Friday, July 15, 2011

CCNA Interview Questions Part 3

1.      Which OSI layer handles physical address, network topology?
* Presentation
* Physical
* Transport
* Application
* Data-Link
* Network
Correct answer: E
Layer 2 the Data-Link layer performs this function.
2.      Identify 2 reasons for disabling CDP?
* If the router is not configured for RIP
* Save bandwidth by eliminating overhead
* If the router is configured for Appletalk
* When connected to a non-Cisco router
Correct answer: B D
CDP can be disabled here are a couple of reasons. Connecting a Cisco router to a non-Cisco router. Don’t want to exchange CDP information to save bandwidth.

3.      Identify 3 characteristics of ISDN?
* Transports voice and data
* Transports voice only
* Support both BRI and PRI
* Runs over existing phone lines
* Same as X.25
Correct answer: A C D
ISDN supports voice, data, and video. It runs over existing phone lines and supports 128K (BRI) and T1 (PRI).
4.      Identify the 3 characteristics of IGRP?
* Uses hop count as a metric
* Supports multiple unequal paths
* Administrative distance is 100
* Configured with an Autonomous system number
* Link state
Correct answer: B C D
IGRP is a distance vector routing protocol, it’s degree of trustworthiness is 100, it can support up to 6 un-equal paths and must be configured with an autonomous system number.
5.      Identify 2 features of PPP CHAP authentication?
* Username and password is sent in clear text
* Authentication messages are sent periodically during the connection
* Less secure then PAP
* Local router ‘challenges’ the remote router
Correct answer: B D
PPP CHAP authentication message are sent periodically during the connection by challenging the other end of the connection.
It is more secure than PAP and passwords and username are encrypted.
6.      Identify the default IPX serial encapsulation?
* Novell-Ether
Correct answer: D
The default IPX serial encapsulation is HDLC.
7.      Identify the hardware component that stores the backup configuration?
* Flash
Correct answer: B
NVRAM contains the backup config. RAM is the dynamic memory area, ROM contains the boot strap code and Flash contains the IOS.
8.      Identify the extended IP access-list number range?
* 600 - 699
* 1 - 99
* 900 - 999
* 100 - 199
Correct answer: D
The extended IP access-list range is 100-199.
9.      Identify 3 Fast Ethernet technologies?
* 100 Base FastEther
* 100 Base FX
* 100 Base T4
* 100 Base TX
Correct answer: B C D
10.  BaseFastEther is false. 100 Base FX, TX and T4 are all valid.
11.  Identify the OSI layer which is responsible for end-to-end connections?
* Network
* Transport
* Session
* Data link
Correct answer: B
Layer 4 is the Transport layer and is responsible for end-to-end connections.
12.  Identify the 2 characteristics regarding MAC addresses?
* Contains a network portion and host portion
* Always assigned by System Administrator
* 48 bits long
* Contains a vendor code and serial number
Correct answer: C D
MAC addresses are assigned by the vendor. Each MAC address is 48 bits long and made up of 24 bits vendor code and 24 bits serial number.
13.  Identify the number range for IPX SAP filters?
* 900 - 999
* 1000 - 1099
* 800 -899
* 100 - 199
Correct answer: B
The IPX SAP filtering range is 1000-1099.
14.  What is the purpose of ARP?
* IP to host name resolution
* Host name to IP address resolution
* Mac to IP address resolution
* IP to Mac address resolution
Correct answer: D
Address Resolution Protocol resolves the MAC address if the IP address is known. It is a layer 3 protocol.
15.  Which OSI layer establishes, maintains and terminates sessions between hosts?
* Application
* Physical
* Data-Link
* Presentation
* Network
* Session
Correct answer: F
Layer 5 the Session layer performs this function.
16.  Which statement is true regarding Administrative distance?
* It is a metric
* Number of hops between two routers
* Trustworthiness of the routing information
* RIP Administrative distance is 100
Correct answer: C
Administrative distance is rating of trustworthiness of the routing information. The lower the AD the better the information.
17.  Identify the purpose of the Ping command?
* Share routing information with a neighbor router
* Transmit user data when buffers are full
* Test connectivity at layer 3
* Test entire protocol stack
Correct answer: C
The ping command tests layer 3 connectivity.
18.  Identify the order of the 5 step encapsulation?
1. Create the segment
2. Convert the frame to bits
3. Create the packet
4. Create the frame
5. User creates the data
* 1,2,4,2,5
* 2,1,3,4,5
* 5,1,3,4,2
* 5,3,4,1,2
Correct answer: C
Cisco 5 step encapsulation.
