HOME > PROGRAMS > CCNA Interview questions -Networking Basics

CCNA Interview questions -Networking Basics

Define Network?

Network in general terms means a group of devices, connected with the help of some media in order to share some resources from a source to a destination and networking is a process of sharing the resources.

Differentiate User Mode from Privileged Mode.

Commands applied on user mode cannot effect the router while some commands of privilege mode can change the configurations. In user mode, no configuration can be made. We can only check the reachability and some basic commands in that mode. While in Privilege mode we can save, delete and modify the configuration files.

What is a Link?

Link is a physical or a logical component of a network to interconnect nodes or devices.

What is Bandwidth?

Ans – Bandwidth is the capacity of a wired or wireless network communications link to transmit the maximum amount of data from one point to another over a computer network or internet connection in a given amount of time — usually one second.

What is the difference between broadcast domain and collision domain ?

Broadcast domain is a domain where if a broadcast frame is forwarded, every devices pays attention and receives the data.

While in Collision domain, chances of data collision is maximum. Like in Hub , if two or more send traffic at the same time, data will collide in between and none of the devices will receive the data.

Explain Flooding?

Ans- In a network, flooding is the forwarding by a router of a packet from any node to every other node attached to the router except the node from which the packet arrived. Flooding is a way to distribute routing information updates quickly to every node in a large network.

What is Telnet?

A network protocol that allows a user on one computer to log onto another computer .it uses TCP Port number 23

What is Sub Interface?

A sub interface is a virtual interface created by dividing one physical interface into multiple logical interfaces. A sub-interface in a Cisco Router uses the parent physical interface for sending and receiving data.

What is BootP?

Ans – The Bootstrap Protocol (BOOTP) is a computer networking protocol used in Internet Protocol networks to automatically assign an IP address to network devices from a configuration server.

What is a Window in networking terms?

Ans – A Window refers to the number of segments that is allowed to be sent from source to destination before an acknowledgement is sent back.

What is a node?

Node is a connection point on network for data transmission. It can be a computer or printer or any type of device that is capable of sending and receiving the data over the network.

What is a gateway?

Gateway is a node of a network which can be used as an entrance for other network. It is a piece of hardware and different from default gateway.

What is WAN?

Ans – A wide area network (WAN) is a network that exists over a large-scale geographical area. A WAN connects different smaller networks, including local area networks (LANs) and metro area networks (MANs). This ensures that computers and users in one location can communicate with computers and users in other locations..

How does cut-through LAN switching work?

In Cut-Through LAN switching, as soon as the router receives the data frame, it will immediately send it out again and forward it to the next network segment after reading the destination address.

What is point-point link?

A connection between two nodes of the network is referred as point to point network and that link which connects both nodes is point to point link. Point-to-point protocol is widely used for the heavier and faster connections necessary for broadband communications.

What is VPN?

Ans- A virtual private network (VPN) extends a private network across a public network, and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network. Applications running across the VPN may Therefore benefit from the functionality, security, and management of the private network.

what is latency ?

Ans- Network latency is an expression of how much time it takes for a packet of data to get from one designated point to another. In some environments latency is measured by sending a packet that is returned to the sender; the round-trip time is considered the latency.

What’s the benefit of subnetting?

With the help of subnetting we can break a large network into smaller networks and assign IP addresses to those networks without changing our major network. It helps in utilizing our IP addresses more efficiently.

What is BGP (Border Gateway Protocol)?

BGP is an exterior gateway protocol used to connect two or more different autonomous systems. It is widely being used to route the traffic of Internet. It can also work for internal AS but we have better protocols for internal connectivity. It has Administrative distance of 20 for external routes and 200 for internal routes.

Explain clustering support?

Ans -In a computer system, a cluster is a group of servers and other resources that act like a single system and enable high availability and, in some cases, load balancing and parallel processing.

What is DoS?

Ans – DOS (Disk Operating System) is an operating system that runs from a hard disk drive. The term can also refer to a particular family of disk operating systems, most commonly MSDOS (Microsoft Disk Operating System).

What is NOS?

Ans- A network operating system (NOS) is a computer operating system system that is designed primarily to support workstation, personal computer, and, in some instances, older terminal that are connected on a local area network (LAN).

What is Gateway-to-Gateway protocol?

Gateway-to-Gateway protocol is now obsolete. This was being used for routing datagrams between internet gateways. It uses Minimum hop Algorithm.

What are firewalls?

