200 Networking interview questions and answers

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Networking interview questions and answers


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Networking interview questions - posted on March 20, 2014 at 03:05 PM by Nihal Singh

Q.1 Describe Domain Name System.

There are two types of client/server programs.

First is used directly by the user, such as e-mail, Second supports other application programs. The Domain Name System (DNS) is a supporting program that is used by other programs such as to find the IP address of an e-mail recipient.

Q.2 Describe Hierarchical Namespace.

In a hierarchical name space, each name is combination of several parts as:

Type of the organization.
Name of an organization.
Departments in the organization.

A central authority can assign the part of the name that defines the nature and name of the organization. The other things of the name the organization provides itself. The organization can add suffixes (or prefixes) to the name to define its host.

The company need not worry about the prefix if it is same as that of another organization because, even if part of an address is the same, the whole address is different.

Example:

Suppose central authority has given names ABC.com and XYZ.com to two separate organization but these organization can add prefix as career so the name becomes career.XYZ.com and career.ABC.com. The names are unique without the need for assignment by a central authority. The central authority controls only part of the name, not the whole.

Q.3 Define Fully Qualified Domain Name and Partially Qualified Domain Name.

In hierarchical name space, names are defined in an inverted-tree structure with the root at the top. The tree can have only 128 levels: level 0 (root) to level 127.

Each node in the tree has a label, which is a string with a maximum of 63 characters.
The root label is a null string (empty string). In this tree, all the labels have different name, which guarantee the uniqueness of the domain names.

A full domain name is a sequence of labels separated by dots (.). The domain names are always read from the node up to the root.

Fully Qualified Domain Name

If a label is terminated by a null string or empty string, it is called a fully qualified domain name (FQDN).

Partially Qualified Domain Name

If a label is not terminated by a null string, it is called a partially qualified domain name (PQDN). A PQDN starts from a node, but it does not end with the root.

What is transmission impairment?

Signals need transmission media for travel from one point to another. Transmission media are not perfect because it provides resistance. The imperfection causes signal impairment. This means that the signal at the beginning of the medium is not the same as the signal at the end of the medium. What is sent is not what is received. There are three causes of impairment are attenuation, distortion, and noise.

Q.5 Describe attenuation, distortion, and noise in brief.

Attenuation: When a signal travels through a medium, it loses some of its energy due to resistance of the medium. This loss of energy is called Attenuation. This is the reason why a wire carrying electric signals gets warm. Some of the electrical energy in the signal is converted to heat. To overcome for this problem, amplifiers are used to amplify the signal.

Unit of the decibel is used to find out if a signal has lost or gained strength. The decibel (dB) measures the relative strengths of two signals or one signal at two different points. If decibel is negative then a signal is attenuated and if positive signal is amplified.

Formula:

Where PI and P2 are the variable and the powers of a signal at points 1 and 2, respectively.

Distortion

When the signal travels through the medium from one point to another it may chance to change the form or shape of signal. It is called distortion.

Distortion can occur in a composite signal, made up of different frequencies. Each signal component has its own propagation speed through a travelling medium and, therefore, its own delay in reaching at the final destination. Means signal components at the receiver have phases different from what they had at the sender.

Noise

The third cause of impairment is Noise. Following types of noise are possible.

-Thermal noise.
-Induced noise.
-Crosstalk noise.
-Impulse noise.

These noise may corrupt the signal.

Thermal noise is produced due to the random motion of electrons in a wire which creates an extra signal not originally sent by the transmitter.
Induced noise comes from sources such as motors and other electronic appliances.
These devices act as a sending antenna, and the transmission medium acts as the receiving antenna.
Crosstalk is the effect of one wire on the other.
Impulse noise comes from power lines, lightning etc.

Q.6 Describe composite single.

Composite Signals are the combination of more than one sine waves. Simple sine waves can be used to carry electric energy from one place to another or we can use a single sine wave to send an alarm to a security center when a thief opens a door or window in the house.

A single frequency sine wave is not useful in data communications we need to send a composite signal. A composite signal can be periodic or non-periodic.

The figure of composite periodic signal is given below.

