Essential Networking Interview Questions Part – 3
Q – 1 Why did you choose career in network engineering?
Ans- There are many reasons for this choice. It is a perspective area with bright future and great possibilities of career growth. The salaries for engineers are exceptional too. What more, the competition is not so tough like in other fields.
☛ Exceptional computer intelligence and great predispositions to become a network engineer
☛ Love to do the job, motivation and enthusiasm for doing it
☛ Belief in huge perspective of this field nowadays.
“I love to work with networks. I liked it since my childhood. I was an administrator of local network we had back then. I believe this area is very perspective and important in society, because we have networks everywhere right now. To work on the security and effectiveness of it makes me proud and happy in my daily life.”
Q – 2 How can you describe network topology?
Ans- There are many ways to discover network topology and most of the ways you know determine your experience in the field. First, you can ping random IP addresses. If you do a tracert, you can discover router IP addresses. You can install a network traffic packet analyzer to read some of the traffic that passes between segments of the network. You can run an SNMP scanner and attempt to find open systems. Even at a basic level, you can plug a laptop into open data ports to see if you can connect to various servers and other desktops.
Q – 3 Do you know about some basic ways to speed up network performance?
Ans- There are several ways to improve network performance. You can first make sure you disable peer-to-peer downloading and torrents. Some companies restrict media streaming such as YouTube and Pandora. You can also add compression to files to reduce the amount of bandwidth used. Another area where some network admins make mistakes is timed backups and large data transfers. Make sure your backups are done during slow network times, which is usually overnight when the office is closed.
Q – 4 Tell me have you ever worked in heterogeneous environments and multiple server and client platforms?
Ans- The obvious answer to this question is yes or no, but you should elaborate if the answer is yes. Most networking environments use a combination of Windows and Linux servers and desktops. Usually, network engineers prefer Linux servers and work with Windows and Linux desktops. Occasionally, you might have some Mac desktops as well to work with.
Q – 5 Tell me what is SLIP (Serial Line Interface Protocol) in network engineering?
Ans- It is a very simple protocol used for transmission of IP data-grams across a serial line.
Q – 6 Tell me what is RIP (Routing Information Protocol)?
Ans- It is a simple protocol used to exchange information between the routers.
Q – 7 Do you know what is source route?
Ans- It is a sequence of IP addresses identifying the route a datagram must follow. A source route may optionally be included in an IP datagram header.
Q – 8 What is Proxy ARP in network engineering?
Ans- It is using a router to answer ARP requests. This will be done when the originating host believes that a destination is local, when in fact is lies beyond router.
Q – 9 Tell me about OSPF?
Ans- It is an Internet routing protocol that scales well, can route traffic along multiple paths, and uses knowledge of an Internet’s topology to make accurate routing decisions.
Q – 10 What is Kerberos in network engineering?
Ans- It is an authentication service developed at the Massachusetts Institute of Technology. Kerberos uses encryption to prevent intruders from discovering passwords and gaining unauthorized access to files.
Q – 11 What is the mean of multi-homed host in network engineering?
Ans- It is a host that has a multiple network interfaces and that requires multiple IP addresses is called as a Multi-homed Host.
Q – 12 What is NVT (Network Virtual Terminal) in network engineering?
Ans- It is a set of rules defining a very simple virtual terminal interaction. The NVT is used in the start of a Telnet session.
Q – 13 What is gateway-to-gateway protocol in network engineering?
Ans- It is a protocol formerly used to exchange routing information between Internet core routers.
Q – 14 What is the mean of BGP (Border Gateway Protocol)?
Ans- It is a protocol used to advertise the set of networks that can be reached with in an autonomous system. BGP enables this information to be shared with the autonomous system. This is newer than EGP (Exterior Gateway Protocol).
Q – 15 What is autonomous system in network engineering?
Ans- It is a collection of routers under the control of a single administrative authority and that uses a common Interior Gateway Protocol.
Q – 16 What is EGP (Exterior Gateway Protocol) in network engineering?
Ans- It is the protocol the routers in neighboring autonomous systems use to identify the set of networks that can be reached within or via each autonomous system.
Q – 17 What is IGP (Interior Gateway Protocol) in network engineering?