Ans- A firewall is a network security device that monitors incoming and outgoing network traffic and decides whether to allow or block specific traffic based on a defined set of security rules. Firewalls have been a first line of defense in network security for over 25 years. They establish a barrier between secured and controlled internal networks that can be trusted and untrusted outside networks, such as the Internet. A firewall can be hardware, software, or both.

What are some drawbacks of implementing a ring topology?

Ans- In case one workstation on the network suffers a malfunction, it can bring down the entire network. Another drawback is that when there are adjustments and reconfigurations needed to be performed on a particular part of the network, the entire network has to be temporarily brought down as well.

What is a Multi-homed Host?

Multi-homed host is defined as a node connected with more than one networks. Like a PC can be connected with both Home network and a VPN. These kind of hosts can be assigned with multiple addresses, one for each network. 

What is OSPF?

OSPF stands for Open Shortest Path First. It is a link state routing protocol that can connect a large number of networks without having any limitation to number of hops. It uses Dijkstra Algorithm and considers Cost as its’ metric. It has AD of 110 and uses the concepts of Areas, Router-id, Process-id and Virtual link for connectivity.

What is Routing?

Routing is a process of exchanging route information form one router to another. Without routing it is impossible to connect two or more networks located at different or same geographical areas.

What is a Protocol?

Protocol is set of rules on which a sender and a receiver agrees to transmit the data. Protocols are responsible for data communication in between networks

What is a Frame Relay?

Ans- Frame relay is a packet-switching telecommunication service designed for cost-efficient data transmission for intermittent traffic between local area networks (LANs) and between endpoints

in wide area networks (WANs).

What is HDLC?

Ans- A high-level data link control (HDLC) is a protocol that is a bit-oriented synchronous data link layer. HDLC ensures the error-free transmission of data to the proper destinations and controls the data transmission speed. HDLCs can provide both connection-oriented and connectionless services.

What is DLCI?

Ans- A data link connection identifier (DLCI) is a Frame Relay 10-bit-wide link-local virtual circuit identifier used to assign frames to a specific PVC or SVC. Frame Relay networks use DLCIs to statistically multiplex frames. DLCIs are preloaded into each switch and act as road signs to the traveling frames.

Explain difference between Router,Switch and Hub ?

Ans- Following are the differences in Hub, Routers and Switches,

Hubs

  • Hubs operate at Layer 1 of OSI model.
  • Hubs cannot process layer-2 or layer-3 traffic. Layer-2 deals with hardware addresses and layer-3 deals with logical (IP) addresses. So, hubs cannot process information based on MAC or IP addresses.
  • Hubs cannot even process data based on whether it is a unicast, broadcast or multi-cast data.
  • Hub transfers data to every port excluding the port from where data was generated.
  • Hubs work only in half duplex mode.
  • Collisions can happen.
  • In case of a collision, a hub rejects data from all the devices and signals them to send data again. Usually devices follow a random timer after which data is sent again to hub.
  • Maximum 2-12 number of ports can be found on Hubs.

Switches

  • Switches are network devices that operate on layer-2 of OSI model. Some switches operate at higher level too.
  • Switches are also known as intelligent hubs.
  • Switches operate on hardware addresses (MAC) to transfer data across devices connected to them.
  • It performs broadcast at first, after that Unicast.
  • Major difference between Bridge and Switch being that a switch forwards data at wire speed as it uses special hardware circuits known as ASICs.
  • Switches support full duplex data transfer communication.
  • As layer 2 protocols headers have no information about network of data packet so switches cannot forward data based or networks and that is the reason switches cannot be used with large networks that are divided in sub networks.
  • Switches can avoid loops through the use of spanning tree protocol.
  • Switches can have 24-48 ports and can be practically unlimited ports because they don’t divide speed unlike Hubs.

Routers

  • Routers are the network devices that operate at Layer-3 of OSI model.
  • As layer-3 protocols have access to logical address (IP addresses) so routers have the capability to forward data across networks.
  • Routers are far more feature rich as compared to switches.
  • Routers maintain routing table for data forwarding.
  • Routers have lesser port densities as compared to switches.
  • Routers are usually used as a forwarding network elements in Wide Area Networks. 

What is Checksum?

A checksum is an error-detection method in a the transmitter computes a numerical value according to the number of set or unset bits in a message and sends it along with each message frame. At the receiver end, the same checksum function (formula) is applied to the message frame to retrieve the numerical value. If the received checksum value matches the sent value, the transmission is considered to be successful and error-free. A checksum may also be known as a hash sum

What is Redundancy ?

