Top CCNA Interview Questions and Answers

1 .

The CCNA (Cisco Certified Network Associate) is an entry-level networking certification that can prepare you for networking roles. A CCNA certification certifies a technician's ability to install, set up, configure, troubleshoot and operate a medium-sized routed and switched computer network. This also includes implementing and verifying connections to a wide area network (WAN).

2 .

What about Cisco Certified Network Associate (CCNA)?

A CCNA three-year certification is obtained by passing Cisco Exam No.640-802 or by taking two other exams with passing scores : ICND1 No.640-822 and ICND2 No.640-816.

Subjects in the curriculum include the use of frame relay, Routing Information Protocol (Version 2), Internet Protocol, Enhanced Interior Gateway Routing Protocol, virtual local area networks, access control lists and Ethernet.

All CCNA-certified individuals specialize in one of seven technology paths :

* Routing and switching

* Design

* Network security

* Service provider

* Storage networking

* Voice

* Wireless.

Colleges and universities that offer Cisco training are considered member of the Cisco Networking Academy. All specialist certifications are valid for two years. Recertification requires taking a higher-level exam or retaking the previous exam, as determined by Cisco.

3 .

What is Routing?

* Routing is a process of finding a path to transfer data from source to destination.

* Routing can be performed in a variety of networks such as circuit switched networks and computer networks.

* In packet switching networks, routing makes a decision that directs the packets from source to the destination.

* Routing makes use of a routing table, which maintains the routes of various destinations.

Examples of routers are :

Brouter : Brouter stands for "Bridge Router". It serves both as a router and bridge.

Core router : Core router is a router in the computer network that routes the data within a network, but not between the networks.

Edge router : An edge router is a router that resides at the boundary of a network.

Virtual router : A virtual router is a software-based router. The virtual router performs the packet routing functionality through a software application. A Virtual Router Redundancy protocol implements the virtual router to increase the reliability of the network.

Wireless router : A wireless router is a router that connects the local networks with another local network.

4 .

What do you mean by routers? Write some major functions.

Router is a networking device that is used to forward data packets along with a network from source to destination. The devices are specially designed to receive, analyze, and forward data packets between computer networks. It examines a destination IP address of a data packet and uses its headers and routing table to determine the best way or route for transferring the packets. There are some popular companies that develop routers like HP, Juniper, Nortel, Cisco, etc.

Functions of Routers :

* Used to create local networks of devices

* Reduce excessive traffic.
* Used to segment network traffic.
* Send and receive data on computer networks.

* Helps to connect multiple devices to the Internet.

* Allows users to configure the port as per their requirements in the network.

* Prevent network bottlenecks simply by isolating portions of a network.
* Filter unwanted interference, and carry out the process of data encapsulation and decapsulation.

5 .

What types of routes that are available in routers.

Static Route : This route is also known as a non-adaptive route. It is either directly configured on an active interface of the router or manually added to the routing table by an administrator.

Dynamic Route : This route is also known as the adaptive route. It makes automatic adjustments of the routes as per the current state of the route in the routing table and also uses routing protocols to find network destinations.

Default Route : In this, the router is configured to send all packets towards a single router, and it does not matter whether or not it belongs to a specific network. It is especially used when networks deal with a single exit point.

6 .

Name any two ports of Switches.

Access Port : An access port is a kind of connection on a switch that can be used to connect a virtual machine on VLAN unaware. This port delivers the virtual machine with connectivity by a switch that is VLAN aware without requiring it to support VLAN tagging.

Combo Port : These ports are used to connect devices to the switch. Switches are connected to a port that is called a combo port. These ports can be assigned to different combinations of devices. A device combination is a group of one or more devices used to transmit or receive data. In other words, a combo port can be a single interface with two front ends, such as an RJ45 connector and an SFP module connector (also called MiniGBIC).

7 .

What are three possible ways of data transmission in CCNA?

Simplex Mode : Simplex mode is sort of a unidirectional path within the communication is one-way. Only 1 of the 2 devices will send and the other will receive.

Half-Duplex Mode : Every station will broadcast and receive information in half-duplex mode, however, it is not at the identical time. once the device transmits data.

