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Monday, October 14, 2019

CCNA (Cisco Certified Network Associate) Interview Questions and Answers

October 14, 2019
CCNA (Cisco Certified Network Associate) Interview Questions and Answers





Q :-  What is difference between Switch & Hub?
Ans :- Switch:
Switches operate at Layer 2 Data Link Layer
Address Learning
Forward / Filter decision using MAC address
Loop Avoidance
Breakup collision domains
Switches create separate collision domains but a single broadcast domain

Hub:
Hub operates at Layer 1 Physical Layer
No Filtering
No Addressing
Hub creates single collision domain and single broadcast domain
Make forwarding to all the ports when signal is arrived   

Q : What is PING utility?
Ans :-  PING – Packet Internet Gopher
A utility that verifies connections to one or more remote hosts. The ping command uses the ICMP echo request and echo reply packets to determine whether a particular IP system on a network is functional. Ping is useful for diagnosing IP network or router failures.

Q :-  What is a VLAN? What does VLAN provide?
Ans :-  VLAN – Virtual Local Area Network
Vlan is a logical grouping or segmenting a network connected to administratively defined ports on a switch, they provide Broadcast control, Security and Flexibility.

Q :-  What is Subnetting? Why is it used?
Ans :- Used in IP Networks to break up larger networks into smaller subnetworks. It is used to reduce network traffic, Optimized network performance, and simplify management i.e. to identify and isolate network problems.   

Q :- Difference between the Communication and Transmission?
Ans :- Communication is the process of sending and receiving data by means of a data cable that is connected externally.
Transmission means the transfer of data from the source to the destination.   

Q :- What is RAID in ccna?
Ans :- A method used to standardize and categorize fault-tolerant disk systems. RAID levels provide various mixes of performance, reliability, and cost. Some servers provide three of the RAID levels: Level 0 (striping), Level 1 (mirroring), and Level 5 (striping & parity).
  
Q :-  What are the two types of Transmission Technology available in ccna?
Ans :- Two types of Transmission Technology available in ccna are Point – to – Point and Broadcast   

Q :-  What is point-to-point protocol in ccna?
Ans :- An industry standard suite of protocols for the use of point-to-point links to transport multiprotocol datagrams.

Q :-  What are 10Base2, 10Base5 and 10BaseT Ethernet LANs?
Ans :- ss10Base2 an Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with a contiguous cable segment length of 200 meters (185mts). Known as Thinnet.

10Base5 an Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses baseband signaling, with a contiguous cable segment length of 500 meters. Known as Thicknet.

10BaseT an Ethernet term meaning a maximum transfer rate of 10 Megabits per second that uses two pairs of twisted-pair baseband signaling, with a contiguous cable segment length of 100 meters.  
 
Q :-  What are the possible ways of data exchange in ccna?
Ans :- Possible ways of data exchange in ccna are
Simplex
Half-duplex
Full-duplex   

Q :-  What is difference between Baseband and Broadband Transmission in ccna?
Ans :- In a baseband 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 :-  What is Protocol Data Unit in ccna?
Ans :- The processes at each layer of the OSI model.
Layers----------PDU
Transport-------Segments
Network---------Packets/Datagrams
Data Link-------Frames
Physical--------Bits 
 



Q :-  What are major types of Networks and explain?
Ans :- Peer-to-Peer Network
Computers can act as both servers sharing resources and as clients using the resources.
Server-based Network
Provide centralized control of network resources and rely on server computers to provide security and network administration   

Q :-  What is Passive Topology in ccna?
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.   

Q :- What is the Mesh Network?
Ans :- A network in which there are multiple network links between computers to provide multiple paths for data to travel.

Q :- How network Gateway is different from Routers?
Ans :- A device connected to multiple physical TCP/IP networks capable of routing or delivering IP packets between them.
Router
It’s a layer 3 device that connects 2 different networks and routes packets of data from one network to another. It breaks up Broadcast domain as well as Collision Domain.   

Q :- What is the network Brouter?
Ans :- It’s a Hybrid device that combines the features of both bridges and routers.   

Q :-  What is the network Subnet?
Ans :- A subnet is the subdivision of an IP network.   

Q :-  What is the Frame relay, in which layer it comes?
Ans :- Frame relay is an industry standard, shared access, switched Data Link Layer encapsulation that services multiple virtual circuits and protocols between connected mechanism.
Frame relay is a packet-switched technology.   

Q :- What is the Terminal Emulation, in which layer it comes?

Ans :- The use of software, installed on PC or LAN server, that allows the PC to function as if it were dumb terminal directly attached to a particular type of mainframe.
Telnet is also called as terminal emulation. It belongs to application layer.   

Q :- What is the Beaconing?

Ans :- An FDDI frame or Token Ring frame that points to serious problem with the ring, such as a broken cable. The beacon frame carries the address of the station thought to be down.
 
Q :- What is the Cladding?
Ans :- A layer of a glass surrounding the center fiber of glass inside a fiber-optic cable.

Q :- What is the Attenuation?
Ans :- In communication weakening or loss of signal energy, typically caused by distance.   