Redundancy is a method of insuring network availability in case of network or path failure. Generally referred as backup paths in a networks.

What is multicast routing?

Ans- Multicast IP Routing protocols are used to distribute data (for example, audio/video streaming broadcasts) to multiple recipients. Using multicast, a source can send a single copy of data to a single multicast address, which is then distributed to an entire group of recipients.

What are the criteria necessary for an effective and efficient network?

Ans-. A. Performance

  • It can be measured in many ways, including transmit time and response time.

Reliability

  • It is measured by frequency of failure, the time it takes a link to recover from a failure, and
  • the network’s robustness.

Security

  • Security issues include protecting data from unauthorized access and virus

What is the key advantage of using switches?

Ans- Switch doesn’t broadcast on all the ports. They can be managed and vlans cab be created. They are fast, can store MAC addresses. They also don’t divide the speed on each ports.

The main advantage of using switches is that each switch port has its own collision domain which removes the occurance of collision of frames. It forwards the packets based on the destination address, thereby eleminating unnecessary forwarding of packets to all ports as in hubs.

When does network congestion occur?

Ans-Congestion occurs when bandwidth is insufficient and network data traffic exceeds capacity.

Does a bridge divide a network into smaller segments?

Ans-No, What a bridge actually does is to take the large network and filter it, without changing the size of the network.

What is the difference between OSI and TCP/IP Model?

OSI(Open System Interconnection)

TCP/IP (Transmission Control Protocol / Internet Protocol)

OSI is a generic, protocol independent standard, acting as a communication gateway between the network and end user.

TCP/IP model is based on standard protocols around which the Internet has developed. It is a communication protocol, which allows connection of hosts over a network.

OSI model has a separate Presentation layer and Session layer.

TCP/IP does not have a separate Presentation layer or Session layer.

OSI is a reference model around which the networks are built. Generally it is used as a guidance tool.

TCP/IP model is, in a way implementation of the OSI model.

Network layer of OSI model provides both connection oriented and connectionless service.

The Network layer in TCP/IP model provides connectionless service.

Protocols are hidden in OSI model and are easily replaced as the technology changes.

In TCP/IP replacing protocol is not easy.

OSI model defines services, interfaces and protocols very clearly and makes clear distinction between them. It is protocol independent.

In TCP/IP, services, interfaces and protocols are not clearly separated. It is also protocol dependent.

It has 7 layers

It has 4 layers

What is the size of IP Address?

Ans-The size of ipv4=32bit or 4byte and ipv6=128bit or 16bytes

What is the range of class C address?

Ans-  192.0.0.0 to 223.255.255.255 Supports 254 hosts

What is POE (Power over Ethernet)?

Ans-Power over Ethernet or PoE pass electric power along with data on twisted pair Ethernet cabling. This allows a single cable to provide both data connection and electric power to devices such as wireless access points, IP cameras, and VoIP phones. It minimizes the number of wires required to install the network.

What are the advantages of Distributed Processing?

Ans-Distributed data processing is a computer-networking method in which multiple computers across different locations share computer-processing capability. This is in contrast to a single, centralized server managing and providing processing capability to all connected systems. Computers that comprise the distributed data-processing network are located at different locations but interconnected by means of wireless or satellite

Advantage: Lower cost, reliability, improved performance, reduced processing time, flexibility are the advantages of Distributed processing. 

When were OSI model developed and why its standard called 802.XX and so on?

Ans- OSI model was developed in February1980 that why these also known as802.XX Standard

80 means =1980 & 2means =February.

What is Full form of AD?

Administrative Distance or it can be Advertised Distance.

What is a peer-peer process?

Ans= Stands for “Peer to Peer.” In a P2P network, the “peers” are computer systems which are

connected to each other via the Internet. Files can be shared directly between systems on the

network without the need of a central server. In other words, each computer on a P2P network

becomes a file server as well as a client.

What is ping? Why you use ping?

Ping is a utility used to test the connectivity in the network. It stands for Packet Internet Groper.it uses ICMP [internet Control message protocol ]Protocol.

Explain difference between straight and crossover cable with examples ?

Ans- Straight cable is used to connect two different layer devices like router-switch, router-pc, and switch-pc while cross cable is used to connect two same layer devices like router-router, switch switch, and pc-pc. Color coding for both cable is different. If color coding on both ends of the cable is same, it is a straight cable, while if 1<–>3, 2<–>6 is being used, it is a cross cable for data transfer.