Full-Duplex Mode : Each station will broadcast and receive information at an identical time in full-duplex mode. Signals traveling in one direction share the link’s capability with signals traveling within the different directions in full-duplex mode :

* Either the connection or the receiver must have two physically independent transmission routes.

* On the other hand, capacitance is divided by signals moving in both directions.

8 .

Name different IPX access lists.

There are three IPX Access lists:

Standard Access list : The access list is created using the source IP address. These ACLs allow or deny the whole protocol suite. They do not differentiate between the IP traffic such as TCP, UDP, HTTPS, etc. By using digits 1-99 or 1300-1999, the router will understand it as a standard ACL and set the address as the source IP address.

Extended Access-list : It is a type of Access-list that is mainly used as it can differentiate IP traffic. the whole traffic will not be permitted or denied like in the standard access list. ACL uses both source and destination IP addresses and also port numbers to distinguish IP traffic. In this type of ACL, we can also mention which IP traffic should be allowed or denied. These use range of numbers 100-199 and 2000-2699.

Reflexive Access list : Reflexive Access-list can be defined as an access list that allows only the responses of the packets on sessions created within the network from the outside network.

9 .

What is the main objective of Data Link Layer and Transport Layer?

Data Link Layer : It is the 2nd layer of the OSI model which is generally responsible for transferring the datagram across an individual link. It is considered one of the most complicated layers and also has complex functionalities and liabilities. It also ensures that the appropriate physical protocol is assigned to the data.

Transport Layer : It is the 4th layer of the OSI model which is responsible for providing transparent transfer of data among end-users, thus providing reliable data transfer services to the top layers. Its main objective is to deliver the entire message from source to destination.

10 .

What do you mean by 100BaseFX?

100BaseFX is basically an Ethernet media standard for Ethernet over fiber optic cables, rather than twisted-pair cables. It is a version of Fast Ethernet that makes use of fiber optic cables as the main transmission medium. Here, 100 refers to 100Mbps data speed that means it carries data traffic at 100 Mbps in LAN.

11 .

What is the difference between switch and hub?

Basis of Comparison	Hub	Switch
Description	Hub is a networking device that connects the multiple devices to a single network.	A switch is a control unit that turns the flow of electricity on or off in a circuit.
Layer	Hubs are used at the physical layer.	Switches are used at the data link layer.
Transmission type	Transmission type can be unicast, broadcast or multicast.	Initially, the transmission type is broadcast and then is unicast.
Ports	Hub has 4/12 ports.	The switch has 24/48 ports.
Transmission mode	Half duplex	Half/Full duplex.
Collisions	Collisions occur commonly in a Hub.	No collisions occur in a full duplex switch.
Address used for data transmission	Hub uses MAC address for data transmission.	The switch uses a MAC address for data transmission.
Data transmission form	Electrical signal is a data transmission form of a hub.	A Frame is a data transmission form of a switch.

12 .

What is the difference between Switch and Router?

Basis of Comparison	Router	Switch
Description	It is a layer 3 device that connects the two different networks and identifies the network devices based on their IP addresses.	It is a layer 2 device and determines the network devices based on their MAC addresses.
Mode of transmission	Router transmits the data in the form of packets.	Switch transmits the data in the form of frames.
Address used	It uses an IP address for the data transmission.	It uses a MAC address to transmit the data.
Layer of OSI model	It uses Layer 3 OSI model and layer is the network layer.	It uses layer 2 OSI model and layer is the data link layer.
Table	It uses a routing table for routes to move to the destination IP.	It uses a Content address memory table for MAC addresses.
Network used	It is used for WAN and LAN networks.	It is used only for LAN networks.
Mode of transmission	Router is used in a full-duplex mode.	A switch is used in half as well as in a full-duplex mode.

13 .

What are the advantages of using Switches?

Switches are used to receive a signal and create a frame out of the bits from that signal. The signals enable you to get access and read the destination address and after reading that it forward that frame to appropriate frame. So, switches are the significant part of the transmission.

14 .

What is the OSI reference model and layers?

OSI is a reference model that tells how information and data are communicated over a network. It is a conceptual framework that understands the relationships of transmission.

Basically, there are 7 layers of the OSI model. Each layer has its own functionality in the OSI model.

