Ccna certification Practice Tests

413

 73.  B.  Delay is the time it takes for a packet to travel from source to destination, which is 

a description of one-way delay. Round-trip delay is the time it takes for the packet to 

travel from source to destination (one-way delay) plus the time it takes for the destination 

computer to send the packet back to the originating node to form a round trip. Bandwidth 

is the measured maximum of throughput for a connection. Jitter is the difference between 

the delay of packets. Loss is the measurement of packets lost in the transfer of data.

 74.  A.  The Differentiated Services Code Point (DSCP) is a 6-bit value in the Type of Service 

(ToS) field of the IP header. The DSCP value defines the importance of packets at layer 3. 

802.1Q is a layer 2 trunking protocol that accommodates CoS markings. Class of Service 

(CoS) is a 3-bit field in an 802.1Q Ethernet frame. QoE is not a valid term used with 

Ethernet and therefore is an invalid answer.

 75.  C.  The command 

username scpadmin privilege-level 15 password Sybex must 

be configured. This command will configure a user named scpadmin with a privilege level 

of 15 (enable access) and a password of Sybex. The command 

ip scp user scpadmin 

password Sybex is incorrect. The command username scpadmin password Sybex 

is incorrect. The command 

ip scp user scpadmin privilege-level 15 password 

Sybex is incorrect.

 76.  D.  An attacker will take advantage of the automatic trunking configuration of Dynamic 

Trunking Protocol (DTP). This will allow the attacker to create a trunk with the switch 

and tag packets so that they can hop onto different VLANs. An open Telnet connection 

can be eavesdropped on since it is in clear text. Automatic encapsulation negotiation 

is not a valid term used with switching; therefore, it is an invalid answer. Forwarding 

of broadcasts is not really an exploit; it is a function of switching. Routers will stop the 

forwarding of broadcasts.

 77.  C.  Port security can prevent MAC address flooding attacks by restricting the number 

of MAC addresses associated to an interface. This will prevent the Content Addressable 

Memory (CAM) from being overrun by bogus entries. Access control lists (ACLs) will 

allow you to control layer 3 and layer 4 network traffic but are not used to prevent MAC 

address flooding attacks. Network Address Translation (NAT) is also not used to prevent 

MAC address flooding attacks. VLAN access control lists (VACLs) can be used to control 

layer 2, 3, and 4 traffic, but they are not used to prevent MAC address flooding attacks.

 78.  A.  Locking doors is a recommended physical security method. Installing antivirus 

software is a form of digital protection. Firewalls are considered logical security. 

Directory-level permissions are considered a form of logical security.

 79.  C.  The command 

logging synchronous will configure console logging messages 

to synchronize with what is being typed so they will not disrupt the user’s input. The 

command must be configured for the line that it will be applied to. The command 

no 

logging inline is incorrect. The command logging synchronous is incorrect when 

configured from a global configuration prompt. The command 

logging synchronous is 

incorrect when configured from a privileged exec prompt.

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