What is the difference between tracert and trace route?

Ans –Both Tracert and traceroute commands do similar purpose. On a router or switch you would use the command traceroute and on a pc you would use tracert .

Trace-route :

You can find this utility in LINUX/UNIX based operating Systems.

  • It rely over UDP Probe packet with destination PORT : 33434.
  • It uses random Source PORT.

Tracert :

You can find this utility in Windows based operating systems as well as Servers.

  • It rely over ICMP Type 8(Echo Packet) & Type 0(Echo Request).

What is Round Trip Time?

Round-trip time (RTT), also called round-trip delay, is the time required for a packet to travel from a specific source to a specific destination and back again.Source is the computer sending the packet and the destination is a remote computer or system that receives the packet and retransmits it. A user can determine the RTT to and from an IP address by pinging that address

Define the terms Unicasting, Multicasting and Broadcasting and Any-casting?

Unicasting means “one on one” communication, Multicasting means “one to many” communication but there must be atleast one devices that is not receiving the traffic while broadcasting means “one to all” communication. Each device receives packets in case of broadcasting. Anycast works in IPv6 and it means to “one to nearest” communication

How many pins do serial ports of routers have?

Ans-In computer it’s known as com port and could be available in 9pin or 25 pin. On router it have 60 pins.

What are the differences between static ip addressing and dynamic ip addressing?

Ans- When a device is assigned a static IP address, the address does not change. Most devices use dynamic IP addresses, which are assigned by the network when they connect and change over time.

Difference between CSMA/CD and CSMA/CA ?

CSMA/CD is responsible for detecting collision in wired media mainly, while CSMA/CA works on wireless media to completely avoid collision because detecting collision in wireless media is a bit hard.

What is DHCP scope?

Ans- A DHCP scope is a valid range of IP addresses that are available for assignment or lease to

client computers on a particular subnet. In a DHCP server, a scope is configured to determine the

address pool of IPs that the server can provide to DHCP clients. Scopes determine which IP

addresses are provided to the clients.

What are the different memories used in a CISCO router?

ROM

ROM is read-only memory available on a router’s processor board. The initial bootstrap software that runs on a Cisco router is usually stored in ROM. ROM also maintains instructions for Power-on Self Test (POST) diagnostics.

Flash Memory

Flash memory is an Electronically Erasable and Re-Programmable memory chip. The Flash memory contains the full Operating System Image (IOS, Internetwork Operating System).Flash memory retains content when router is powered down or restarted.

RAM

RAM is very fast memory that loses its information when the router is shutdown or restarted. On a router, RAM is used to hold running Cisco IOS Operating System, IOS system tables and buffers RAM is also used to store routing tables,RAM Provides temporary memory for the router configuration file of the router while the router is powered on.

RAM Stores running Cisco IOS Operating System, Active program and operating system instructions, the Running Configuration File, ARP (Address Resolution Protocol) cache, routing tables and buffered IP Packets.

NVRAM (Non-volatile Random Access Memory)

NVRAM is used to store the Startup Configuration File. This is the configuration file that IOS reads when the router boots up. It is extremely fast memory and retains its content when the router is restarted.

What are the different types of passwords used in securing a CISCO router?

Enable password, Secret Password, Line passwords (VTY, Console and Aux) are the passwords used in Router.

What are the different types of passwords used in securing a CISCO router?

Ans- Depending on Connection (Device) :

  • Enable password
  • Console password
  • VTY password
  • AUX password

What is the use of “Service Password Encryption” ?

Service Password Encryption command encrypts plain text password into type 7 password. These are not very much secure and can be easily decrypted.

Briefly explain the conversion steps in data encapsulation.?

Process of adding header and trailer information in data is called Data Encapsulation. Whenever a layer passes the data to next layer it adds some extra information in data. This is called header. Next layer then processes the data and adds its own header. This process continues until data is place on physical media. This process is called Encapsulation. Removing header and trailer information from the data is called Data Decapsulation.

Step

Action

Layers Involved

Keyword

Step 1

Alphanumeric input from user converted into Data

Application/Presentation/Session

DATA

Step 2

Data converted into segments

Transport

SEGMENTS

Step 3

Segments converted into Packets or Datagrams and Network Header is added

Network

PACKETS

Step 4

Packets or Datagrams are built into Frames

Data Link

FRAMES

Step 5

Frames are converted into bits( 1s and 0s) for transmission

Physical

BITS

In configuring a router, what command must be used if you want to delete the configuration data that is stored in the NVRAM?