* Layer 1 – Physical

* Layer 2 – Data Link Layer

* Layer 3 – Network

* Layer 4 – Transport

* Layer 5 – Session

* Layer 6 – Presentation

* Layer 7- Application

15 .

Explain the difference between a 'broadcast domain' and a 'collision domain'?

A broadcast domain is a logical division of a computer network, in which all nodes can reach others by broadcast at the data link layer.

A collision domain is a section of a network where data packets can collide with one another when being sent on a shared medium or through repeaters.

16 .

What is the difference between User Mode from Privileged Mode?

User Mode	Privileged Mode
It is used for the regular task while using a Cisco router.	Offers a lot of options, including those available in User mode.
It enables you to view system information, connect to remote devices, check the status of the router, and more.	It allows users to make configurations on the router, such as making tests and debugging.

17 .

What is CDP? Explains its functions.

CDP stands for Cisco Discovery Protocol. It is a Layer 2 proprietary protocol that runs on Cisco devices including routers and switches. This protocol collects information about directly connected neighboring devices.

It discovers the nearby devices, identifies how they are configured, and enables the systems to learn about each other by using different network-layer protocols. CDP simplifies the process of keeping an up-to-date inventory of Cisco network devices.

The CDP finds out the following information :

* iOS version running on Cisco devices

* IP addresses

* The hardware platform of devices

* Interface details

* Hostname

* VTP domain

* Duplex setting

* Native VLAN

18 .

What is the difference between TCP and UDP?

TCP (Transmission Control Protocol)	UDP (User Datagram Protocol)
It is a connection-oriented protocol.	It is a connectionless protocol.
The connection should be established before the data is transmitted over the network.	It sends the data without checking whether the system is ready to receive it or not.
Delivery of data to the destination router is guaranteed. If the connection is lost during transferring files, the server would request the lost part.	It doesn’t guarantee the delivery of data to the destination.
The message will be delivered in the order it is sent.	The message may not be delivered in the same order.
It doesn’t support broadcasting.	It supports broadcasting.
Data is read as a stream. When one packet ends, another begins.	Data Packets are transmitted individually.
Header size is 20 bytes.	Header size is 8 bytes.
It is slower than UDP	UDP is faster and more efficient than TCP
This protocol is mainly used where a secure communication process is required. Example: web browsing and e-mail.	This protocol is used when fast communication is required. Example: VoIP, video, and music streaming.

19 .

Name different memories that are used in CISCO routers.

Different memories that are used in CISCO router include :

NVRAM (Non-volatile RAM) : It is used to store startup configuration files. It also retains its content even after a device is restarted or powered down.

DRAM (Dynamic Random-Access Memory) : It is used to store configuration files that are being executed. It loses its content when a device is restarted.

ROM (Read Only Memory) : It is used to store a bootstrap program that initializes a boot process. It also runs and maintains instructions for POST diagnostics.

Flash Memory : It is used to store CISCO IOS. It can also be used to store other files such as backup configuration files.

20 .

What is the advantage of VLAN?

VLAN is a custom network which is created from one or more existing LAN's. VLAN facilitates you to create a collision domain by groups other than just physical location while in conventional LAN domains are always tied to physical location.

Advantage of VLAN :

Broadcast control : A VLAN (Virtual Area Network) removes the physical layer and, it logically separates the networks within networks creating a smaller broadcast domain. It reduces the size of the broadcast domain, therefore, improving the efficiency of the network.

Simplified administration : When a computer is moved to another location, but it stays on the same VLAN without any hardware configuration.

Security : VLANs as required and ensuring network security according to their configuration.

LAN segmentation : Virtual Area Networks are used to logically separate layer 2 switch networks. Users on different VLAN cannot communicate with each other. Therefore, it's a great way of segmentation and provides security.

Dynamic VLANs : The Dynamic VLAN's are created using the software. The VLAN Management Policy Server (VMPS) is an administrator that dynamically allocates the switch ports based on the information available such as the MAC addresses of the device.

Protocol-based VLANs : The switch that depends on the protocol based VLANs, then the traffic will be segregated by a particular protocol.

21 .

Write difference between tracert and traceroute?