1) User creates Data
2) Data is converted into a segment at layer 4
3) The segment is converted to packet at layer 3
4) The packet it converted into a frame at layer 2
5) The frame is converted into bits at layer 1
19.  The Cisco IOS is stored where?
* CD
* Flash
Correct answer: C
By default the Cisco IOS is stored in flash.
20.  Sequence and acknowledgement numbers are used for?
* Layer transitioning
* Flow control
* Port number addressing
* Reliability
Correct answer: D
TCP uses sequence numbers and acknowledgements to implement reliability.
21.  Identify IPX GNS and it’s purpose?
* Go Network Server - sends a print job to a network server
* Get Nearest Server - locate the nearest server
* Guaranteed Network Services - allocates resources to users
* Get Notes Server - locates Domino Server
Correct answer: B
GNS stands for Get Nearest Server, initiated by a workstation.
22.  Identify the true statement regarding subnetting?
* Allows for more host address
* Borrow bits from the network portion of the address
* Allows for unlimited number of networks
* Borrow bits from the host portion of the address
Correct answer: D
Subnetting involves borrowing bits for the host portion of the address to be used to subnet addressing.
23.  Inverse ARP serves what purpose?
* Method for a local router to introduce itself to the remote end of the connection
* Broadcast a routing table update
* Identify MAC addresses if the IP address is known
* Sent every 10 seconds used to verify the Frame Switch is still active
Correct answer: A
Inverse ARP operates in a Frame Relay network so the two end points can identify themselves to each other.
24.  Identify 3 characteristics of a MAC address?
* Burned into the NIC
* 48 bits long
* Length is 32 bits
* Used to deliver the frame to the end device
* Contains a network portion and a host portion
Correct answer: A B D
The MAC address is 48 bits long not 32. It does NOT contain a network and host portion with the address. It is used to deliver the frame to the destination device.
25.  Identify 3 IP routing protocols?
Correct answer: A C D
AURP and ICMP are not routing protocols.
26.  Identify the type of routing protocol that exchanges entire routing tables at regular intervals?
* Link state
* Interior gateway protocols
* Appletalk routing
* Distance vector
Correct answer: D
Distance Vector routing protocols exchange entire routing tables with it’s neighbors. Link State routing protocols exchange LSP’s to share information regarding the networks they know.
27.  Identify the type of hardware required to connect a Token ring network to an Ethernet network?
* Repeater
* TR-Enet
* Router
* Token Ring to Ethernet translation hub
Correct answer: C
Routers are used to connect dissimilar networks with different access-methods, like connecting Token Ring to Ethernet.
28.  Identify 3 characteristics regarding CDP?
* On by default
* Shows only directly connected neighbors
* Requires IP or IPX
* 60 second update interval by default
* 30 second updates interval by default
Correct answer: A B D
CDP stands for Cisco Discovery Protocol. It is used to discover directly connected neighbors, it is on by default and has a 60 second update interval by default.
29.  Identify 2 transport layer protocols?
* IP
Correct answer: B E
TPC and UDP are 2 layer4 Transport protocols.
30.  Identify 2 features of X.25?
* Supports only IP
* Utilizes switched and permanent virtual circuits
* Contains minimal flow control and error recovery
* Utilizes LAPB as it’s data-link protocol
Correct answer: B D
X.25 utilizes LAPB and uses switched and permanent VC’s. It supports multiple layer protocols and is heavy laden with error detection and correction mechanisms.
31.  Identify the purpose of the Trace command?
* Explorer packet transmitting routing information
* Test connectivity
* Determine the path a packet is taking through the network
* Transmits user data when buffers are full
Correct answer: C
The trace command is used to determine the path a packet has taken through the network.
32.  Identify the purpose of the TCP 3 step handshake?
* Setup a un-reliable connection
* Initialize routing tables
* Synchronize sequence numbers between hosts
* Connection tear down process
Correct answer: C
The 3 step handshake establishes the parameters required for a TCP connection. During the handshake process sequence numbers are synchronized allowing for the end points to properly acknowledge and re-assemble the segments.
33.  Identify 2 PPP characteristics?
* Is proprietary to Cisco
* Supports authentication
* Support compression
* Run on a multi-access network
Correct answer: B C
PPP supports authentication; PAP and CHAP. It also supports compression; Stacker and Predictor.