Ans- Erase startup-config is the command to delete preconfigured files on the router.

IEEE standard for wireless networking?

Ans- 802.11

What is the range of class A address?

Ans- From 0.0.0.0 – 127.255.255.255, but we cannot use 0 and 127, so actual range is from 1 to 127

What is the range of class B address?

Ans- From 128.0.0.0 – 191.255.255.255

Differentiate Logical Topology from Physical Topology?

Physical topology represents the physical structure i.e cabling of the network while logical topology deals with the data flow in the network.

what is AS (Autonomous System) ?

A group of devices under a single administration is called an AS. AS Number is assigned by IANA (The Internet Assigned Numbers Authority)

What is the difference between Private IP and Public IP ?

Public IP addresses are for global routing over internet. They are allocated to the websites and companies to access the internet. They are unique worldwide if connected to Internet. Private IP addresses are for local use and are not routable over internet. They can be same in different organization.

Explain different cable types ?

Straight, Cross, Serial, Console are some cable types used in networking. Serial cable is used to connect a router to another router. Console cable is used to access the router or switches from a PC.

How does RIP differ from EIGRP?

The major difference between both is that EIGRP is Cisco propriety and RIP is open standard

Some internal differences between them are:

  •    AD value of Rip is 120 and AD value for EIGRP is 90 internal / 170 external.
  •       RIP uses Bellmen ford algorithm to calculate the path while Eigrp use Dual method to calculate the routes paths
  •       Maximum hop count for RIP is 15 that is after 15 counts the packet is dropped while that of EIGRP is 100 by default and upto 255 by configuration.
  •       RIP(ver 1) is classfull protocol where as EIGRP is classless protocol
  •       In RIP full routing table exchanged, but in EIGRP missing routes are exchanged
  •       For RIP protocol, hello timers every 30 seconds but in EIGRP hello timer every 5 seconds
  •       RIP v1 sends updates as broadcast while EIGRP send updates as Multicast
  •       EIGRP uses an Autonomous number to determine which domain it belongs to which is not the case with RIP protocols.
  •       RIP is mostly used for smaller networks which EIGRP is used for larger networks.
  •       RIP is a distance vector routing protocol while EIGRP is an hybrid routing protocol.
  •       RIP sends full update whenever network change occurs whereas EIGRP sends triggered updates

Differentiate User Mode from Privileged Mode

Commands applied on user mode cannot effect the router while some commands of privilege mode can change the configurations. In user mode, no configuration can be made. We can only check the reachability and some basic commands in that mode. While in Privilege mode we can save, delete and modify the configuration files.

What is 100BaseFX?

100BASE-FX is a version of Fast Ethernet over optical fiber.

Differentiate full-duplex from half-duplex ?

In full duplex, user can send and receive data at the same time while in half duplex user can either receive or send the data at a time.

What does the show protocol display?

The show protocols command shows the global and interface-specific status of any configured Level 3 protocol.

OSI Model Interview Questions & Answers

List the layers of OSI?

From top to bottom, OSI layers are-

Application, Presentation, Session, Transport, Network, Data Link and Physical.

What are the responsibilities of Data Link Layer?

Framing, Error detection, CRC and Physical Addressing is the task of DLL.

What are the responsibilities of Network Layer?

Routing, IP Addressing and Path determination are the main responsibilities of Network Layer.

What are the responsibilities of Transport Layer?

Transport Layer has a lot of function. Most important being,

  • Multiplexing and De-Multiplexing
  • Segmentation and Re-assembly
  • Flow Control
  • Error Correction
  • Connection Establishment
  • Sequencing
  • Acknowledgement
  • 3 way Handshake

Routers work at which OSI layer?

Network Layer

Switches work at which OSI layer?

Layer 2 and Some Switches can operate at Layer 3 and above

What is a Window in networking terms?

Window is the amount of segments sent by TCP between two acknowledgements.

What is the role of the LLC sublayer in datalink layer?

Logical Link Control provides error detection, using Ethernet trailer field frame check sequence (FCS).

What is the function of the Application Layer in networking?

Application Layer is responsible for providing a user interface in between user and Network with the help of applications like web browsers.

What is the difference between TCP and UDP?