Tracert : It is a Command Prompt command that is used to show various details about the path that a packet takes from the source computer to the specified destination computer. It only uses ICMP (Internet Control Message Protocol) echo requests. It can be used on a PC. This command is generally used in Windows NT-based OS.

Traceroute : As the name suggests, it is a command that is used to trace the records of the path that a packet takes from the source computer to the specified destination computer. It uses UDP (User Datagram Protocol) echo requests. Traceroute command can be used on a router or switch. This command is generally used in UNIX OS.

22 .

What are the different types of cables that are used in routing?

Three different types of cables that are used include :

* Straight cable(switch-router)

* Cross cable(PC-PC, switch-switch)

* Rollover cable(Console port to computer)

Straight cable(switch-router) :

* Straight cable is used to connect different group devices. For example Switch- Router.

* Straight cable is a kind of twisted pair cable used in a local area network to connect a computer to a network hub such as a router.

* Straight cables are used for linking different devices.

* It is an 8 wired patch cable.

* It is also used for connecting PC to the switch or router to a hub.

* The main purpose of a straight cable is to connect a host to the client.

Cross cable(PC-PC, switch-switch) :

* Cross cable is used to connect the same group devices. For example Switch-Switch.

* Cross cable is a cable used to interconnect two computers by reversing their respective pin contacts.

* Cross cable is a cross-wired cable used to connect the two computers or hosts directly.

* Cross cable is used when two similar devices are to be connected.

* Cross cable crisscross each other, and this makes the communication of two devices at the same time.

Rollover cable(Console port to computer) :

* Rollover cable is used to connect the console port to the computer.

* Rollover cable is used to connect the computer's terminal to the network's router console port.

* Rollover cable is referred to as a Cisco console cable, and it is flat and light blue in color.

* Another name of a rollover cable is Yost cable.

* Rollover cable is identified by comparing the end of the cable with another cable as rollover cables are beside each other.

* Rollover cable allows the programmer to connect to the network device and can manipulate the programming whenever required.

23 .

Explain the difference between Collision Domain and Broadcast Domain.

Broadcast Domain :

* In the Broadcast Domain, all the juncture can reach each other by broadcast at the Data Link Layer and every device is ready to receive their respective data. It can bind to the same LAN segments or the other LAN segment.

* Broadcast Domain uses a local network for broadcasting the data packets to the receiver. While broadcasting, massive data are broadcasted, hence the speed of receiving the data is less and it also takes more time to receive the data of their address.

Collision Domain :

* In the Collision Domain, data collision occurs more due to the sending of more frames simultaneously.

* If more than two frames are sent simultaneously then the data will collide with each other in between and the information gets lost. Hence, the devices will not accept the data and due to this, the communication between the sender and receiver side will collide.

* Thus, the sender has to send the data again and like this, it will take more time to receive the data at the receiver’s side.

24 .

What do you mean by DLCI?

DLCI (Data Link Connection Identifier) is the quantity of a personal or switched virtual circuit in a frame relay network, situated within the frame header, the DLCI field identifies that logical circuit the data travels over, and each DLCI includes a committed information rate (CIR) associated with it.

25 .

What are the three sources of signal degradation on a data link?

The three sources of signal degradation on a data link are attenuation, interference, and distortion. Attenuation is a function of the resistance of the medium. Interference is a function of noise entering the medium. Distortion is a function of the reactive characteristics of the medium, which react differently to different frequency components of the signal.

26 .

What is HDLC?

* HDLC stands for High-Level Data Link Control protocol. It is the property protocol of Cisco which is the default encapsulation operated with Cisco routers.
* HDLC is a bit-oriented protocol that supports both half and full duplex communication.

* HDLC adds the information in a data frame that allows the devices to control the data flow.

* HDLC offers flexibility, adaptability, reliability, and efficiency of operation for synchronous data communication.

* It supports both point-to-point and point-to-multipoint communication.

* It supports synchronous as well as asynchronous communication.

* It provides full data transparency, i.e., the output delivered has the same bit sequence as the input without any restriction.

27 .

What are the advantages of LAN switching?

LAN switching : LAN switching enables the multiple users to communicate with each other directly. LAN switching provides the collision-free network and high-speed networking.

The main advantages of LAN switching :

Increased network scalability : LAN switching can handle the increasing amount of work. Therefore, we can say that when the business grows, the network can expand easily.