Q.7 Describe MIME

Electronic mail has a simple structure. It can send messages only in NVT 7-bit ASCII format. It cannot be used for those languages that are not supported by 7-bit ASCII characters so languages such as French, German, Hebrew, Russian, Chinese etc cannot use this format. Also, it cannot be used to send binary files or video or audio data.

We need a protocol that allows non-ASCII data to be sent through e-mail. So Multipurpose Internet Mail Extensions (MIME) is the answer. MIME transforms non-ASCII data at the sender site to NVT (Network Virtual Terminal) ASCII data and delivers them to the client MTA to be sent through the Internet. The message at the receiving side is transformed back to the original data. Main task of MIME is to transform non-ASCII data to ASCII data and vice versa.

MIME header

Multipurpose Internet Mail Extensions defines five types of header.

Q.8 SMTP is push protocol Justify your answer.

SMTP is a push protocol; it pushes the message from the client to the server. For sending email SMTP is used two times, between the sender and the sender's mail server and between the two mail servers. To send mail, a system must have the client MTA (Message transfer agents), and to receive mail, a system must have a server MTA. SMTP uses commands and responses to transfer messages between an MTA client and an MTA server. Commands are sent from the client to the server and Responses are sent from the server to the client. SMTP is not used in pulling the message.

Q.9 Describe the POP3 protocol.

Post Office Protocol, version 3 is used for accessing the message. POP3 is very simple protocol and has limited functionality. POP has different version but currently version 3 is used. A POP3 server listens on well-known port 110. POP3 supports two types of mode.

Delete Mode: In this mode, the mail is deleted from the mailbox after each retrieval.

Keep Mode. The mail remains in the mailbox after retrieval.

Q.10 Describe IMAP4 (Internet Mail Access Protocol) in detail.

This protocol is also used in Internet for accessing the mail. IMAP4 has more feature than POP3 and is more powerful.

Main difference in POP3 and IMAP4 are as follows.

Q.11 What is Anonymous FTP?

Some sites provide the functionality that user can access the file with limited access. To access these files, a user does not need to have an account or password. For using FTP, the user enters "anonymous" as a user ID and guest as password. Usually, you can enter anything as a password.

Q.12 What is User Agent?

User agent is a software that provides the service to the user to make the process of sending and receiving a message easier. The following are User Agent services.

 

Networking interview questions - posted on Feb 04, 2014 at 12:45 PM by Nihal Singh

Q.1 Describe Classful Addressing

Ans. IPv4 addressing uses the concept of classes. In classful addressing, the address space is divided into five classes:A, B, C, D, and E. We can find the class of an address when the given address is in binary notation or dotted-decimal notation.
Example
 

Q.2 Find the error, if any, in the following IPv4 addresses.

a. 200.56.045.78
b. 22.34.7.8.20
c. 75.45.279.14
d. 11100010.23.24.66

Solution

a. There must be no leading zero (045).
b. There can be no more than four numbers in an IPv4 address.
c. Each number needs to be less than or equal to 255 (279 is outside this range).
d. A mixture of binary notation and dotted-decimal notation is not allowed.

Q3.Describe how many types are wireless transmission?

In general we can divide five types of wireless transmission

1. The Electromagnetic Transmission
2. Radio Transmission
3. Microwave Transmission
4. Infrared Transmission
5. Light Transmission

1. The Electromagnetic Transmission

When electrons move, they create electromagnetic waves that can propagate through space and in a vacuum. The electromagnetic waves can be broadcast efficiently and received by a receiver some distance away.

2. Radio Transmission

Radio waves are easy to generate, can travel long distances, and can penetrate buildings easily, so they are widely used for communication. These waves can travel in all directions.

3. Microwave Transmission

Microwaves travel in a straight line, so if the towers are too far apart, the earth will get in the way. Thus, repeaters are needed periodically. The higher the towers are, the farther apart they can be. Unlike radio waves at lower frequencies, microwaves do not pass through buildings well.

4. Infrared Transmission

It is used for short-range communication. The remote controls used for televisions, VCRs, and stereos, use infrared communication. They are relatively directional and can not pass through solid objects.

5. Light Transmission

These types of wave can easily effected by wind and temperature changes. They normally work well on sunny days.

