Chapter 7 Cisco Exam Answers

What is the complete range of TCP and UDP well-known ports? 0 to 255 0 to 1023 256 - 1023 1024 - 49151

0 to 1023

A PC is downloading a large file from a server. The TCP window is 1000 bytes. The server is sending the file using 100-byte segments. How many segments will the server send before it requires an acknowledgment from the PC? 1 segment 10 segments 100 segments 1000 segments

10 segments

Which three IP addresses are private ? (Choose three.) 10.1.1.1 172.32.5.2 192.167.10.10 172.16.4.4 192.168.5.5 224.6.6.6

10.1.1.1 172.16.4.4 192.168.5.5 WHY? The private IP addresses are within these three ranges: 10.0.0.0 - 10.255.255.255 172.16.0.0 - 172.31.255.255 192.168.0.0 - 192.168.255.255

What is the binary equivalent of the decimal number 232? 11101000 11000110 10011000 11110010

11101000

The binary equivalent of the decimal number 232 is _______

11101000 WHY? To convert a decimal number to binary, first determine if the decimal number is equal to or greater than 128. In this case, because 232 is larger than 128, a 1 is placed in the bit position for decimal value 128 and the value of 128 is then subtracted from 232. This results in the value of 104. We then compare this value to 64. As 104 is larger than 64, a 1 is placed in the bit position for the decimal value 64 and the value of 64 is subtracted from 104. The remaining value is then 40. The process should be continued for all the remaining bit positions.​

What is the decimal equivalent of the binary number 10010101? 149 157 168 192

149

The decimal equivalent of the binary number 10010101 is ____

149 WHY? To convert a binary number to the decimal equivalent, add the value of the position where any binary 1 is present.

What subnet mask is represented by the slash notation /20? 255.255.255.248 255.255.224.0 255.255.240.0 255.255.255.0 255.255.255.192

255.255.240.0 WHY? The slash notation /20 represents a subnet mask with 20 1s. This would translate to: 11111111.11111111.11110000.0000, which in turn would convert into 255.255.240.0.

How many bits are in an IPv4 address? 32 64 128 256

32 WHY? An IPv4 address is comprised of 4 octets of binary digits, each containing 8 bits, resulting in a 32-bit address.

Which of these addresses is the shortest abbreviation for the IP address:3FFE:1044:0000:0000:00AB:0000:0000:0057? 3FFE:1044::AB::57 3FFE:1044::00AB::0057 3FFE:1044:0:0:AB::57 3FFE:1044:0:0:00AB::0057 3FFE:1044:0000:0000:00AB::57 3FFE:1044:0000:0000:00AB::0057

3FFE:1044:0:0:AB::57

A total of ___ messages are exchanged during the TCP session termination process between the client and the server.

4

What is the decimal equivalent of the hex number 0x3F?

63 WHY? To convert from hexadecimal to decimal, multiply each digit by the place value that is associated with the position of the digit and add the results.

What are three characteristics of multicast transmission? (Choose three.) The source address of a multicast transmission is in the range of 224.0.0.0 to 224.0.0.255. A single packet can be sent to a group of hosts. Multicast transmission can be used by routers to exchange routing information. The range of 224.0.0.0 to 224.0.0.255 is reserved to reach multicast groups on a local network. Computers use multicast transmission to request IPv4 addresses. Multicast messages map lower layer addresses to upper layer addresses.

A single packet can be sent to a group of hosts. Multicast transmission can be used by routers to exchange routing information. The range of 224.0.0.0 to 224.0.0.255 is reserved to reach multicast groups on a local network. WHY? Broadcast messages consist of single packets that are sent to all hosts on a network segment. These types of messages are used to request IPv4 addresses, and map upper layer addresses to lower layer addresses. A multicast transmission is a single packet sent to a group of hosts and is used by routing protocols, such as OSPF and RIPv2, to exchange routes. The address range 224.0.0.0 to 224.0.0.255 is reserved for link-local addresses to reach multicast groups on a local network.

Which scenario describes a function provided by the transport layer?' A student is using a classroom VoIP phone to call home. The unique identifier burned into the phone is a transport layer address used to contact another network device on the same network. A student is playing a short web-based movie with sound. The movie and sound are encoded within the transport layer header. A student has two web browser windows open in order to access two web sites. The transport layer ensures the correct web page is delivered to the correct browser window. A corporate worker is accessing a web server located on a corporate network. The transport layer formats the screen so the web page appears properly no matter what device is being used to view the web site.

A student has two web browser windows open in order to access two web sites. The transport layer ensures the correct web page is delivered to the correct browser window.

Which two flags in the TCP header are used in a TCP three-way handshake to establish connectivity between two network devices? (Choose two.) ACK FIN PSH RST SYN URG

ACK SYN

What field content is used by ICMPv6 to determine that a packet has expired? TTL field CRC field Hop Limit field Time Exceeded field

Hop Limit field WHY? ICMPv6 sends a Time Exceeded message if the router cannot forward an IPv6 packet because the packet expired. The router uses a hop limit field to determine if the packet has expired, and does not have a TTL field.