Ans- It is any routing protocol used within an autonomous system.
Q – 18 What is mail gateway in network engineering?
Ans- It is a system that performs a protocol translation between different electronic mail delivery protocols.
Q – 19 What is wide-mouth frog in network engineering?
Ans- Wide-mouth frog is the simplest known key distribution center (KDC) authentication protocol.
Q – 20 IDEA in network engineering stands for?
Ans- IDEA stands for International Data Encryption Algorithm.
Q – 21 What is packet filter in network engineering?
Ans- Packet filter is a standard router equipped with some extra functionality. The extra functionality allows every incoming or outgoing packet to be inspected. Packets meeting some criterion are forwarded normally. Those that fail the test are dropped.
Q – 22 What is traffic shaping in network engineering?
Ans- One of the main causes of congestion is that traffic is often busy. If hosts could be made to transmit at a uniform rate, congestion would be less common. Another open loop method to help manage congestion is forcing the packet to be transmitted at a more predictable rate. This is called traffic shaping.
Q – 23 What is region in network engineering?
Ans- When hierarchical routing is used, the routers are divided into what we will call regions, with each router knowing all the details about how to route packets to destinations within its own region, but knowing nothing about the internal structure of other regions.
Q – 24 Tell me about silly window syndrome?
Ans- It is a problem that can ruin TCP performance. This problem occurs when data are passed to the sending TCP entity in large blocks, but an interactive application on the receiving side reads 1 byte at a time.
Q – 25 Can you please explain the difference between Digrams and Trigrams?
Ans- The most common two letter combinations are called as digrams. e.g. th, in, er, re and an. The most common three letter combinations are called as trigrams. e.g. the, ing, and, and ion.
Q – 26 What is virtual path in network engineering?
Ans- Along any transmission path from a given source to a given destination, a group of virtual circuits can be grouped together into what is called path.
Q – 27 What is logical link control in network engineering?
Ans- One of two sub-layers of the data link layer of OSI reference model, as defined by the IEEE 802 standard. This sub-layer is responsible for maintaining the link between computers when they are sending data across the physical network connection.
Q – 28 What is virtual channel in network engineering?
Ans- Virtual channel is normally a connection from one source to one destination, although multicast connections are also permitted. The other name for virtual channel is virtual circuit.
Q – 29 Why should one care about the OSI Reference Model?
Ans- Because it provides a framework for discussing network operations and design.
Q – 30 Can you please explain the difference between routable and non- routable protocols?
Ans- Routable protocols can work with a router and can be used to build large networks. Non-Routable protocols are designed to work on small, local networks and cannot be used with a router.
Q – 31 What is MAU in network engineering?
Ans- In token Ring , hub is called Multistation Access Unit(MAU).
Q – 32 What is 5-4-3 rule in network engineering?
Ans- In a Ethernet network, between any two points on the network ,there can be no more than five network segments or four repeaters, and of those five segments only three of segments can be populated.
Q – 33 Can you please explain the difference between baseband and broadband transmission?
Ans- In a base-band transmission, the entire bandwidth of the cable is consumed by a single signal. In broadband transmission, signals are sent on multiple frequencies, allowing multiple signals to be sent simultaneously.
Q – 34 Describe the mesh network?
Ans- A network in which there are multiple network links between computers to provide multiple paths for data to travel.
Q – 35 List the important topologies for networks?
Ans-
☛ BUS topology: In this each computer is directly connected to primary network cable in a single line.
☷ Advantages: Inexpensive, easy to install, simple to understand, easy to extend.
☛ STAR topology: In this all computers are connected using a central hub.
☷ Advantages: Can be inexpensive, easy to install and reconfigure and easy to trouble shoot physical problems.
☛ RING topology: In this all computers are connected in loop.
☷ Advantages: All computers have equal access to network media, installation can be simple, and signal does not degrade as much as in other topologies because each computer regenerates it.
Q – 36 Explain the major types of networks?
Ans-
☛ Server-based network: provide centralized control of network resources and rely on server computers to provide security and network administration
☛ Peer-to-peer network: computers can act as both servers sharing resources and as clients using the resources.