Q.4 Explain Random Excess Method.

In Random Excess Method, any station can send the data at any time without the permission of other station. At any time, if a station has information to send to other station, it uses a specific method defined by the protocol to make a decision on whether or not to send.

There is no scheduled time for a station to transmit the data that is why it is called Random Excess Protocol. Random protocol has the following types.

 

Q5.Explain Channelization in networks.

Channelization is a multiple-access method in which the available bandwidth of a link is shared in time, frequency, or through code, between different stations. There are three basic approaches to achieve channelization.

 

Q.6 Describe FDMA and TDMA in short.

In frequency-division multiple access (FDMA), the available bandwidth is divided into frequency bands. Each station is allocated a band to send its data. Different frequency bands are used by different stations.

In time-division multiple access (TDMA), the stations share the bandwidth of the channel in time. Each station is allocated a time slot during which it can send data. Each station transmits its data in is assigned time slot.


FIG: TDMA

Q.7 Explain CDMA in wireless networks.

CDMA differs from FDMA and TDMA because only one channel occupies the entire bandwidth of the link and also there is no timesharing. In CDMA a code is available for every station wanting to send the data. In this protocol the assigned codes have two properties.

1. If we multiply each code by another, we get zero.
2. If we multiply each code by itself, we get the number of stations.

So suppose there are three stations and code and data are (c1, d1), (c2, d2), (c3, d3) respectively. The data that go on the channel are the sum of all these terms. Any station wanting to receive data from one of the other two, multiplies the data on the channel by the code of the sender. For example, suppose stations 1 and 2 are talking to each other. Station 2 wants to hear what station I is saying. It multiplies the data on the channel by cl the code of station 1.

Because (cl . cl) is 3, but (c2 . cI) and (c3 . cI) are all Zero, station 2 divides the result by 3 to get the data from station 1.

Q.8 Describe the functionality of data link layer.

Data Link Layer is the second layer from the bottom in OSI model. This layer has two main functions

• Data link control
• Media access control.

Data link control provides the functionality of include framing, flow and error control that provide smooth and reliable transmission of frames between nodes. Media Access Control (MAC) handles the sharing of link.

Q.9 Explain Stop-and-Wait Automatic Repeat Request for noisy channel.

In this protocol the sending device keeps a copy of the last frame transmitted until it receives an acknowledgment for that frame. A data frames uses a sequence number; an ACK frame uses an acknowledgment number. The sender has a control variable, which we call Sn (sender, next frame to send), that holds the sequence number for the next frame to be sent (0 or 1).

Q.10 what is the difference between Pure ALOHA and Slotted Aloha protocol?

In Pure Aloha, station can send data in a continuous time manner whereas in Slotted Aloha, time is divided in slots. Pure ALOHA doesn't check whether the channel is busy before transmission. In slotted ALOHA, a frame can be sent only at fixed times, whereas in pure ALOHA, you can send any time. Pure ALOHA has a vulnerable time of 2 x Tfr. Whereas in Slotted ALOHA vulnerable time = Tfr {Tfr: Average transmission time for a frame} .

Download Networking interview questions and answers
Comment on Data Encryption Standard (DES) weakness and strength.

The Data Encryption Standard (DES) is a symmetric key block cipher which takes 64-bit plaintext and 56-bit key as an input and produces 64-bit cipher text.............
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Describe the Packet Format of ARP (Address Resolution Protocol)
What are the advantages of IPv6 over IPv4?
What are the different design goals of ATM?

If you are a victim of Denial of Service (Dos) then what you do?

The function of a denial of service attack is to flood its target machine with too much traffic and prevents it from being accessible to any other requests or providing services..............
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Networking interview questions - posted on June 27, 2013 at 16:45 PM by Kshipra Singh

1. Differentiate between hub and switch.

a.) Hub is a layer 1 device while Switch is layer 2 device.
b.) Hub works on single collision and single broadcast domain while switch works on per port collision and single broadcast domain.

2. What is FQDN?

- FQDN is the abbreviation for Fully Qualified Domain Name.
- It contains both the hostname and a domain name.
- It uniquely identifies a host within a DNS hierarchy

3. Tell us something about LMHOSTS files.

- It is a text file that resolves NetBIOS names to IP addresses.
- It can be compared with the HOSTS file which is a static method of resolving domain names into IP addresses.
- LMHOSTS files must be manually configured and updated.

