CCNA 1 v7 Modules 14 - 15: Network Application Communications Exam Answers
CCNA 1 v7 Modules 14 - 15: Network Application Communications Exam Answers
CCNA 1 v7 Modules 14 - 15: Network Application Communications Exam Answers
11. What important information is added to the TCP/IP transport layer header
to ensure communication and connectivity with a remote network device?
timing and synchronization
destination and source port numbers
destination and source physical addresses
destination and source logical network addresses
12. Which two characteristics are associated with UDP sessions? (Choose two.)
Destination devices receive traffic with minimal delay.
Transmitted data segments are tracked.
Destination devices reassemble messages and pass them to an
application.
Received data is unacknowledged.
Unacknowledged data packets are retransmitted.
Explanation:
TCP:
Provides tracking of transmitted data segments
Destination devices will acknowledge received data.
Source devices will retransmit unacknowledged data.
UDP
Destination devices will not acknowledge received data
Headers use very little overhead and cause minimal delay.
14. Which flag in the TCP header is used in response to a received FIN in order
to terminate connectivity between two network devices?
FIN
ACK
SYN
RST
Explanation: In a TCP session, when a device has no more data to send, it
will send a segment with the FIN flag set. The connected device that receives
the segment will respond with an ACK to acknowledge that segment. The
device that sent the ACK will then send a FIN message to close the
connection it has with the other device. The sending of the FIN should be
followed with the receipt of an ACK from the other device.
15. Which protocol or service uses UDP for a client-to-server communication and
TCP for server-to-server communication?
HTTP
FTP
DNS
SMTP
Explanation: Some applications may use both TCP and UDP. DNS uses UDP
when clients send requests to a DNS server, and TCP when two DNS serves
directly communicate.
16. What is a characteristic of UDP?
UDP datagrams take the same path and arrive in the correct order at
the destination.
Applications that use UDP are always considered unreliable.
UDP reassembles the received datagrams in the order they were received.
UDP only passes data to the network when the destination is ready to
receive the data.
Explanation: UDP has no way to reorder the datagrams into their transmission
order, so UDP simply reassembles the data in the order it was received and
forwards it to the application.
17. What kind of port must be requested from IANA in order to be used with a
specific application?
registered port
private port
dynamic port
source port
Explanation: Registered ports (numbers 1024 to 49151) are assigned by IANA
to a requesting entity to use with specific processes or applications. These
processes are primarily individual applications that a user has chosen to
install, rather than common applications that would receive a well-known port
number. For example, Cisco has registered port 1985 for its Hot Standby
Routing Protocol (HSRP) process.
18. Which three application layer protocols use TCP? (Choose three.)
SMTP
FTP
SNMP
HTTP
TFTP
DHCP
Explanation: Some protocols require the reliable data transport that is
provided by TCP. In addition, these protocols do not have real time
communication requirements and can tolerate some data loss while
minimizing protocol overhead. Examples of these protocols are SMTP, FTP,
and HTTP.
19. Which three statements characterize UDP? (Choose three.)
UDP provides basic connectionless transport layer functions.
UDP provides connection-oriented, fast transport of data at Layer 3.
UDP relies on application layer protocols for error detection.
UDP is a low overhead protocol that does not provide sequencing or flow
control mechanisms.
UDP relies on IP for error detection and recovery.
UDP provides sophisticated flow control mechanisms.
Explanation: UDP is a simple protocol that provides the basic transport layer
functions. It has much lower overhead than TCP because it is not connection-
oriented and does not offer the sophisticated retransmission, sequencing, and
flow control mechanisms that provide reliability.
20. Which two fields are included in the TCP header but not in the UDP header?
(Choose two.)
window
checksum
source port
destination port
sequence number
Explanation: The sequence number and window fields are included in the
TCP header but not in the UDP header.