34.  Which statement is true regarding half duplex?
* Only works in a point-to-point configuration
* Allows for transmitting and receiving but not a the same time
* Allow for transmitting and receiving of data simultaneously
* Doubles the bandwidth
Correct answer: B
Half duplex is analogous to a single a lane bridge, it can handle traffic in both directions but no at the same time.
35.  Identify the purpose of the wildcard mask?
* Match a certain portion of the IP address while ignoring the rest of the address
* Determine the class of the IP address
* Determine the network portion of an IP address
* Hide the host portion of an IP address
Correct answer: A
The purpose of the wildcard mask to match a certain portion of the IP address while ignoring the rest.
36.  Identify the OSI layer associated with bits?
* Physical
* Network
* Binary
* Data link
Correct answer: A
The Physical layer converts the frames to bits.
37.  Identify the type of routing protocol that maintains a topological database of the network?
* Topological state
* Shortest Path First
* Link state
* Distance vector
Correct answer: C
Link State routing protocols maintain a database that lists all the networks in the internetwork.
38.  Identify the 3 major functions at layer 3 of the OSI model?
* Forwarding process
* Logical addressing
* End-to-end connections
* Path selection
* MAC address examination
* Network monitoring
Correct answer: A B D
Layer 3 determines the path, forwards the packet and implements software or logical addressing.
39.  Identify the 2 rules used when configuring a Distance Vector routing protocol?
* Physically connected network(s)
* Configure the classful address, no subnets
* Enable CDP so neighbors can be detected
* Configure all networks in Area0
Correct answer: A B
When configuring a Distance Vector routing protocol only assign the physically connected networks with the classful address only.
40.  Identify 3 characteristics of an IP address?
* Contains a network portion and a host portion
* 32 bits long
* Unique to each network
* Part of the default Cisco configuration
* Referred to as the hardware address
Correct answer: A B C
An IP address is 32 bits long, it is referred as the logical or software address. It contains a network and host portion. Each IP address is unique.
41.  Identify 3 feature of access-lists?
* Implicit deny will deny any packets not matched
* Processed sequentially from bottom to top
* Processed sequentially from top to bottom
* If a packet is denied it would be tested against the remaining statements in the access-list
* Once a match is made the packet is either denied or permitted
* Enabled on all interfaces by default
Correct answer: A C E
Access-list are processed from top to bottom, once a match occurs the packet is either denied or permitted and is no longer tested and if no match occurs the packet is denied via the implicit deny.
42.  Which OSI layer performs code conversion, code formatting and encryption?
* Physical
* Data-Link
* Application
* Transport
* Presentation
* Network
Correct answer: E
Layer 6 the Presentation layers performs this function.
43.  Identify the 3 methods routers learn paths to destinations?
* Dynamic routing
* None of the above, configured by default
* Default routes
* Administrative distance
* Static routes
Correct answer: A C E
Routers can learn paths via 3 different sources; static routes, dynamic routing protocols (i.e. RIP) and default routes.
44.  Identify the purpose of the following command ‘ip route′
* Enabling a dynamic routing protocol
* Creating a static route to the network
* Teaches the router about the distant network and how it can be reached via
* Assigning the IP address to an interface
Correct answer: C
A static routes teaches the router about a distant network and the next hop to reach that network. Command syntax:
ip route network-address subnet-mask next-hop-address
45.  Based upon the 1st octet rule identify the range for a Class A address?
* 1 - 126
* 192 - 223
* 128 - 191
* 1 - 191
Correct answer: A
Class A address has the 1st octet between 1 - 126. Class B between 128 - 191 and Class C between 192 - 223.
46.  What does a Standard IP Access-list use as test criteria?
* IP source address
* IP source and destination address, protocol numbers and port numbers
* IPX source and destination address
* Source MAC address
Correct answer: A
Standard IP access list use only source address.
47.  What is the function of the Transport layer and which protocols reside there?
* MAC addressing - IP
* Interhost communication - SQL, NFS
* Best effort Packet delivery - TCP, UDP
* End-to-end connections - TCP, UDP
Correct answer: D
Layer 4, the Transport layer, is responsible for end-to-end connections. The two TCP/IP protocols that reside there are TCP and UDP.
48.  Identify the 3 Internet layer IP protocols?
* NetBios
* IP
Correct answer: C D E
NetBios and IPX are not layer 3 IP protocols. IP - Internet Protocol, ARP - Address Resolution Protocol and RARP - Reverse Address Resolution Protocol.
49.  IPX routing updates occur how often?
* Every 30 seconds
* Every 60 seconds
* Only as needed
* When the remote router asks for an update
Correct answer: B
IPX RIP updates are exchanged every 60 seconds.