4. What are the main qualities of an effective and efficient network?

a. Performance
b. Reliability
c. Security

5. What are 10Base2, 10Base5 and 10BaseT Ethernet LANs?

10Base2 -
- It is an Ethernet term which means a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with a contiguous cable segment length of 100 meters and a maximum of 2 segments.

10Base5
- It is an Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with 5 continuous segments not exceeding 100 meters per segment.

10BaseT
- It is an Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling and twisted pair cabling.

6. What is anonymous FTP? What is its use?

- It is an FTP that enables the users to connect to a host without a valid login and password.
- The login used is anonymous or guest, with the password usually requesting the user's ID.
- It enables a large number of users to access the files on the host without needing to set up a login for all of them.
- It exercises a strict control over the areas an anonymous user can access.

7. Which factors mark the reliability of the network?

a. Frequency of failure
b. Downtime / Time taken for recovery.

8. Name the factors that tell us about the security of the network.

a. Virus attacks on the system.
b. Unauthorized access to the system.

9. Define Bandwidth and Latency?

- Bandwidth/ Throughput – It means the number of bits which can be transmitted over the network in a specified time.
- Latency – It is the time taken by a message to travel from one side to another.

Bandwidth and latency describe the performance of a network.

10. What is point to point link?

- Direct connection between two computers on a network is called as point to point link.
- No other network devices other than a connecting cable are required for point to point connection.
- The cable connects the NIC card of both the devices.

11. When is a switch said to be congested?

- Sometimes a switch receives the packets faster than they can be accommodated in the shared link. These packets are stored in the memory for sometime.
- However, after sometime the buffer space will exhaust and some packets will start getting dropped off.
- The switch is called as congested in this state.

12. Explain a.) Uni-casting, b.) Multicasting and c.) Broadcasting

a.) Uni-casting - Message is sent from a source to a single destination node.
b.) Multicasting - Message is sent from a source to some subsets of other nodes.
c.) Broadcasting - Message is sent from a source to all the nodes in the network.

13. What are the various types of Multiplexing?

The various types of multiplexing are:
a. Frequency Division Multiplexing (FDM)
b. Time Division Multiplexing (TDM)
i. Synchronous TDM
ii. Asynchronous TDM
c. Wave Division Multiplexing (WDM)

14. Which layers of OSI are referred to as network support layers?

The following 3 layers of OSI are referred to as network support layers:

a. Physical Layer
b. Data link Layer and
c. Network Layers

15. Which layers of OSI are referred to as user support layers?

The block of user support layers consists of:
a. Session Layer
b. Presentation Layer and
c. Application Layer

16. What does the Data Link Layer do?

- The Data Link Layer transforms the physical layer to a reliable link.
It takes care of:

a. Node to node delivery.
b. Framing
c. Physical Addressing
d. Flow Control
e. Error Control
f. Access Control

17. What is NIC?

- NIC stands for Network Interface Card.
- It is a peripheral card attached to a PC to helps it connect to a network.
- The MAC address of the card helps the network in identifying the PC.

18. What are the responsibilities of Network Layer?

- The Network Layer aids in source-to-destination delivery of packet across multiple networks.
- It performs:
a. Logical Addressing
b. Routing

19. Name the various error detection methods.

The various error detection methods are:
a. Vertical Redundancy Check (VRC)
b. Longitudinal Redundancy Check (VRC)
c. Cyclic Redundancy Check (VRC)
d. Checksum

20. . What is Bit Stuffing?

- Bit stuffing means adding one extra 0 whenever five consecutive 1s follow a 0.
- This is done so that the pattern 0111110 is not mistaken for a flag.

21. How does dynamic host configuration protocol aid in network administration?

- In a large set up where it is difficult to manually configure the IP address of each system, dynamic host configuration protocol comes very helpful.
- Using this protocol, the administrator can create a pool of IP addresses which are called scopes. These can be then dynamically assigned to the systems.

Routing and Switching
What are Brute Force Attacks?

