead of routing. That's because host PCs on the Internet can only see the public IP address of the external interface on the computer that provides address translation and not the private IP addresses on the internal network.

JavaTpoint offers too many high quality services. Mail us on [email protected] , to get more information about given services. Please mail your requirement at [email protected] Duration: 1 week to 2 week. All Interview. Networking Interview Questions A list of top frequently asked networking interview questions and answers are given below 1 What is the network?

A network is a set of devices that are connected with a physical media link. In a network, two or more nodes are connected by a physical link or two or more networks are connected by one or more nodes. A network is a collection of devices connected to each other to allow the sharing of data. Example of a network is an internet. An internet connects the millions of people across the world. The types of topologies are: Bus: Bus topology is a network topology in which all the nodes are connected to a single cable known as a central cable or bus.

It acts as a shared communication medium, i. Bus topology is useful for a small number of devices. As if the bus is damaged then the whole network fails. Star: Star topology is a network topology in which all the nodes are connected to a single device known as a central device.

Star topology requires more cable compared to other topologies. Therefore, it is more robust as a failure in one cable will only disconnect a specific computer connected to this cable. If the central device is damaged, then the whole network fails. Star topology is very easy to install, manage and troubleshoot. Star topology is commonly used in office and home networks. Ring Ring topology is a network topology in which nodes are exactly connected to two or more nodes and thus, forming a single continuous path for the transmission.

It does not need any central server to control the connectivity among the nodes. If the single node is damaged, then the whole network fails. Ring topology is very rarely used as it is expensive, difficult to install and manage.

Mesh Mesh topology is a network topology in which all the nodes are individually connected to other nodes. It does not need any central switch or hub to control the connectivity among the nodes. Mesh topology is categorized into two parts: Fully connected mesh topology : In this topology, all the nodes are connected to each other.

Partially connected mesh topology : In this topology, all the nodes are not connected to each other. It is a robust as a failure in one cable will only disconnect the specified computer connected to this cable. Mesh topology is rarely used as installation and configuration are difficult when connectivity gets more.

Cabling cost is high as it requires bulk wiring. Tree Tree topology is a combination of star and bus topology. It is also known as the expanded star topology. In tree topology, all the star networks are connected to a single bus. Ethernet protocol is used in this topology. In this, the whole network is divided into segments known as star networks which can be easily maintained. If one segment is damaged, but there is no effect on other segments. Tree topology depends on the "main bus," and if it breaks, then the whole network gets damaged.

Hybrid A hybrid topology is a combination of different topologies to form a resulting topology. If star topology is connected with another star topology, then it remains star topology. If star topology is connected with different topology, then it becomes a Hybrid topology.

It provides flexibility as it can be implemented in a different network environment. The weakness of a topology is ignored, and only strength will be taken into consideration. A list of advantages of distributed processing: Secure Support Encapsulation Distributed database Faster Problem solving Security through redundancy Collaborative Processing 4 What is the criteria to check the network reliability?