Which protocol supports Stateless Address Autoconfiguration (SLAAC) for dynamic assignment of IPv6 addresses to a host? ARPv6 DHCPv6 ICMPv6 UDP

ICMPv6 WHY? SLAAC uses ICMPv6 messages when dynamically assigning an IPv6 address to a host. DHCPv6 is an alternate method of assigning an IPv6 addresses to a host. ARPv6 does not exist. Neighbor Discovery Protocol (NDP) provides the functionality of ARP for IPv6 networks. UDP is the transport layer protocol used by DHCPv6.

What is indicated by a successful ping to the ::1 IPv6 address? The host is cabled properly. The default gateway address is correctly configured. All hosts on the local link are available. The link-local address is correctly configured. IP is properly installed on the host.

IP is properly installed on the host. WHY? The IPv6 address ::1 is the loopback address. A successful ping to this address means that the TCP/IP stack is correctly installed. It does not mean that any addresses are correctly configured.

What does a client do when it has UDP datagrams to send? It just sends the datagrams. It queries the server to see if it is ready to receive data. It sends a simplified three-way handshake to the server. It sends to the server a segment with the SYN flag set to synchronize the conversation.

It just sends the datagrams.

During a TCP session, the ___ flag is used by the client to request communication with the server.

SYN

Which transport layer feature is used to guarantee session establishment? UDP ACK flag TCP 3-way handshake UDP sequence number TCP port number

TCP 3-way handshake

What happens if the first packet of a TFTP transfer is lost? The client will wait indefinitely for the reply. The TFTP application will retry the request if a reply is not received. The next-hop router or the default gateway will provide a reply with an error code. The transport layer will retry the query if a reply is not received.

The TFTP application will retry the request if a reply is not received.

A technician wishes to use TFTP to transfer a large file from a file server to a remote router. Which statement is correct about this scenario? The file is segmented and then reassembled in the correct order by TCP. The file is segmented and then reassembled in the correct order at the destination, if necessary, by the upper-layer protocol. The file is not segmented, because UDP is the transport layer protocol that is used by TFTP. Large files must be sent by FTP not TFTP.

The file is segmented and then reassembled in the correct order at the destination, if necessary, by the upper-layer protocol.

What are three parts of an IPv6 global unicast address? (Choose three.) an interface ID that is used to identify the local network for a particular host a global routing prefix that is used to identify the network portion of the address that has been provided by an ISP a subnet ID that is used to identify networks inside of the local enterprise site a global routing prefix that is used to identify the portion of the network address provided by a local administrator an interface ID that is used to identify the local host on the network

a global routing prefix that is used to identify the network portion of the address that has been provided by an ISP a subnet ID that is used to identify networks inside of the local enterprise site an interface ID that is used to identify the local host on the network WHY? There are three elements that make up an IPv6 global unicast address. A global routing prefix which is provided by an ISP, a subnet ID which is determined by the organization, and an interface ID which uniquely identifies the interface interface of a host.

What does a client application select for a TCP or UDP source port number? a random value in the well-known port range a random value in the range of the registered ports a predefined value in the well-known port range a predefined value in the range of the registered ports

a random value in the range of the registered ports WHY? The client randomly selects an available source port in the range of the registered ports.

A host device sends a data packet to a web server via the HTTP protocol. What is used by the transport layer to pass the data stream to the proper application on the server? sequence number acknowledgment source port number destination port number

destination port number

A message is sent to all hosts on a remote network. Which type of message is it? limited broadcast multicast directed broadcast unicast

directed broadcast WHY? A directed broadcast is a message sent to all hosts on a specific network. It is useful for sending a broadcast to all hosts on a nonlocal network. A multicast message is a message sent to a selected group of hosts that are part of a subscribing multicast group. A limited broadcast is used for a communication that is limited to the hosts on the local network. A unicast message is a message sent from one host to another.

Which two IPv4 to IPv6 transition techniques manage the interconnection of IPv6 domains? (Choose two.) trunking dual stack encapsulation tunneling multiplexing

dual stack tunneling WHY? There are three techniques to allow IPv4 and IPv6 to co-exist on a network. Dual stack allows IPv4 and IPv6 to coexist on the same network segment. Dual stack devices run both IPv4 and IPv6 protocol stacks simultaneously. Tunneling is a method of transporting an IPv6 packet over an IPv4 network. The IPv6 packet is encapsulated inside an IPv4 packet, similar to other types of data. Network Address Translation 64 (NAT64) allows IPv6-enabled devices to communicate with IPv4-enabled devices using a translation technique similar to NAT for IPv4

What is a beneficial feature of the UDP transport protocol? What is a beneficial feature of the UDP transport protocol? acknowledgment of received data fewer delays in transmission tracking of data segments using sequence numbers the ability to retransmit lost data

fewer delays in transmission

What does the IP address 172.17.4.250/24 represent? network address multicast address host address broadcast address

host address WHY? The /24 shows that the network address is 172.17.4.0. The broadcast address for this network would be 172.17.4.255. Useable host addresses for this network are 172.17.4.1 through 172.17.4.254.