No single point of failure : LAN switching provides the proper network designing. Therefore, there are fewer chances of network failure.

Improved bandwidth performance : We require higher bandwidth performance when users operate multimedia applications or some database interactions.

Multiple simultaneous connections : LAN switching allows multiple simultaneous connections, i.e., it can transfer the multiple data at the same time. This cannot be possible in the case of a hub-based network.

Allows full duplex data transmission : LAN switching allows full duplex data transmission, i.e., the data can be transferred in a bidirectional line at the same time.

Reduced congestion and transmission delay : LAN switching improves the performance of a network as a segmented network consists of fewer hosts per subnetwork and thus, minimizing the local traffic.

28 .

What are the different types of CCNA Networks?

These are the two major types of networks:

1. Peer-to-Peer Network :

* In a peer-to-peer network, 'peers' are the computers which are connected to each other through an internet connection.

* The computer systems on the network without the need for any computer server.

* Therefore, the computer in P2P is a "computer server" as well as a "client".

* Requirements for a computer to have a peer-to-peer network are the internet connection and P2P software.

* Some of the common P2P software peers include Kazaa, Limewire, BearShare, Morpheus, and Acquisition.

* Once we are connected to the P2P network, then we able to search the files on other people's computer.

Peer-to-Peer Network

Types of a peer-to-peer network :

Pure P2P : In P2P, peers act as a client and server. There is no central server and central router present in the pure P2P.

Hybrid P2P : Hybrid P2P has a central server that stores the information and responds to the request for that information. Peers are used for hosting the information as a central server does not store the files. Nasper is an example of Hybrid P2P.

Mixed P2P : Mixed P2P is a combination of pure P2P and Hybrid P2P.

2. Server-based Network :

* In a server-based network, server act as a base for the network known as a central server.

* The central server handles multiple tasks such as authenticating users, storing files, managing printers, and running applications such as database and email programs.
Server Based Network

* In case of a server-based network, security is centralized in the system which allows the user to have one login id and password to log on to any computer system.

* Server-based networks are more complex and costly and often requires full- time services for administration.

* In server-based networks, the majority of traffic occurs between the servers.

29 .

Define Frame relay?

Frame relay is a technology that provides fast and reliable data transmission in Internet networks. It is a standards-based networking technology that provides a path for data packets from one point on the network to another.

30 .

What do you mean by User mode and Privileged mode?

User Mode : User mode is generally used to view the configurations of the routers. It allows us to view basic system information, check router status, connect to remote devices, etc. User mode is mostly used to perform regular tasks on the router when we are using a Cisco router.

Privileged Mode : Privileged mode is generally used to view all the configurations on the router. It allows you to change configurations that are less important. Privileged mode is mostly used to perform high-level tasks on the routers such as making configurations and debugging.

31 .

What do you mean by MTU?

MTU (Maximum Transmission Unit) is considered the largest size frame or packet that a network-connected device will accept. Its default size is 1500 bytes which is the largest Ethernet standard unit. TCP (Transmission Control Protocol) generally uses MTU to determine the maximum size of each packet in any transmission.

32 .

Explain the terms Unicast, Multicast, Broadcast.

In all these three terms, ‘cast’ refers to the transmission of data packets from the client to the recipient over the communication channel.

1. Unicast (One-to-One) :

It is a one-to-one communication technique, in which data communication takes place between a single sender and a single recipient in the network.

Examples of Unicast are :

* Browsing a website. The webserver is the sender and your computer is the receiver.

* Downloading a file from an FTP Server. FTP Server is the sender and your computer is the receiver.

2. Broadcast (One-to-All) :

It specifies one to all communication. Data communication takes place among all the devices available in the network. The data is sent from one computer once and a copy of that data will be forwarded to all the connected devices. Two types of Broadcast are: Limited Broadcasting and Direct Broadcasting.

Example of Broadcast :

* Television networks for video and audio distribution.

3. Multicast (One-to-Many) :

Multicast specifies one to group or one to many communication. In Multicast, one or more senders and one or more recipients participate in data transfer. IP multicast traffic is sent to a group and only members of that group receive the Multicast traffic. It uses IGMP (Internet Group Management Protocol) protocol to identify the group.

