CCNA Interview Question and Answer 2020

CCNA Interview Questions and Answers in 2020 networkingguruji1.com/2020/01/ccna-interview-questions-and-answers-in-2020.html

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1.

What is a network?

It's a communication media that is used to exchange information between devices.

2. What are the criteria of a good network?

Performance, Reliability and Security.

3. What is a point-to-point connection type?

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A single link between only two devices.

4. What is a multipoint connection type?

A single is shared by more than two devices.

5. What is LAN? A network which is locally situated within the building.

6. What is WAN? The network in which data from a source has to travel a long distance to reach the destination device.

7. What is a full-duplex mode of communication?

Both send and receive at a time. Ex: Telephone or mobile communication, modern data network.

8. What is a half-duplex mode of communication?

Both send and receive, but not at a time. Ex: Walky-Talky, HUB. 9. What is the simplex mode of communication?

Only send or only receive. Ex: Keyboard, Monitor, etc.

10. What is topology?

Topology is nothing but a Network connectivity design view.

11. What is the disadvantage of Full Mesh topology?

Cost.

12. What do you mean by Logical topology?

A logical topology/signal topology is the path that the data signals take through the physical topology.

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"ccna interview question and answer" 13. What is the relation between Bit and Byte?

8 Bits make 1 Byte.

14. What is the use of Bit and Byte?

The bit is used to measure the speed (Bandwidth). A byte is used to measure storage capacity(Space).

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15. What is the Leased line WAN? Dedicated connection to connect two or more LAN network.

16. What are the Protocols for wan?

Following are WAN Encapsulation protocol, all works at the data link layer in the OSI model.

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HDLC or High-Level data link control PPP or Point to point protocol Frame Relay ATM 17. What is wan?

WAN is a type of connection, connecting two or more LAN network.

18. What is HDLC? The default serial/WAN encapsulation on Cisco routers is cisco HDLC, it is data link layer (Layer 2 ) protocol. Used in p2p WAN link, like a leased line.

19. What is PPP? The open standard point to point (PPP) wan protocol for transporting IP traffic across a point to point links. Works at layer 2.

20. What are the components of PPP? LCP or link control protocol Authentication Protocol NCP or Network control protocol 21. What are authentication protocols are used by PPP? Pap or password Authentication protocol Chap or challenge handshake authentication protocol "ccna questions and answers" 22. What is the advantage of PPP or HDLC? PPP supports authentication 4/12

PPP supports multilink configuration PPP supports mismatched subnet PPP can be used in any vendor’s device 23. What is VPN? VPN stands for a virtual private network, which means it virtually creates a private network over the physical public network (internet).

24. What is GRE? GRE is a tunneling mechanism used to create a tunnel between two endpoints. It is a site to site VPN technology.

25. What is the protocol number used by GRE? 47 26. What is DMVPN? DMVPN is a point to multipoint layer 3 overlay VPN Logical hub and spoke topology Direct spoke to spoke traffic is supported.

DMVPN uses a combination of of‌.

Multipoint GRE Tunnel (MGRE) Next hop Resolution Protocol (NHRP) IPSEC Routing 27. What is NHRP?

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NHRP or next-hop resolution protocol. Next hop resolution protocol (NHRP) is a resolution protocol that allows a next-hop client (NHC) to dynamically register with next-hop servers (NHss).

28. Why do we need HSRP? It is a first-hop redundancy protocol. It provides redundancy in first hop.

29. What is the difference between HSRP v1 and v2?

HSRP V1 Supports only ipv4 Group number range 0-255 Ipv4 multicast address is 224.0.0.2 A unique identifier for each router is not supported.

Smallest unit for hello is second Mac address used oooo.occ7.acxx HSRP V2 Supports both ipv4 and ipv6 Group number ranged from 0-4095 Ipv4 multicast address 2224.0.0.102 It supports a unique identifier for each router Smallest unit for hello timer is a millisecond Mac address used OOOO.0C9F.FXXX. Note: X refers the group number in HEX

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And Disabling Dynamic Trunking Protocol (DTP)….Basic to advance Level... & Configuration..... Click Here 30. What is PPPOE? PPPOE stands for point to point protocol over Ethernet, a network protocol for encapsulating point to point protocol (PPP) frames inside an Ethernet frames. It is used mainly with DSL services where individual users connect to DSL modem over Ethernet.

PPPOE allows us to configure PPP over an Ethernet link.

31. What is QoS? A tool networking devices use to treat packets differently as packets pass through the device.

"CCNA Fresher Basic Interview Question With Answer" 32. What is ASN? Autonomous System Number (ASN) as a number is used to identify a group of networks.

Which is under single administrative control that shares the same routing policies.