Brute forcing is a mechanism which is used by an attacker to break the encryption of data by applying a set of various key.............
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How do you use RSA for both authentication and secrecy?

RSA is a public key encryption algorithm. The RSA algorithms are...........
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Can you differentiate among encoding, encryption and hashing?

Encoding: Basically encoding is used to protect the integrity of data as it crosses through communication network to keep its original message.............
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If you have to generate a hash function then what characteristics are needed in a secure hash function?

A secure hash function should have the following characteristics:................
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What is digital signature? Differentiate between Physical and Digital Signature

A digital signature is an electronic analogue of a written signature; the digital signature can be used to provide assurance...........
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What is Authentication Header and how it provides the protection to IP header?

Basically Authentication Header protects IP header and provides the complete authenticity to the IP packets.............
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Explain SSL Protocol. How does it protect internet users from various threats?

The SSL protocol (Secure Socket Layer protocol) was originally developed by Netscape, to ensure security of data transported.............
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What is PIX firewall security? How does it differ from a firewall?

PIX (Private Internet Exchange)...........
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What are Malware? Explain different types of Malware

Malware is a software program which is developed to destroy a computer system..............
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What are replay attacks? Give an example of replay attack

Replay attacks are the network attacks in which an attacker spies the conversation between the sender and receiver..........
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If you have to ‘encrypt’ as well as ‘compress’ data during transmission then which would you do first and why?

Data should be transmitted over any communication network in such a way that the data integrity and authenticity.............
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What is the goal of Information Security in an organization?

Mainly there are three Information security goals in an organization: Confidentiality, Integrity and Availability..............
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What is Symmetric-Key cryptography and Asymmetric-Key cryptography?

Symmetric-Key Cryptography: Symmetric-key cryptography uses a single key for both encryption and decryption. Encryption and decryption algorithm are inverse of each other.............
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Explain the services provided by IP (Internet Protocol) - Addressing, Fragmentation, Packet timeouts and options

Latest answer: Addressing: For the purpose of delivering datagram packets, IP needs to know about the address of the destination. By including the host addressing, this task is carried out by IP. As IP operates in an internet, its systems are designed to accept the addressing of devices which are unique.............
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Explain the classes of IP address

Latest answer: IP addresses are organized into classes. For convenience of humans, IP addresses are expressed in the decimal format. Every number in each class is represented as binary to computers..................
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Define Broadcast, Unicast and Multicast.

Latest answer: Unicast: A term used in communication to describe a piece of information to send from one point to another. There are only sender and receiver................
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What is Network Mask?

Latest answer: A network mask is used for determination of what subnet an IP address belongs to. An IP address has network address and the host address.................
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Define Subnetting.

Latest answer: A subnet describes a set of networked computers which have common IP address routing prefix..................
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What is the User Datagram Protocol (UDP)?

Latest answer: User datagram protocol allows computer applications to send messages as datagram packets from source to destination on an Internet Protocol,..................
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Explain TCP Windowing concept.

Latest answer: TCP Windowing is a concept that is used for avoiding congestion in the network traffic..................
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What is the Domain Name System (DNS)? What are the advantages of it?

Latest answer: A hierarchical naming system for computer systems, services or for that matter any resource participating in the internet...................
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What is the TTL (Time to Live)? Why is it required?

Latest answer: TTL is a value in data packet of Internet Protocol. It communicates to the network router whether or not the packet should be in the network for too long or discarded.................
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Explain the use of Internet Control Message Protocol (ICMP)

Latest answer: Internet Control Message Protocol is one of the important protocols in the Internet Protocol suite. It is mainly used in operating system of networked computers..................
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What is the use of IGMP protocol?

Latest answer: Internet Group Management Protocol: - It allows internet hosts to participate in multicasting. The IGMP messages are used to learn which hosts is part of which multicast groups..............
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What are Ping and Tracert?

Latest answer: Ping and tracert are the commands used to send information to some remote computers to receive some information. Information is sent and received by packets..............
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Explain RSVP. How does it work?

Latest answer: Resource Reservation protocol is used to reserve resources across a network. It is used for requesting a specific Quality of Service (QoS) from the network...............
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Explain the concept of DHCP.