Examples of Multicast :

* Sending an e-mail to a particular mailing group.

CCNA Cast

33 .

What are the different classes of IP addresses? Mention their ranges.

There are five classes of IP address :

Class	Range
A	1-126
B	127-191
C	192-223
D	224-239
E	240-254

34 .

What is the function of an LLC sublayer?

LLC (Logical Link Control) is basically the upper sublayer of the data link layer and acts as an interface between the network layer and MAC sublayer of the data link layer of the OSI model. This sublayer provides the logic for data link as it controls the synchronization, flow control, multiplexing, and also error checking functions of the data link layer. It simply provides optional services to an application developer.

35 .

What is EIGRP? Mention some metrics of the EIGRP Protocol.

EIGRP (Enhanced Interior Gateway Routing Protocol) is referred to as Cisco's IGP (Interior Gateway Protocol) that is used on a computer network especially for automating routing decisions and configurations. This protocol is suited for different topologies and media. It is mostly used on a router to share routes with other routers within the same autonomous system.

EIGRP Protocol generally includes the following metrics :

* Bandwidth

* Load

* Delay

* Reliability

* MTU

* Maximum Transmission Unit

36 .

What is a BootP?

BootP (Bootstrap Protocol or Boot Program) is defined as a computer networking protocol that is being used by a client for obtaining an IP address of a server PC. In a network, BootP is generally used for booting diskless workstations. These diskless workstations use BootP to get their own IP address as well as the server’s IP address. It was originally designed to replace RARP (Reverse Address Resolution Protocol), also known as RFC 903.

37 .

What is the difference between static IP addressing and dynamic IP addressing?

Basis of Comparison	Static IP address	Dynamic IP address
Description	Static IP address is a fixed number assigned to the computer.	The dynamic IP address is a temporary number assigned to the computer.
Provided By	Static IP address is provided by ISP(Internet Service Provider).	The dynamic IP address is provided by DHCP(Dynamic Host Configuration Protocol).
Change requirement	It is static means that IP address does not change.	It is non-static means that IP address changes whenever the user connects to a network.
Security	It is not secure as IP address is constant.	It is secure because each time IP address changes.
Cost	It is costlier than Dynamic IP address.	It is cheaper than the Static IP address.
Device tracking	Static IP address is trackable as IP address is constant.	The dynamic IP address is untraceable as IP address is always changing.

38 .

What is the difference between CSMA/CD and CSMA/CA?

CSMA/CD stands for Carrier Sense Multiple Access with Collision Detection. It is a media access control method used in local area networking using early Ethernet technology to overcome the occurred collision.

CSMA/CA stands for Carrier Sense Multiple Access with Collision Avoidance. It is used in the wireless network to avoid the collision.

CSMA/CD	CSMA/CA
Full form of CSMA/CD is carrier sense multiple access with collision detection.	Full form of CSMA/CA is carrier sense multiple access with carrier avoidance.
CSMA/CD detects the collision, and once the collision is detected, then it stops continuing the data transmission.	CSMA/CA does not deal with the recovery of the collision.
Wired installation is used in a CSMA/CD to detect the collision.	Wireless installation is used in a CSMA/CA as it avoids the collision. Therefore, it does not need a wired network.
An 802.3 Ethernet network uses CSMA/CD.	An 802.11 ethernet network uses CSMA/CA.
CSMA/CD takes effect after the occurrence of a collision.	CSMA/CA takes effect before the occurrence of a collision.

39 .

What is network congestion? When network congestion happens?

Network congestion is a situation that occurs when a network node is overloaded with data or traffic and can cause a common problem for admins. It usually occurs when the network is carrying or exchanging more data than the network devices like routers and switches can accommodate. It is a result of an internet route becoming too full when many users try using the same bandwidth. This condition is true in big networks that do not resort to network segmentation

40 .

What are types of passwords that can be used in CISCO routers?

Different types of passwords that can be used in CISCO routers include :

Enabled : This is a global command that disables privileged execution mode. The password is not encrypted. To change it, one can use "enable password password"

Enable Secret : In place of an enable password, this secret password is used. To change it, one can use "enable secret password".

