ccna interview questions and answers

Part - 51 CCNA Interview Questions and Answers

301 Repeaters work at which layer of the OSI model?

A.) Network

B.) Session

C.) Transport

D.) Physical

Ans D

Repeaters work at the Physical layer of the OSI model by regenerating the signal to extend the distance it can travel.

302 What protocols can you use while testing Trace?

A.) DECnet

B.) CLNS

C.) IP

D.) Old Vines

E.) Vines

F.) Chaos

Ans B C D E

Type Trace ? At the router command prompt to see a list of available supported protocols for tracing routes to IP addresses or Name addresses.

303 What utility can you use to see the path a packet takes through an internetwork?

A.) Route

B.) SNMP

C.) Trace

D.) Ping

Ans C

Trace - Uses Time-To-Live (TTL) values to generate messages from each router used along the path. This is very powerful in its ability to locate failures in the path from the source to the destination.

304 What is true about frame-relay DLCI?

A.) DLCI represents a single physical circuit

B.) DLCI is optional in all frame-relay networks

C.) DLCI identifies a logical connection between DTE devices

D.) DLCI is used to tag the beginning of a frame with VLAN information Ans C Data Link Connection Identifier (DLCI). A frame-relay service provider typically assigns DLCI values that are used by frame-relay to distinguish between different virtual circuits on the network. For the IP devices at each end of a virtual circuit to communicate, their IP addresses are mapped to Dlci. Every DLCI value can have a global or local meaning.

305 Which frame has a Type field to identify the upper-layer protocol?

A.) 802.3

B.) 802.2

C.) 802.5

D.) Ethernet_II

Ans D

Ethernet_II has a Type field to identify the upper-layer protocol. This is best seen by capturing packets with a sniffer and examining the packet.

306 Which protocol will let neighbor routers know if your internetwork experienced congestion on a serial port?

A.) BootP

B.) IP

C.) ICMP

D.) ARP

E.) FTP

F.) RARP

Ans C

Internet Control Message Protocol - ICMP is a management protocol and messaging service provider for IP. Its messages are carried as IP datagrams. ICMP is used in the following events:
Destination Unreachable - If a router cannot send an IP packet any further, it uses an ICMP echo to send a message back to the sender notifying it that the remote node is unreachable. Buffer Full - If a routers memory buffer is full ICMP will send out a message to the originator. Hops - Each IP datagram is assigned a path. This consists of hops. If it goes through the maximum number of hops, the packet is discarded and the discarding router sends an ICMP echo to the host. Ping - Ping use ICMP echo message to check connectivity.

307 What do you use the Aux port for?

A.) Console

B.) Terminal editing

C.) Modem

D.) Backup logging

Ans C

The auxiliary port is used to connect a modem to for dial backups.

308 The CSMA/CD Ethernet IEEE committee is defines as which of the following?

A.) 802.2

B.) 802.3

C.) 802.4

D.) 802.5

Ans B

The IEEE standard for Carrier Sense Multiple Access / Collision Detection is 802.3. Also know as Ethernet.

309 How many Frame-relay encapsulation types are available with Cisco routers?

A.) Four

B.) Two

C.) Five

D.) Three

Ans B

The two types of Frame relay encapsulation are Cisco and IETF.

310 What is the maximum hop count for Link-State protocols?

A.) 15

B.) there is no hop count limit

C.) 256

D.) 16 Ans B Link-state-based routing algorithms – also known as shortest path first (SPF) algorithms, maintain a complex database of topology information. Whereas the distance vector algorithm has non-specific information about distant networks and no knowledge of distant routers, a link-state routing algorithm maintains full knowledge of distant routers and how they interconnect.

311 What information can you get from CDP info: (choose all that apply)

A.) Hardware platform

B.) One address per protocol

C.) Software platform

D.) Hostname

E.) The same info as show version

F.) Incoming/outgoing port

Ans A B D E F

All of the above except the software platform can be seen with the CDP information.

312 How does the cut-through switching technique work?

A.) By using broadcast address as source addresses

B.) The switch waits only for the header to be received before it checks the destination address and starts forwarding the packets

C.) The LAN switch copies the entire frame into its onboard buffers and then looks up the destination address in its forwarding, or switching, table and determines the outgoing interface

D.) By using a Class I repeater in a collision domain

Ans B

Cut-Through switching copies only the destination address which is the first 6 bytes after the frame preamble into its buffer. The LAN switch then looks up the destination address in its switching table and determines the outgoing interface. The frame is then sent to the interface. A cut-through switch provides reduced latency because it begins to forward the frame as soon as it read the destination address and determines the outgoing interface.