Q – 37 Can you please explain the difference between TFTP and FTP application layer protocols?
Ans- The Trivial File Transfer Protocol (TFTP) allows a local host to obtain files from a remote host but does not provide reliability or security. It uses the fundamental packet delivery services offered by UDP.
The File Transfer Protocol (FTP) is the standard mechanism provided by TCP / IP for copying a file from one host to another. It uses the services offer by TCP and so is reliable and secure. It establishes two connections (virtual circuits) between the hosts, one for data transfer and another for control information.
Q – 38 List the range of addresses in the classes of internet addresses?
Ans-
Class A – 0.0.0.0 – 127.255.255.255
Class B – 128.0.0.0 – 191.255.255.255
Class C – 192.0.0.0 – 223.255.255.255
Class D – 224.0.0.0 – 239.255.255.255
Class E – 240.0.0.0 – 247.255.255.255
Q – 39 Tell me the minimum and maximum length of the header in the TCP segment and IP datagram?
Ans- The header should have a minimum length of 20 bytes and can have a maximum length of 60 bytes.
Q – 40 Can you please explain the difference between ARP and RARP?
Ans- The address resolution protocol (ARP) is used to associate the 32 bit IP address with the 48 bit physical address, used by a host or a router to find the physical address of another host on its network by sending a ARP query packet that includes the IP address of the receiver.
The reverse address resolution protocol (RARP) allows a host to discover its Internet address when it knows only its physical address.
Q – 41 Tell me what are the data units at different layers of the TCP/IP protocol suite?
Ans- The data unit created at the application layer is called a message, at the transport layer the data unit created is called either a segment or an user data-gram, at the network layer the data unit created is called the data-gram, at the data link layer the data-gram is encapsulated in to a frame and finally transmitted as signals along the transmission media.
Q – 42 Explain ICMP (Internet Control Message Protocol)?
Ans- ICMP is Internet Control Message Protocol, a network layer protocol of the TCP/IP suite used by hosts and gateways to send notification of datagram problems back to the sender. It uses the echo test / reply to test whether a destination is reachable and responding. It also handles both control and error messages.
Q – 43 What are Gateways in network engineering?
Ans- They relay packets among networks that have different protocols (e.g. between a LAN and a WAN). They accept a packet formatted for one protocol and convert it to a packet formatted for another protocol before forwarding it. They operate in all seven layers of the OSI model.
Q – 44 What are Routers in network engineering?
Ans- They relay packets among multiple interconnected networks (i.e. LANs of different type). They operate in the physical, data link and network layers. They contain software that enable them to determine which of the several possible paths is the best for a particular transmission.
Q – 45 What are Bridges in network engineering?
Ans- These operate both in the physical and data link layers of LANs of same type. They divide a larger network in to smaller segments. They contain logic that allow them to keep the traffic for each segment separate and thus are repeaters that relay a frame only the side of the segment containing the intended recipent and control congestion.
Q – 46 What is repeater in network engineering?
Ans- Also called a re-generator, it is an electronic device that operates only at physical layer. It receives the signal in the network before it becomes weak, regenerates the original bit pattern and puts the refreshed copy back in to the link.
Q – 47 Do you know what is project 802?
Ans- It is a project started by IEEE to set standards to enable intercommunication between equipment from a variety of manufacturers. It is a way for specifying functions of the physical layer, the data link layer and to some extent the network layer to allow for inter-connectivity of major LAN protocols.
It consists of the following:
☛ 802.1 is an inter-networking standard for compatibility of different LANs and MANs across protocols.
☛ 802.2 Logical link control (LLC) is the upper sub-layer of the data link layer which is non-architecture-specific, that is remains the same for all IEEE-defined LANs.
☛ Media access control (MAC) is the lower sub-layer of the data link layer that contains some distinct modules each carrying proprietary information specific to the LAN product being used. The modules are Ethernet LAN (802.3), Token ring LAN (802.4), Token bus LAN (802.5).
☛ 802.6 is distributed queue dual bus (DQDB) designed to be used in MANs.
Q – 48 What is the mean of unguided media in network engineering?