AUX (Auxiliary) : Passwords for auxiliary ports can be set using an auxiliary password. Through a modem, a router can be accessed via this port.

Console : Console port passwords are set using the console password.

VTY (Virtual Terminal) : For Telnet sessions into the router, you will need the virtual terminal password. Passwords can be changed at any time. You can set it up when you configure the router from the console.

41 .

Write difference between public IP and private IP?

Public IP	Private IP
It is used on public networks.	It is mostly used within a private network or LAN to connect securely with other devices within the same network.
It is usually assigned by a Service provider or IANA.	It is usually assigned by a LAN administrator.
It is generally used to communicate outside the network.	It is generally used to communicate within the same network.
It can be known by searching “what is my IP” on google.	It can be known by typing “ipconfig” on the command prompt.
Its scope is global.	Its scope is local to the present network.
These come with a cost and are controlled by ISP.	These are free of cost and are used to load network OS.
It is routable and therefore, communication among different users is possible.	It is not routable and therefore, communication among different users is not possible.
It can be any number not included in the reserved private IP address range. Example: 202.60.23.1	Address ranges to be used by private networks are: Class A: 10.0.0.0 - 10.255.255.255 Class B: 172.16.0.0 - 172.31.255.255 Class C: 192.168.0.0 - 192.168.255.255 Example: 192.168.0.3

42 .

What is the PoE?

Power over Ethernet (PoE) is a measure that allows Ethernet cables to simultaneously transfer data and power using a single network cable. This permits system integration and network installers to establish powered appliances in areas that lack electrical circuitry.

In addition, PoE stops the cost of installing extra electrical wiring, requiring professional electrical installers to assure that strict conduit regulations are followed. PoE technology transmits 10/100/1000 Mbps of data and 15W, 30W, 60W, and up to 90W of power budget to appliances over Cat5e, Cat6, and Cat6a. Cat7 and Cat8 Ethernet cables for the highest distance of 100m.

43 .

What is Round Trip Time?

RTT is also known as round-trip time is a crucial tool in defining the working condition of a network. It is the time between a request and the response in any kind of server on the internet. A round-trip time is measured in milliseconds. RTT can be examined and determined by pinging a specific address. It refers to the time taken by a network request to reach a final point and to revert back to the initial source.

44 .

What is NVRAM?

NVRAM (Non-volatile random-access memory) is a computer memory that can keep data when power to the memory chips has been turned off. NVRAM is a part of the larger type of non-volatile memory (NVM), which contains storage-class memory based on NAND flash. Flash memory chips are slow to read to and write than RAM chips, making them less well fitted for active computational memory.

45 .

What is the use of "Service Password Encryption"?

Service Password Encryption Command on CISCO Router/Switch Permits you to encrypt all passwords on your router so that they cannot be easily assumed from your running configuration. This command uses very weak encryption because the router has to decrypt the password very quickly for it to work.

46 .

What is the passive topology in CCNA?

When the topology enables the computers on the network only to listen and receive the signals, it is known as passive topology because they don't amplify the signals anyway.

47 .

What is RAID in CCNA?

RAID stands for Redundant Array of Independent Disks. RAID is a method which is used to standardize and categorize fault-tolerant disk systems. RAID levels provide various facilities like performance, cost, reliability, etc. These three are the mostly used RAID levels:

Level 0 : (Striping)

Level 1 : (Mirroring)

Level 5 : (Striping and Parity)

48 .

What is the point-to-point protocol in CCNA?

The point-to-point protocol is an industry standard suite of protocols which uses the point-to-point link to transport multiprotocol datagram. The point-to-point protocol is a WAN protocol used at layer 2 to encapsulate the frames for the data transmission over the physical layer.

Following are the features that point-to-point protocol provides :

* Link quality management : It is a technique to monitor the quality of a link. If it finds any error in a link, then the link is shut down.

* The point-to-point protocol also provides authentication.

* It provides some essential features such as authentication, error detection, link quality monitoring, load balancing, compression, etc.

Components of a point-to-point protocol are:

* Encapsulation : Point-to-point protocol encapsulates the network packets in its frames using HDLC protocol. This makes the PPP layer three layer independent.

* Link Control Protocol : Link Control Protocol is used for establishing, configuring and testing the data link over internet connections.