What type of address is automatically assigned to an interface when IPv6 is enabled on that interface? global unicast link-local loopback unique local

link-local WHY? When IPv6 is enabled on any interface, that interface will automatically generate an IPv6 link-local address.

What are two types of IPv6 unicast addresses? (Choose two.) multicast loopback link-local anycast broadcast

loopback link-local WHY? Multicast, anycast, and unicast are types of IPv6 addresses. There is no broadcast address in IPv6. Loopback and link-local are specific types of unicast addresses.

A host device needs to send a large video file across the network while providing data communication to other users. Which feature will allow different communication streams to occur at the same time, without having a single data stream using all available bandwidth? window size multiplexing port numbers acknowledgments

multiplexing

Which two parts are components of an IPv4 address? (Choose two.) subnet portion network portion logical portion host portion physical portion broadcast portion

network portion host portion WHY? An IPv4 address is divided into two parts: a network portion - to identify the specific network on which a host resides, and a host portion - to identify specific hosts on a network. A subnet mask is used to identify the length of each portion.

Compared to UDP, what factor causes additional network overhead for TCP communication? network traffic that is caused by retransmissions the identification of applications based on destination port numbers the encapsulation into IP packets the checksum error detection

network traffic that is caused by retransmissions

Which two TCP header fields are used to confirm receipt of data? FIN flag SYN flag checksum sequence number acknowledgment number

sequence number acknowledgment number WHY? Together the TCP sequence number and acknowledgment number fields are used by the receiver to inform the sender of the bytes of data that the receiver has accepted.

An administrator wants to configure hosts to automatically assign IPv6 addresses to themselves by the use of Router Advertisement messages, but also to obtain the DNS server address from a DHCPv6 server. Which address assignment method should be configured? SLAAC stateless DHCPv6 stateful DHCPv6 RA and EUI-64

stateless DHCPv6 WHY? Stateless DHCPv6 allows clients to use ICMPv6 Router Advertisement (RA) messages to automatically assign IPv6 addresses to themselves, but then allows these clients to contact a DHCPv6 server to obtain additional information such as the domain name and address of DNS servers. SLAAC does not allow the client to obtain additional information through DHCPv6, and stateful DHCPv6 requires that the client receive its interface address directly from a DHCPv6 server. RA messages, when combined with an EUI-64 interface identifier, are used to automatically create an interface IPv6 address, and are part of both SLAAC and stateless DHCPv6.

Which factor determines TCP window size? the amount of data to be transmitted the number of services included in the TCP segment the amount of data the destination can process at one time the amount of data the source is capable of sending at one time

the amount of data the destination can process at one time

Which two things can be determined by using the ping command? (Choose two.) the number of routers between the source and destination device the IP address of the router nearest the destination device the average time it takes a packet to reach the destination and for the response to return to the source the destination device is reachable through the network the average time it takes each router in the path between source and destination to respond

the average time it takes a packet to reach the destination and for the response to return to the source the destination device is reachable through the network WHY? A ping command provides feedback on the time between when an echo request was sent to a remote host and when the echo reply was received. This can be a measure of network performance. A successful ping also indicates that the destination host was reachable through the network.

What is a socket? the combination of the source and destination IP address and source and destination Ethernet address the combination of a source IP address and port number or a destination IP address and port number the combination of the source and destination sequence and acknowledgment numbers the combination of the source and destination sequence numbers and port numbers

the combination of a source IP address and port number or a destination IP address and port number

During a TCP session, a destination device sends an acknowledgment number to the source device. What does the acknowledgment number represent? the total number of bytes that have been received one number more than the sequence number the next byte that the destination expects to receive the last sequence number that was sent by the source

the next byte that the destination expects to receive WHY? The window size determines the number of bytes that will be sent before expecting an acknowledgement. The acknowledgement number is the number of the next expected byte. For example, if a host has received 3140 bytes, the host would respond with an acknowledgement number of 3141.

What is the purpose of the subnet mask in conjunction with an IP address? to uniquely identify a host on a network to identify whether the address is public or private to determine the subnet to which the host belongs to mask the IP address to outsiders

to determine the subnet to which the host belongs WHY? With the IPv4 address, a subnet mask is also necessary. A subnet mask is a special type of IPv4 address that coupled with the IP address determines the subnet of which the device is a member.

What is the purpose of ICMP messages? to inform routers about network topology changes to ensure the delivery of an IP packet to provide feedback of IP packet transmissions to monitor the process of a domain name to IP address resolution

to provide feedback of IP packet transmissions WHY? The purpose of ICMP messages is to provide feedback about issues that are related to the processing of IP packets.

A user is executing a tracert to a remote device. At what point would a router, which is in the path to the destination device, stop forwarding the packet? when the router receives an ICMP Time Exceeded message when the RTT value reaches zero when the host responds with an ICMP Echo Reply message when the value in the TTL field reaches zero when the values of both the Echo Request and Echo Reply messages reach zero

when the value in the TTL field reaches zero WHY? When a router receives a traceroute packet, the value in the TTL field is decremented by 1. When the value in the field reaches zero, the receiving router will not forward the packet, and will send an ICMP Time Exceeded message back to the source.