Ans- This is the wireless media that transport electromagnetic waves without using a physical conductor. Signals are broadcast either through air. This is done through radio communication, satellite communication and cellular telephony.
Q – 49 What is the mean of guided media in network engineering?
Ans- These are those that provide a conduit from one device to another that include twisted-pair, coaxial cable and fiber-optic cable. A signal traveling along any of these media is directed and is contained by the physical limits of the medium. Twisted-pair and coaxial cable use metallic that accept and transport signals in the form of electrical current. Optical fiber is a glass or plastic cable that accepts and transports signals in the form of light.
Q – 50 Can you please explain the difference between bit rate and baud rate?
Ans- Bit rate is the number of bits transmitted during one second whereas baud rate refers to the number of signal units per second that are required to represent those bits.
baud rate = (bit rate / N)
where N is no-of-bits represented by each signal shift.
Q – 51 What is MAC (Media Access Control) address?
Ans- The address for a device as it is identified at the Media Access Control (MAC) layer in the network architecture. MAC address is usually stored in ROM on the network adapter card and is unique.
Q – 52 What is attenuation in network engineering?
Ans- The degeneration of a signal over distance on a network cable is called attenuation.
Q – 53 What is gateway in network engineering?
Ans- A gateway operates at the upper levels of the OSI model and translates information between two completely different network architectures or data formats.
Q – 54 What is point-to-point protocol in network engineer?
Ans- A communications protocol used to connect computers to remote networking services including Internet service providers.
Q – 55 What is cladding in network engineering?
Ans- A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.
Q – 56 What is Brouter in network engineering?
Ans- Hybrid devices that combine the features of both bridges and routers.
Q – 57 What is passive topology in network engineering?
Ans- When the computers on the network simply listen and receive the signal, they are referred to as passive because they don’t amplify the signal in any way. Example for passive topology -linear bus.
Q – 58 What is the mean of RAID in Network Engineering?
Ans- A method for providing fault tolerance by using multiple hard disk drives.
Q – 59 What is NETBEUI in network engineering?
Ans- NETBEUI is NetBIOS extended user interface. A transport protocol designed by microsoft and IBM for the use on small subnets.
Q – 60 What is NETBIOS in network engineering?
Ans- NETBIOS is a programming interface that allows I/O requests to be sent to and received from a remote computer and it hides the networking hardware from applications.
Q – 61 What is redirector in network engineering?
Ans- Redirector is software that intercepts file or prints I/O requests and translates them into network requests. This comes under presentation layer.
Q – 62 What is beaconing in network engineering?
Ans- The process that allows a network to self-repair networks problems. The stations on the network notify the other stations on the ring when they are not receiving the transmissions. Beaconing is used in Token ring and FDDI networks.
Q – 63 What is the mean of “triple X” in Networks?
Ans- The function of PAD (Packet Assembler Dis-assembler) is described in a document known as X.3. The standard protocol has been defined between the terminal and the PAD, called X.28; another standard protocol exists between hte PAD and the network, called X.29. Together, these three recommendations are often called “triple X”.
Q – 64 What is SAP in network engineering?
Ans- Series of interface points that allow other computers to communicate with the other layers of network protocol stack.
Q – 65 Tell me the possible ways of data exchange?
Ans-
☛ Simplex
☛ Half-duplex
☛ Full-duplex.
Q – 66 What is subnet in network engineering?
Ans- A generic term for section of a large networks usually separated by a bridge or router.
Q – 67 Can you please explain the difference between communication and transmission?
Ans- Transmission is a physical movement of information and concern issues like bit polarity, synchronization, clock etc.
Communication means the meaning full exchange of information between two communication media.
Q – 68 Tell me the two types of transmission technology available?
Ans-
☛ Broadcast and
☛ point-to-point
Q – 69 What is piggy backing in network engineering?
Ans- A technique called piggybacking is used to improve the efficiency of the bidirectional protocols. When a frame is carrying data from A to B, it can also carry control information about arrived (or lost) frames from B; when a frame is carrying data from B to A, it can also carry control information about the arrived (or lost) frames from A.
Q – 70 What is pipelining in network engineering?
Ans- In networking and in other areas, a task is often begun before the previous task has ended. This is known as pipe-lining.