50.  Identify 3 methods not used to prevent routing loops?
* Holddown timers
* Sequence numbers
* Triggered updates
* Split horizon
* Area hierarchies
* Order of router startup
Correct answer: B E F
Area hierarchies, sequence numbers and order of router startup all relate to Link State routing protocols which do NOT incur routing loops.
51.  Identify the hardware component that stores the bootstrap program?
* Booter load
* Flash
Correct answer: A
ROM contains the boot strap code.
52.  Which OSI layer provides mechanical, electrical, procedural for activating, maintaining physical link?
* Presentation
* Network
* Application
* Physical
* Transport
* Data-Link
Correct answer: D
Layer 1 the Physical layer performs this function.
53.  Identify 2 characteristics of PPP?
* Uses LLC to establish the link
* Default serial encapsulation
* Support multiple layer 3 protocols
* Offers two types of authentication; PAP and CHAP
Correct answer: C D
PPP is not the default encapsulation and uses LCP not LLC to establish the link. It support multiple layer 3 protocols and supports authentication.
54.  Identify 3 characteristics of a connection oriented protocol?
* Path determination
* Flow control
* Acknowledgements
* Uses hop count as metric
* 3 step handshake
Correct answer: B C E
Connection oriented protocols must first establish the connection (3 step handshake), employ methods to acknowledge the receipt of data (acknowledgements) and slow down the flow of data if required (flow control).
55.  What is the maximum hop count for IP RIP?
* Infinity
* 16
* 15
* 1
Correct answer: C
56.  is the maximum hop count, underscoring the size limitation of RIP.
57.  What is Cisco’s default encapsulation method on serial interfaces?
* Cisco
* Q933a
Correct answer: D
Cisco’s implementation of HDLC is only compatible with Cisco routers. It is the default encapsulation type for serial interfaces.
58.  Which of the following is a characteristic of a switch, but not of a repeater?
* Switches forward packets based on the IPX or IP address in the frame
* Switches forward packets based on the IP address in the frame
* Switches forward packets based on the MAC address in the frame
* Switches forward packets based only on the IP address in the packet
Correct answer: C
A repeater regenerates the signal it receives, a switch makes decisions based upon MAC addresses to determine whether a frame should be forwarded. Repeaters forward all packets.
59.  Ping uses which Internet layer protocol?
Correct answer: B
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.
60.  Which is true regarding store-and-forward switching method?
* Latency varies depending on frame-length
* Latency is constant
* It is default for all Cisco switches
* It only reads the destination hardware address before forwarding the frame
Correct answer: A
Store-and-Forward switching copies the entire frame into its buffer and computes the CRC. If a CRC error is detected, the frame is discarded, or if the frame is a runt (less than 64 bytes including the CRC) or a giant (more than 1518 bytes including the CRC). The LAN switch then looks up the destination address in its switching table and determines the outgoing interface. The frame is then forwarded to the outgoing interface. Cisco Catalyst 5000 switches uses the Store-and-Forward method. The problem with Store-and-Forward switching is latency is increased. Latency also varies with the size of the frame. The larger the frame, the more latency associated. This of course is due to the fact that the entire frame is copied into its buffer before being forwarded.
61.  Which three of the following are true statements about connection-oriented sessions?
* The segments delivered are acknowledged back to the sender upon their reception
* Any segments not acknowledged the are retransmitted by the receiver
* A manageable data flow is maintained in order to avoid congestion, overloading and loss of any data
* Segments are sequenced back into their proper order upon arrival at their destination
Correct answer: A C D
Connection-oriented services are useful for transmitting data from applications that are intolerant of delays and packet re-sequencing. FTP and Telnet applications are based on connection-oriented services as well as some voice and video programs. Any segment that is not acknowledged by the received is retransmitted by the sender.
62.  What does a metric of 16 hops represent when using RIP?
* Number of hops to the destination
* Destination unreachable
* Number of routers
* Bandwidth
Correct answer: B
Routing Information Protocol (RIP) is a distance vector routing protocol that used 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.
63.  You need to come up with a TCP/IP addressing scheme for your company. Which two factors must you consider when you define the subnet mask for the network?
* The location of DHCP servers
* The volume of traffic on each subnet
* The number of subnets on the network
* The location of the default gateway
* The number of host IDs on each subnet
Correct answer: C E
When determining which subnet mask to use, you must determine how many hosts and how many subnets are required.

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