Latest answer: Dynamic Host Configuration Protocol is used assigning IP addresses to computers in a network. The IP addresses are assigned dynamically...............
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What are the differences between a domain and a workgroup?

Latest answer: In a domain, one or more computer can be a server to manage the network. On the other hand in a workgroup all computers are peers having no control on each other.............
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Explain how NAT works.

Latest answer: Network Address Translation translates and IP address used in a network to another IP address known within another network. A NAT table is maintained for global to local and local to mapping of IP’s................
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What is PPP protocol? Explain PPP packet format.

Latest answer: Point to Point protocol helps communication between 2 computers over a serial cable, phone line or other fiber optic lines. E.g. Connection between an Internet Service Provider and a host................
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What is IP Spoofing and how can it be prevented?

Latest answer: IP spoofing is a mechanism used by attackers to gain unauthorized access to a system. Here, the intruder sends messages to a computer with an IP address indicating that the message is coming from a trusted host...............
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Explain IP datagram, Fragmentation and MTU.

Latest answer: IP datagram can be used to describe a portion of IP data. Each IP datagram has set of fields arranged in an order. The order is specific which helps to decode and read the stream easily..............
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What is an application gateway?

Latest answer: An application gateway is an application program that runs on a firewall between two networks. An application gateway is used for establishing connection between client program and destination service..................
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Explain Circuit Level Gateway.

Latest answer: A circuit level gateway is used to find if a session in TCP handshaking is legitimate or not. It can be considered as a layer between application layer and transport layer..................
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What is 'Gateway Of Last Resort'?

A Gateway of Last Resort or Default gateway is a route used by the router when no other known route exists to transmit the IP packet. Known routes are present in the routing table.................
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What are switches? Explain the concepts of Layer-3 switches.

Latest answer: It is a device that connects multiple network segments.
A switch analyzes the MAC address and then determines where to send the data..............
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What is Router? Explain components of Routers.

Latest answer: The way switches connect multiple computers, a router connects multiple networks. Routers comprise of data consisting of large tables of networks and addresses..................
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Overview of OSI layer.

Latest answer: OSI stands for Open Systems Interconnection
The OSI reference model gives an overview of the layered communications and computer network protocol design...................
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Explain different layers in the OSI model.

Latest answer: Application Layer: Closest to the end user, Interact directly with the software application.
Presentation Layer: Translates application to network format, and vice versa, Works to transform data into the form that the application layer can accept, Formats and encrypts data to be sent across a network.........................
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Explain the concept and capabilities of Unicast IP Addresses.

Latest answer: It is an IP address that uniquely identifies a host in a network.
The datagram with a unicast IP address is received and processed by only a single host.
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What is IP Multicasting?

Latest answer: It is an IP address that identifies a particular group of hosts in network.
This group of hosts is called a multicast group..............
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Explain the classes of IP addresses. Why do we need them?

Latest answer: Class A:
Range: from 0.0.0.0 to 127.255.255.255.
Leftmost bit: 0.
First 8 bits: netid.
Remaining 24 bits: hostid..............
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What is Subneting? Explain the advantages of using Subneting.

Latest answer: Subneting is dividing a network into several subnets.
This is usually done for the following purposes:..................
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What is Superneting? Explain the concept of custom Subneting.

Latest answer: Supernetting or Classless Inter-Domain Routing (CIDR) : It is a way to aggregate multiple Internet addresses of the same class..............
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What is VLSM, Variable length subnet masking?

Latest answer: VLSM is a means of allocating IP addressing resources to subnets according to their individual need rather than some general network-wide rule................
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What is Data Fragmentaion? Explain how Data Fragmentaion works.

Latest answer: Fragmentation occurs when storage space is used inefficiently due to which storage capacity and performance is reduced................
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Explain the concepts and capabilities of IP Datagram.

Latest answer: Data transmitted over an internet using IP is carried in messages called IP datagrams. Like all network protocol messages, IP uses a specific format for its datagrams...................
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What is MAC address?

Media Access Control address is an identifier for assigned to most network adapters or Network Interface Cards by the manufacturer for the purpose of identification...............
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Describe the Packet Format of ARP (Address Resolution Protocol)?