33. What is AS number range from?

Originally 2 bytes in size, Values 0 – 65535 Public ASN 1 -64511 (Like public ipv4 address) Private ASN 64512 – 65535 (Like private ipv4 address) 34. Why do we use BGP? BGP has better route filtering control and route manipulation control then ISP (interior gateway protocol) In the case of a multi-home scenario.

In case of connecting to another routing domain or to another as.

If I have my own public IP address space.

If I am an ISP. If I have an ASN.

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35. What is AD Value of BGP? BGP Ad value, For IBGP it is 200 For EBGP it is 20 36. Which TCP port is used by BGP? 179 37. What is EBGP? EBGP is used for external neighbors. It is used between different autonomous number.

38. What is IGBP? IBGP is used for internal neighbors. It is used within the same an autonomous system number.

39. Why BGP is called path-vector routing protocol?

BGP is a path vector protocol. A path vector protocol does not rely on the metric to select the best path.

Instead, path vector protocols different tag or Attributes to select best path.

40. What are the different BGP message types?

OPEN, KEEPALIVE, UPDATE, NOTIFICATION. 41. What is the significate of the network command in BGP? In BGP the network statement is used to advertise network into BGP. 42. What are T1 and E1?

T1 is a digital data transmission medium capable of handling 24 simultaneous connections running at combined 1.544 Mbps. T1 combines these 24 separate connections, called channels or time slots, onto a single link. Here 23 channels are used for data transmission and 1 is used for signaling.

E1 is the European format of digital transmission. E1 links are similar to T1 links except that 8/12

they carry signals at 2.048 Mbps. Each link has 32 the channel, and each channel transmits at 64 kbps. Here 30 channels are used for data transmission and 2 are used for signaling.

43. What is MPLS? Multiprotocol Label switching is originally cisco proprietary tag switching technology name implies two important parts…….

Multiprotocol Label Switching Multiprotocol means can transport different L2 and L3 payloads.

Label switching means switch traffic between interfaces based on locally significant label values.

44. Why do we MPLS? It is fast-forwarding technology.

Offer L2/L3 VPN services to customers, no need for overlay VPN (GRE IPSEC) model.

BGP free core saves routing table space on provider (P) routers.

"CCNA Interview Questions and Answers in 2020"

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45.In which layer does MPLS work?

MPLS header site between L2 and L3 46. What is the use of LDP? LDP(Label Distribution Protocol) is used to discover MPLS neighbors and exchange label information.

47. What is defined by CE, PE and p routers?

CE or Customer Edge: This Device is the last device in the customer’s network, any L2 or L3 device. This device does not use MPLS. PE or Provider Edge: Last ISP device, at the edge of ISP’s network. It receives packets or frames from CE and adds labels before forwarding those frames or packets to the core. Also known as label edge Router (LER).

P or Provider: At the core of the MPLS network, connect to PE routers and other p routers. It switches packets based on their labels and removes labels. Also known as label switch router (LSR) or Transit Router.

48. What is the security future of the IPSEC VPN? Confidentiality or privacy Authentication Data Integrity Anti Reply 49. What is the advantage of using a VPN? Secure Low cost than other Internet connections.

50. What is IPsec?

Internet protocol security (IPsec) is a protocol suite for secure internet protocol (IP) communications that work by authentication that works by authenticating and encrypting each IP packet of a communication session.

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51. Why do we need IPSEC? IPSEC (IP Security) is used to source IP traffic over an un-trusted network (such as the internet) by enabling a system to select required security protocol (AH or ESP), algorithms and cryptographic keys.

52. What is SSL? A web-based VPN technology.

Provides secure connection as well as communication between a web browser and the webserver.

SSL port number at L4 is 443.

SSL encrypts data and authenticates the user. After that Http protocol gets HTTP message over SSL VPN connection.

It is a built-in feature in every web Browser.

"CCNA Interview Questions & Answers" 53. How do HSRP works?

HSRP works active/Standby mode, one router is active at a time and others remain passive.

HSRP implements a virtual IP address of the same subnet of the physical interface IP address and its corresponding MAC address.

ALL HSRP routers known this virtual IP and MAC but the only active router uses these addresses at any point in time.

54. What is HSRP Preemption?

If already an active router is found and default preemption is configured, the current active router becomes a standby router even if it has the Higher priority value. If the configuration is changed from the default, the local router becomes active if it has priority better than the current active router’s priority.

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55.Does HSRP support load balancing?

Yes, per subnet basis.

56. When do both routers of a subnet get active when using HSRP? If there is no exchange of HSRP hello among the HSRP routers.

At the time of booting both have the same HSRP priority.

If both the routers have the same IP address on their physical interface.

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This is the full "CCNA Interview Questions and Answers in 2020" Thank you So Much.

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