Q :- What is the ICMP protocol?
Ans :- ICMP – Internet Control Message Protocol
It is a Network Layer Internet protocol, which can report errors and status information. We can use the ping command to send ICMP echo request messages and record the receipt of ICMP echo reply messages. With these messages, we can detect network or host communication failures and troubleshoot common TCP/IP connectivity problems.

Q :- What are the NetBIOS and NetBEUI?
Ans :- NetBIOS – Network Basic Input / Output System
An application-programming interface (API) that can be used by programs on a local area network (LAN). NetBIOS provides programs with a uniform set of commands for requesting the lower-level services required to manage names, conduct sessions, and send datagrams between nodes on a network.
NetBEUI – NetBIOS Extended User Interface
An improved version of the NetBIOS protocol, a network protocol native to Microsoft Networking. It is usually used in small, department-size local area networks (LANs) of 1 to 200 clients. It can use Token Ring source routing as its only method of routing.   
  


Q :- What is the MAC 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 :- What is the ICMP protocol?
Ans :- ICMP – Internet Control Message Protocol
It is a Network Layer Internet protocol, which can report errors and status information. We can use the ping command to send ICMP echo request messages and record the receipt of ICMP echo reply messages. With these messages, we can detect network or host communication failures and troubleshoot common TCP/IP connectivity problems.
   
Q :- What is the difference between ARP and RARP?
Ans :- ARP – Address Resolution Protocol
The protocol that traces IP addresses to MAC addresses.

RARP – Reverse Address Resolution Protocol
The protocol within the TCP/IP stack that maps MAC addresses to IP addresses.

Q :- What is the difference between TFTP and FTP application layer protocols?
Ans :- TFTP – Trivial File Transfer Protocol
A stripped down version of FTP, easy to use and fast. TFTP has no Directory browsing, no Authentication and insecure it can only send and receive files.
FTP – File Transfer Protocol
The TCP/IP protocol used for transmitting files between network nodes. FTP allows access to both Directories and files, manipulating directories, typing file contents and copying files between hosts.
   
Q :- Explain 5-4-3 rule?
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 :- What is the MAU?
Ans :- MAU – Multistation Access Unit   

Q :- What is 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 :- What is the logical link control?
Ans :- One of two sublayers of the data link layer of OSI reference model, as defined by the IEEE 802 standard. This sublayer is responsible for error detection but not correction, flow control and framing.

Q :- What is the Virtual Channel?
Ans :- A logical circuit that is created by Virtual channel links. It carries data between two endpoints in a network.
The other name for Virtual Channel is Virtual Circuit.   

Q :- What is the Virtual Path?
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 :- What is the multicast routing?
Ans :-.Sending a message to a group multicast address is called multicasting, and its routing algorithm is called multicast routing.   




Q :- What is the IGP (Interior Gateway Protocol)?
Ans :- Any protocol used by an internetwork to exchange routing data within an autonomous system. E.g. RIP, IGRP and OSPF.   
   
Q :- What is OSI?
Ans :- Open System Interconnection. t was first name of 7 Layer

Q :- What is the default size of Frame?
Ans :- 1518 bytes   

Q :- Which layer are called upper layer?
Ans :- a) Application Layer - 7
b) Presentation Layer – 6
c) Session Layer – 5   

Q :- Tell me How many reserve ports?
Ans :-.0 – 1023

Q :- What is segmentation and fragmentation?
Ans :- To divide data in pieces is called segmentation and divide segmentation in pieces called Fragmentation.
  
Q :- Which layer called error detection layer?
Ans :-.Data link layer   

Q :- What is FCS?
Ans :- Frame Check Sequence -
CRC (Cyclic Redundancy Check) algorithm runs in switch that called FCS (Frame Check Sequence)   




Q :- What is Encapsulation and De-encapsulation?
Ans :- To send data called encapsulation and receive data called De-encapsulation.   

Q :- What is BIA?
Ans :- Burn in Address other name is MAC address

Q :- What is Size of IPv4 MAC Address?
Ans :-.48 Bits  

Q :-. Why MAC address called Physical address?
Ans :- Because it’s not changeable

Q :- What is Encapsulation and De-encapsulation?
Ans :- To send data called encapsulation and receive data called De-encapsulation.   

Q :- What is BIA?
Ans :- Burn in Address other name is MAC address

Q :- What is Size of IPv4 MAC Address?
Ans :-.48 Bits  

Q :-. Why MAC address called Physical address?
Ans :- Because it’s not changeable

Q :- Who controls MAC address uniqueness and how?
Ans :- IEEE (Institute of Electrical Electronics and Engineering) Controls its uniqueness.
They divide 48 bits MAC address in two parts. (allindiajobs.in)
First 24 bits part called OUI (Organizational unique identifier) and other 24 bits are device code.
   
Q :- How we can see MAC address from DOS Prompt?
Ans :- ipconfig/all

Q :- Why IP address called logical address?
Ans :- Private IP called logical address because they are change able.   

