Network III.

Which two statements are correct in a comparison of IPv4 and IPv6 packet headers? (Choose two.)

• The Source Address field name from IPv4 is kept in IPv6.

• The Version field from IPv4 is not kept in IPv6.

• The Destination Address field is new in IPv6.

• The Header Checksum field name from IPv4 is kept in IPv6.

• The Time-to-Live field from IPv4 has been replaced by the Hop Limit field in IPv6.

Answer explanation

The IPv6 packet header fields are as follows: Version, Traffic Class, Flow Label, Payload Length, Next Header, Hop Limit, Source Address, and Destination Address. The IPv4 packet header fields include the following: Version, Differentiated Services, Time-to-Live, Protocol, Source IP Address, and Destination IP Address. Both versions have a 4-bit Version field. Both versions have a Source (IP) Address field. IPv4 addresses are 32 bits; IPv6 addresses are 128 bits. The Time-to-Live or TTL field in IPv4 is now called Hop Limit in IPv6, but this field serves the same purpose in both versions. The value in this 8-bit field decrements each time a packet passes through any router. When this value is 0, the packet is discarded and is not forwarded to any other router.

A network administrator wants to have the same network mask for all networks at a particular small site. The site has the following networks and number of devices:
IP phones – 22 addresses
PCs – 20 addresses needed
Printers – 2 addresses needed
Scanners – 2 addresses needed

The network administrator has deemed that 192.168.10.0/24 is to be the network used at this site. Which single subnet mask would make the most efficient use of the available addresses to use for the four subnetworks?

• 255.255.255.192

• 255.255.255.252

• 255.255.255.240

• 255.255.255.0

• 255.255.255.224

What characteristic describes identity theft?

• the use of stolen credentials to access private data

• software on a router that filters traffic based on IP addresses or applications

• software that identifies fast-spreading threats

• a tunneling protocol that provides remote users with secure access into the network of an organization

A network administrator is adding a new LAN to a branch office. The new LAN must support 200 connected devices. What is the smallest network mask that the network administrator can use for the new network?

• 255.255.255.240

• 255.255.255.0

• 255.255.255.248

• 255.255.255.224

What are three commonly followed standards for constructing and installing cabling? (Choose three.)

• cost per meter (foot)

• cable lengths

• connector color

• pinouts

• connector types

Refer to the exhibit. What is wrong with the displayed termination?

• The woven copper braid should not have been removed.

• The wrong type of connector is being used.

• The untwisted length of each wire is too long.

• The wires are too thick for the connector that is used.

Answer explanation

When a cable to an RJ-45 connector is terminated, it is important to ensure that the untwisted wires are not too long and that the flexible plastic sheath surrounding the wires is crimped down and not the bare wires. None of the colored wires should be visible from the bottom of the jack.

A client packet is received by a server. The packet has a destination port number of 143. What service is the client requesting?

• IMAP

• FTP

• SSH

• Telnet

What are two characteristics shared by TCP and UDP? (Choose two.)

• default window size

• connectionless communication

• port numbering

• ability to to carry digitized voice

• use of checksum

Answer explanation

Both TCP and UDP use source and destination port numbers to distinguish different data streams and to forward the right data segments to the right applications. Error checking the header and data is done by both protocols by using a checksum calculation to determine the integrity of the data that is received. TCP is connection-oriented and uses a 3-way handshake to establish an initial connection. TCP also uses window to regulate the amount of traffic sent before receiving an acknowledgment. UDP is connectionless and is the best protocol for carry digitized VoIP signals.

Refer to the exhibit. Which two network addresses can be assigned to the network containing 10 hosts? Your answers should waste the fewest addresses, not reuse addresses that are already assigned, and stay within the 10.18.10.0/24 range of addresses. (Choose two.)

• 10.18.10.200/28

• 10.18.10.208/28

• 10.18.10.240/27

• 10.18.10.200/27

• 10.18.10.224/28

Answer explanation

Addresses 10.18.10.0 through 10.18.10.63 are taken for the leftmost network. Addresses 192 through 199 are used by the center network. Because 4 host bits are needed to accommodate 10 hosts, a /28 mask is needed. 10.18.10.200/28 is not a valid network number. Two subnets that can be used are 10.18.10.208/28 and 10.18.10.224/28.

A client packet is received by a server. The packet has a destination port number of 21. What service is the client requesting?

• FTP

• LDAP

• SLP

• SNMP