* Network Control Protocol : Point-to-point protocol is used in a data link layer in the OSI reference model. The data comes from the upper layer, i.e., transport layer or network layer is fully compatible with PPP due to the presence of a Network control protocol.

49 .

What is the difference between RIP and IGRP?

Basis of Comparison	RIP	IGRP
Full form	RIP stands for routing information protocol.	IGRP stands for interior gateway routing protocol.
Description	RIP is a distance vector-based routing protocol.	IGRP is a distance vector based interior gateway routing protocol.
Determination of route	RIP depends on the number of hops to determine the best route to the network.	IGRP considers many factors before decides the best route to take, i.e., bandwidth, reliability, MTU and hops count.
Standard	RIP is a industry standard dynamic protocol.	IGRP is a Cisco standard dynamic protocol.
Organization used	RIP is mainly used for smaller sized organizations.	IGRP is mainly used for medium to large-sized organizations.
Maximum routers	It supports maximum 15 routers.	It supports a maximum 255 routers.
Symbol used	RIP is denoted by 'R' in the routing table.	IGRP is denoted by 'I' in the routing table.
Administrative distance	The administrative distance of RIP is 120.	The administrative distance of IGRP is 100.
Algorithm	RIP works on Bellman ford Algorithm.	IGRP works on Bellman ford Algorithm.

50 .

What do you mean by OSPF?

OSPF (Open Shortest Path First) is basically a popular link-state routing protocol for IP networks that are used to connect to a large number of networks without any limitation on the number of hops. It determines the best route for delivering the data packets within an IP network. It has been implemented by a wide range of network vendors such as Cisco. It works on Dijkstra Algorithm.

* Firstly, a shortest-path tree is constructed.

* Secondly, the routing table is populated with the resulting best paths.

51 .

What are the conversion steps of data encapsulation?

Conversion steps of data encapsulation includes

Layer one, two and Three ( Application/presentation/session) : Alphanumeric input from the user is converted into Data

Layer Four (Transport) : Data is converted into small segments

Layer Five (Network) : Data converted into packets or datagrams and Network header is added

Layer Six (Data Link) : Datagrams or packets are built into frames

Layer Seven (Physical) : Frames are converted into bits

52 .

What is the difference between 'bit rate' and 'baud rate'?

A bit rate is defined as the total number of bits transmitted in one second whereas the baud rate is defined as the number of signal unit per second that is required to represent those bits.

Baud rate=bit rate / N,

where N = no. of bits represented by each signal shift.

53 .

Differentiate between forwarding lookup and reverse lookup in DNS?

Forward DNS and reverse DNS lookups are two different methods of accessing the Internet. The forward area is the DNS zone where the hostname is stored in the IP address relationship. Reverse DNS is the query method for determining the domain name associated with an IP address.

54 .

What are the differences between RIPv1 and RIPv2?

RIPv1 uses a standard route. Occasional updates do not have subnet information and no support for VLSM. This limitation makes it impossible to have subnets of different sizes within the same network category. In other words, all subnets in the network class should be the same size. There is also no router authentication support, which makes RIP vulnerable to various attacks.

RIPv2 is a vector distance route protocol defined in RFC 1723. As a phaseless protocol, it means, it included a subnet mask and network addresses in its router updates.

55 .

How is RIP select the best path to the remote network?

The main function of the router is to determine the best way to send the packets. To determine the best route, a router searches its router table to find a network address similar to the destination IP address of the package.

56 .

Explain the loop avoidance mechanism in RIP.

The following methods are used to avoid Routing Loops in RIP :

* The maximum hop count mechanism can be used to block Routing Loops. Vector distance protocols use the TTL (Lifetime) value in the IP data header to avoid loops.

* Split horizontal is the setting of the route that stops the route from being advertised back to where it came from.

* Route Poisoning is another way to avoid loops. If the router finds that one of its connected routes has failed, the router will be toxic to the route by providing endless metrics to it.

57 .

Difference between LSA & LSU in OSPF?

Link State Update (LSU) packs are OSPF Type 4. packs. Each LSA contains route, metrics, and topology information to define part of the OSPF network. The local router advertises the LSA inside the LSU package to its neighbors.