Q :- What is the size of IPV4?
Ans :- 32 bits  

Q :- What is Syntax of IPV4?
Ans :-.DOT

Q :- How many types of IPS?
Ans :-.Three Types of IP
1- Public
2- Private
3- Special IP   

Q :- What are the ranges of private IPS?
Ans :-.A Class = 10.0.0.0 – 10.0.0.255
B Class = 172.16.0.0 – 172.31.0.0
C Class = 192.168.0.0 – 192.168.0.255   

Q :- What is the difference between bus topology and HUB?
Ans :- Hub is Centralized device ( series ) .Bus topology is Decentralized device (in parallel)   

Q :- Is hub intelligent device?
Ans :-.  No; because.

Q :- Which protocol switch use for filling its MAC-Table?
Ans :- ARP – Address Resolution Protocol   

Q :- What is CAM?
Ans :-. Content Address Memory. its another name of MAC address table.   
 e it not use header  

Q :-. Which type for communication switch do?
Ans :- In case of any new event switch do broadcast, after that always do Unicast.   

Q :- If line down and protocol also down; in this case which layer move problem?
Ans :-.Physical Layer – Layer 1   

Q :-. If line up, but protocol down which layer should be troubleshot?
Ans :-.Data link problem – Layer 2

Q :-. On which base switches take decisions?
Ans :-.Mac Address

Q :-. How ARP brings MAC address for switch?
Ans :-.Through Broadcast  

Q :-. How many collision domains are in switch?
Ans :- Equal number of ports   

Q :- How many broadcast domains are in Switch?
Ans :- One   

Q :- What is the subnetmask of / 27 in network based and host based?
Ans :- In network based 224 { 128+64+32}and in host based 248 (128+64+64+16+8)



Q :- What will be the prefix length of 224 in VLSM?
Ans :- 27 (carry 3 bits from host (128+64+16=224) and add in network ports (24+3=27) )   

Q :- How many valid IP will b in /21 in route Summarization?
Ans :- 1044   

Q :- In which protocol you manually enable route summarization?
Ans :- OSPF
  
Q :- In which protocol supenetting is enable by default?
Ans :-.RIPv2 and EIGRP

Q :- What is MAC address size of IPv6?
Ans :- 64 bits

Q :- Default Packet Size of IPv6?
Ans :- 8 Bytes = 16*8 =128 bit   

Q :- How many fillers we can put in one IP of IPv6?
Ans :-.ONE (:: called filler)

Q :- Which mathematically form used inIPv6?
Ans :-.Hexadecimal 
 
Q :- What is quality of IPv6?
Ans :- a) Router processing will rapid because field size wills 8 bytes (but in IPv4 it was 12 byres)
b) No Fragmentation
c) No Checksum

Q :- Define Network?
Ans :-.Communication, Resource sharing and Media (When multiple host share their resources with each other OR when multiple devices connect with each other for resource sharing )   

Q :- Explain Types of communication in IPv4?
Ans :- Unicast, Multicast and Broad cast   

Q :- Types of communication in IPv6 ?
Ans :- Unicast, Multicast and Anycast

Q : Types of Resource Sharing?
Ans :-.Intranet , Extranet and Internet .

Q :- What is Collision?
Ans :-.When signal hits each other, collision accord.
   
Q :- Which Type of Transmission Bus Topology Support?
Ans :-.Half Duplex

Q :- What is the difference between half duplex and full duplex?
Ans :-.In half duplex, sender should b one. In full duplex, sender can be multiple.


Q :- Which way of communication bus topology use?
Ans :-.Broadcast   

Q :- If there is only 2 Host in Bus Topology is that possible collision accord?
Ans :-.Yes, because end terminal will not absorb signals. Signal will be bounce back and collision will accord.

Q :- HUB in Star topology or Bus Topology?
Ans :-.In star topology, but logically works like a bus topology.   

Q :- What we called 64 Bit Mac-address in IPV6?
Ans :-EUI= Enhanced universal identifier – 16 bits add in IPv6 so it’s called EUI rd.   

Q :- What is loop back IP in IPV6?
Ans :- 1 and ping 6

Q :- Which command we use for ping in IPv6?
Ans :- Ping6 source IP -s Destination IP   

Q :- How many types of router?
Ans :-
Two types
i) Modular
ii) Non-

Q :- When we use Router?
Ans :-.For communication between different networks.   

Q :- Which works router Do?
Ans :-
1- Path selection and
2- Packet Switching {frame relay}   

Q :- What cable called V.35?
Ans :-.Serial Connectivity cable

Q :- How many types of Ethernet?
Ans :- 4 types
i) Ethernet
ii) Fast Ethernet
iii) Gigabit
iv) 10 Giga.   

Q :- Which cable called roll-over?
Ans :-.Console access able

Q :- Which cable we connect in DB-9?
Ans :-.Roll over calbe

Q :- How many ways to access router?
Ans :-.3 ways
i) Telnet (IP)
ii) AUX (Telephone)
iii) Console (cable)   

Q :- What is IOS?
Ans :-.Internet Operating system. Its router’s operating system.   

Q :- Which mode called privilege mode?
Ans :-.Second mode.