313 What is the protocol number for TCP?

A.) 80

B.) 21

C.) 11

D.) 6

Ans D

Transmission Control Protocol - TCP is a connection oriented transport layer protocol with built in reliability. It takes a large block of data and breaks it down into segments. It numbers and sequences each segment so the destination's TCP protocol can re-assemble it back into the original order. TCP uses acknowledgements via sliding windows. It has a large overhead due to built in error checking. The protocol use protocol # 6.

314 Which of the following are Presentation Layer standards?

A.) JPEG and PICT

B.) MPEG and MIDI

C.) ASCII and EBCDIC

D.) NFS and SQL

Ans A B C

For example, the Presentation layer would be responsible for converting from EDCDIC to ASCII. Data compression, decompression, encryption, and decryption are presentation layer. Presentation layer standards include MPEG, MIDI, PICT, TIFF, JPEG, ASCII, and EBCDIC.


315 What is the administrative distance for RIP?

A.) 100

B.) 90

C.) 120

D.) 110

The correct answer(s): C Routing Information Protocol (RIP) is a distance vector routing protocol that uses hop count as its metric. The maximum hop count is 15, 16 hops is considered unreachable. RIP updates are broadcast every 30 seconds by default. RIP has an administrative distance of 120.

316 IP standard access lists use which of the following as a basis for permitting or denying packets?

A.) destination address

B.) port

C.) protocol

D.) source address

Ans D

For Standard access lists, only the source address is used as a basis for permitting or denying packets.

317 If a frame is received at a switch and only the destination hardware address is read before the frame is forwarded, what type of switching method is this?

A.) Store-and-drop

B.) Latency

C.) Store-and-forward

D.) Cut-through

Ans D

Cut-Through switching copies only the destination address which is the first 6 bytes after the frame preamble into its buffer. The LAN switch then looks up the destination address in its switching table and determines the outgoing interface. The frame is then sent to the interface. A cut-through switch provides reduced latency because it begins to forward the frame as soon as it read the destination address and determines the outgoing interface.

318 What is the purpose and default value of the CDP timer command?

A.) 90 seconds; interval before an entry expires

B.) 60 seconds; interval between updates

C.) 60 seconds; interval before an entry expires

D.) 90 seconds; interval between updates

Ans B

The CDP timer controls when the update of CDP information should be sent to the neighbor router.

319 Choose the following that are benefits to segmenting with router:

A.) Flow Control

B.) Manageability

C.) Multiple Active Paths

D.) Explicit packet lifetime control

Ans A B C D

All of the above are benefits of segmenting with a router.

320 When discussing static routes, what is the gateway parameter used for?

A.) Determining the dynamic route

B.) Defining the subnet

C.) Defining the Administrative Distance

D.) Determining the next hop

Ans D

The gateway parameter determines the path to the next router.

321 Which layer hides details of network dependent information from the higher layers by providing transparent data transfer?

A.) Transport

B.) Physical

C.) Data Link

D.) Session

E.) Application

F.) Network

Ans A

The Transport layer does the following: Responsible for end-to-end integrity of data transmission. Handles multiplexing upper-layer application, session establishment and tear down of virtual circuits. Hides details of network dependent info from the higher layers by providing transparent data transfer. The 'windows' works at this level to control how much information is transferred before an acknowledgement is required.

322 What information is provided by the local management interface (LMI)?

A.) LMI encapsulation type

B.) The current DLCI values

C.) The status of virtual circuits

D.) The global or local significance of the DLCI values

Ans B C D

LMI is a standard related to Frame Relay. It provides information related to PVCs.

323 Which layer defines the physical topology?

A.) Application

B.) Transport

C.) Network

D.) Data Link

E.) Physical

F.) Session

Ans E

The Physical layer deals with the actual physical medium and the method of transporting 1s and 0s.


324 What key do you use to view the last command?

A.) Left Arrow

B.) Space Bar

C.) Up Arrow

D.) Right Arrow

Ans C

CTRL+P as well as the Up Arrow keyboard commands will show the last command.

325 Which of the follow do not belong to the customer?

A.) CO

B.) DCE

C.) Router

D.) CPE

E.) Demarc

F.) DTE

Ans A E

Central Office (CO) - A switching facility that provides the nearest point of presence for a provider's WAN service. Demarcation (Demarc) - The point at which the CPE ends and the local loop portion of the service begins. Usually the telecommunications closet at the subscriber's location. CPE, DTE, DCE, and the router are all typically owned by the customer. DTE devices are usually routers, DCE devices are CSUs/DSUs, or WAN interfaces that have a built in CSU/DSU in the router. CPE stands for Customer Premise Equipment.