Following are differences in TCP and UDP,

  • TCP stands for “Transmission Control Protocol” UDP stands for “User datagram Protocol”.
  • TCP is connection oriented protocol while UDP is connectionless protocol.
  • TCP is more reliable than UDP.
  • UDP is faster for data sending than TCP.
  • UDP makes error checking but no reporting but TCP checks for errors and performs reporting.
  • TCP provides guaranteed Delivery of Data but UDP has no guarantee.
  • Header size of TCP is 20 bytes while that of UDP is 8 bytes.
  • TCP has acknowledgement segments but UDP has no acknowledgement.
  • TCP is used for application that require high reliability but less time critical whereas UDP is used for application that are time sensitive but require less reliability.

What is the port no of DNS and Telnet?

DNS = 53, Telnet = 23

Which service use both TCP and UDP ?

DNS uses both TCP and UDP

What is the port no of SMTP and POP3?

POP3 = 110; SMTP = 25

In which layer term “Frames” is used ?

Frames are PDU of Data Link Layer

In which layer term “Packets” is used ?

Packets are PDU of Network Layer

In which layer term “Segments” is used ?

Segments are used at Transport Layer

Give some example for protocols work at Application layer ?

Application Layer Protocols are  HTTP, HTTPs, Telnet, SSH, DNS, FTP, TFTP, DHCP, RIP

What is CRC? Which layer CRC works ?

Cyclic Redundancy Check is used to detect the errors in network. It works at Data Link Layer (LLC Sub Layer).

What is the purpose of the Data Link?

Data Link Layer is responsible for Framing, Error Detection and Physical Addressing

Which one is reliable – TCP or UDP ?

TCP is reliable.

What is the port number of ftp (data) and ftp?

FTP port number 20 (Data); 21 for Control

Which layer provides logical addressing that routers will use for path determination?

Network Layer

Which layer specifies voltage, wire speed, and pinout cables and moves bits between devices ?

Physical

Which layer combines bits into bytes and bytes into frames, uses MAC addressing, and provide error detection ?

Data Link Layer

Which layer is responsible for keeping the data from different applications separate on the network ?

Session layer.

Which layer segments and resembles data into a data stream ?

Transport layer.

Which layer provides the physical transmission sof the data and handless error notification, network topology, and flow control ?

Data Link Layer

Which Layer manages device addressing, tracks the location of devices on the network, and determine the best way to move data ?

Network layer.

How Data breaks down on each layer from top to bottom ?

Encapsulation occurs in following format

MAC address works on which layer ? What are the differences of MAC sublayer and LLC sublayer?

MAC works at DATA LINK LAYER. Media Access Control provides physical addressing while Logical Link Control provides error detection, using Ethernet trailer field frame check sequence (FCS). It is 4 bytes field. When a sending device sends a data it put the data in a mathematical algorithm and it gets a product, sending device puts the product in FCS. When a receiving device receive a data it also put the data in same mathematical algorithm and get a product. If both products are same, Frame is accepted or else discarded.

Which layer is responsible for converting data packets from the Data Link layer into electrical signals ?

Physical Layer

At which layer is routing implemented, enabling connections and path selection between two end systems. ?

Network Layer

Which layer defines how data is formatted, presented, encoded,and converted for use on the network ?

Presentation Layer

Which layer is responsible for creating, managing and terminating sessions between applications ?

Session Layer

DNS uses which protocol? Why?

DNS uses both TCP and UDP. It is necessary to maintain a consistent DNS database between DNS Servers This is achieved by the TCP protocol. A client computer will always send a DNS Query using UDP Protocol over Port 53. If a client computer does not get response from a DNS Server, it must re-transmit the DNS Query using the TCP after 3-5 seconds of interval.

Which layer is closer to the user?

From sender point of view, Application Layer is closest and from Receiver point of view Pgysical Layer is closest.

Differentiate between forward lookup and reverse lookup in DNS?

  • Forward Lookup: Name to IP resolution
  • Reverse Lookup: IP to Name resolution;

What is IPSec?

IPSec provides data security at the IP Packet Level.

What is the way to establish a TCP connection?

TCP Connection is established using three-way Handshake.

What is the difference between flow control and error control?

Error Controls the process of detecting and correcting both the bit and packet level error. While flow control is a mechanism to ensure the efficient delivery of Data. Flow control is agreeing on the minimum amount of data that a receiver can handle at a time.

Enquire Now