The fields of the packet format of ARP are as follows:
-Hardware type: It is a 16-bit field . Each LAN has been assigned an integer based on its type. For example, Ethernet is given the type 1.
-Protocol type: This is a 16-bit field defining the protocol. For example, the value of this field for IPv4 protocol is 0800.
-Hardware length: This is an 8-bit field defining the length of the physical address in bytes. For example, for Ethernet the value is 6.
-Protocol length: This is an 8-bit field defining the length of the logical address in bytes. For example, for IPv4 protocol the value is 4.
-Operation: This is a 16-bitfield defining the type of packet. Two packet types are defined: ARP request (1), ARP reply (2).
-Sender hardware address: This is a variable-length field defining the physical address of the sender. For example, for Ethernet this field is 6 bytes long.
-Sender protocol address: This is a variable-length field defining the logical (for example, IP) address of the sender. For the IP protocol, this field is 4 bytes long.
-Target hardware address: This is a variable-length field defining the physical address of the target. For example, for Ethernet this field is 6 bytes long.
-Target protocol address: This is a variable-length field defining the logical (for example, IP) address of the target. For IPv4 protocol, this field is 4 bytes long.

What are the advantages of IPv6 over IPv4?

the next generation IP, or IPv6 has some advantages over IPv4 that can be summarized as follows:
- Larger Address Space: An IPv6 address is 128 bytes long where IPv4 has 32-bit address only, this is a huge increase in the address space.
- Better Header Format: IPv6 uses a new header format which simplifies and speeds up the routing process because most of the options do not need to be checked by routers.
- New Options: IPv6 has new options to allow for additional functionalities.
- Allowance for extension: In IPv6 new technologies can easily embedded.
-Support For Resource Allocation: In IPv6, flow label has been added to enable the source to request special handling of the packet. This mechanism can be used to support traffic such as real-time audio and video.
-Support For More Security: The encryption and authentication options in IPv6 provide confidentiality and integrity of the packet.

What are the different design goals of ATM?

Asynchronous Transfer Mode (ATM) is the cell relay protocol.
The Design Goals of ATM are as follows:
- A technology is needed to take advantage of high rate transmission media and less susceptible to noise degradation for maximizing the data rates.
-The system must interface with existing systems and provide wide-area inter-connectivity between.
-The implementation of design must be cheaper enough so that everyone can afford it. If ATM is to become the backbone of international communications, as indeed, it must be available at low cost to every user who wants it.
-The new system must be able to work with and support the existing telecommunication hierarchies.
- The new system must be connection-oriented to ensure accurate and predictable delivery.
- One objective is to move as many of the functions to hardware as possible (for speed) an eliminate as many software functions as possible (again for speed).

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Discussion Board
Networking interview questions and answers.

What is the role of Pseudo tty?
Pseudo tty -false terminal - it enables external machines to connect through Telnet or rlogin. No connection can be made without a pseudo tty.

Explain External Data Representation.
It is a method of encoding data within an RPC message. It is used to ensure that the data is not system-dependent.

Differentiate between interior and exterior neighbour gateways.
- Interior gateway - connects LANs within an organization
- Exterior gateway - connects the organization to the outside world.

Honey 12-7-2011 06:48 AM

Networking interview questions and answers.

Explain SLIP.
SLIP - Serial Line Interface Protocol, is a protocol used for transmission of IP datagrams across a serial line.

What do you mean by Multi-homed Host?
- It is a multiple network interface that requires multiple IP addresses.

What is multicast routing?
Multicasting - Sending a message to a group.
Multicast routing- Routing algorithm of sending message to a group.

What is the role of OSI Reference Model?
It provides a framework for discussing network operations and design.

Arun 12-7-2011 06:47 AM

Networking interview questions and answers.

In which layer does the frame relay operate?
Frame relay - packet switching technology, operates in the data link layer.

Explain Gateway.
Gateway - operates at the upper levels of the OSI model. It translates information between two absolutely different network architectures or data formats.

What are the different ways of data exchange?
a. Simplex
b. Half-duplex
c. Full-duplex.

Magan 12-7-2011 06:46 AM

 

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