ITN 82-119

82. What method is used to manage contention-based access on a wireless network?

• token passing

• • CSMA/CA

• • priority ordering

• • CSMA/CD

83. What is a function of the data link layer?

• • provides the formatting of data

• • provides end-to-end delivery of data between hosts

• • provides delivery of data between two applications

• • provides for the exchange of frames over a common local media

84. What is the purpose of the TCP sliding window?

• to ensure that segments arrive in order at the destination

• to end communication when data transmission is complete

• to inform a source to retransmit data from a specific point forward

• to request that a source decrease the rate at which it transmits data

Answer explanation

Explanation: The TCP sliding window allows a destination device to inform a source to slow down the rate of transmission. To do this, the destination device reduces the value contained in the window field of the segment. It is acknowledgment numbers that are used to specify retransmission from a specific point forward. It is sequence numbers that are used to ensure segments arrive in order. Finally, it is a FIN control bit that is used to end a communication session.

85. What characteristic describes spyware?

• a network device that filters access and traffic coming into a network

• software that is installed on a user device and collects information about the user

• • an attack that slows or crashes a device or network service

• the use of stolen credentials to access private data

86. Which switching method drops frames that fail the FCS check?

• store-and-forward switching

• borderless switching

• ingress port buffering

• cut-through switching

87. Which range of link-local addresses can be assigned to an IPv6-enabled interface?

• FEC0::/10

• FDEE::/7

• FE80::/10

• FF00::/8

Answer explanation

Explain:
Link-local addresses are in the range of FE80::/10 to FEBF::/10. The original IPv6 specification defined site-local addresses and used the prefix range FEC0::/10, but these addresses were deprecated by the IETF in favor of unique local addresses. FDEE::/7 is a unique local address because it is in the range of FC00::/7 to FDFF::/7. IPv6 multicast addresses have the prefix FF00::/8.

88. What service is provided by FTP?

• A basic set of rules for exchanging text, graphic images, sound, video, and other multimedia files on the web.

• An application that allows real-time chatting among remote users.

• Allows for data transfers between a client and a file server.

• Uses encryption to secure the exchange of text, graphic images, sound, and video on the web.

89. A user is attempting to access http://www.cisco.com/ without success. Which two configuration values must be set on the host to allow this access? (Choose two.)

• DNS server

• • source port number

• • HTTP server

• • source MAC address

• default gateway

90. Which two statements accurately describe an advantage or a disadvantage when deploying NAT for IPv4 in a network? (Choose two.)

• • NAT adds authentication capability to IPv4.

• NAT introduces problems for some applications that require end-to-end connectivity.

• NAT will impact negatively on switch performance.

• NAT provides a solution to slow down the IPv4 address depletion.

• NAT improves packet handling.

Answer explanation

Explanation: Network Address Translation (NAT) is a technology that is implemented within IPv4 networks. One application of NAT is to use private IP addresses inside a network and use NAT to share a few public IP addresses for many internal hosts. In this way it provides a solution to slow down the IPv4 address depletion. However, since NAT hides the actual IP addresses that are used by end devices, it may cause problems for some applications that require end-to-end connectivity.

91. What would be the interface ID of an IPv6 enabled interface with a MAC address of 1C-6F-65-C2-BD-F8 when the interface ID is generated by using the EUI-64 process?

• • 0C6F:65FF:FEC2:BDF8

• 1E6F:65FF:FEC2:BDF8

• • C16F:65FF:FEC2:BDF8

• • 106F:65FF:FEC2:BDF8

Answer explanation

Explanation: To derive the EUI-64 interface ID by using the MAC address 1C-6F-65-C2-BD-F8, three steps are taken.

• Change the seventh bit of the MAC address from a binary 0 to a binary 1 which changes the hex C, into a hex E.

• Insert hex digits FFFE into the middle of the address.

• Rewrite the address in IPv6 format.

The three steps, when complete, give the interface ID of 1E6F:65FF:FEC2:BDF8.