21. Which field in the TCP header indicates the status of the three-way
handshake process?
window
reserved
checksum
control bits
Explanation: The value in the control bits field of theTCP header indicates the
progress and status of the connection.
22. Why does HTTP use TCP as the transport layer protocol?
to ensure the fastest possible download speed
because HTTP is a best-effort protocol
because transmission errors can be tolerated easily
because HTTP requires reliable delivery
Explanation: When a host requests a web page, transmission reliability and
completeness must be guaranteed. Therefore, HTTP uses TCP as its
transport layer protocol.
23. Which two types of applications are best suited for UDP? (Choose two.)
applications that need data flow control
applications that require reliable delivery
applications that handle reliability themselves
applications that need the reordering of segments
applications that can tolerate some data loss, but require little or no delay
24. How are port numbers used in the TCP/IP encapsulation process?
Source port numbers and destination port numbers are not necessary
when UDP is the transport layer protocol being used for the
communication.
Source port and destination port numbers are randomly generated.
If multiple conversations occur that are using the same service, the source
port number is used to track the separate conversations.
Destination port numbers are assigned automatically and cannot be
changed.
Explanation: Both UDP and TCP use port numbers to provide a unique
identifier for each conversation. Source port numbers are randomly generated
and are used to track different conversations. Destination port numbers
identify specific services by using either a default port number for the service
or a port number that is assigned manually by a system administrator.
25. In what two situations would UDP be better than TCP as the preferred
transport protocol? (Choose two.)
when applications need to guarantee that a packet arrives intact, in
sequence, and unduplicated
when a faster delivery mechanism is needed
when delivery overhead is not an issue
when applications do not need to guarantee delivery of the data
when destination port numbers are dynamic
Explanation: UDP is a very simple transport layer protocol that does not
guarantee delivery. Devices on both ends of the conversation are not required
to keep track of the conversation. UDP is used as the transport protocol for
applications that need a speedy, best-effort delivery.
26. What are three responsibilities of the transport layer? (Choose three.)
meeting the reliability requirements of applications, if any
multiplexing multiple communication streams from many users or
applications on the same network
identifying the applications and services on the client and server that
should handle transmitted data
directing packets towards the destination network
formatting data into a compatible form for receipt by the destination
devices
conducting error detection of the contents in frames
Explanation: The transport layer has several responsibilities. Some of the
primary responsibilities include the following:
Tracking the individual communication streams between applications on the
source and destination hosts
Segmenting data at the source and reassembling the data at the destination
Identifying the proper application for each communication stream through the
use of port numbers
Multiplexing the communications of multiple users or applications over a single
network
Managing the reliability requirements of applications
27. Which three statements describe a DHCP Discover message? (Choose three.)
The source MAC address is 48 ones (FF-FF-FF-FF-FF-FF).
The destination IP address is 255.255.255.255.
The message comes from a server offering an IP address.
The message comes from a client seeking an IP address.
All hosts receive the message, but only a DHCP server replies.
Only the DHCP server receives the message.
Explanation: When a host configured to use DHCP powers up on a network it
sends a DHCPDISCOVER message. FF-FF-FF-FF-FF-FF is the L2 broadcast
address. A DHCP server replies with a unicast DHCPOFFER message back
to the host.
28. Which two protocols may devices use in the application process that sends
email? (Choose two.)
HTTP
SMTP
POP
IMAP
DNS
POP3
Explanation: POP, POP3, and IMAP are protocols that are used to retrieve
email from servers. SMTP is the default protocol that is used to send email.
DNS may be used by the sender email server to find the address of the
destination email server.
29. What is true about the Server Message Block protocol?
Different SMB message types have a different format.
Clients establish a long term connection to servers.
SMB messages cannot authenticate a session.
SMB uses the FTP protocol for communication.
Explanation: The Server Message Block protocol is a protocol for file, printer,
and directory sharing. Clients establish a long term connection to servers and
when the connection is active, the resources can be accessed. Every SMB
message has the same format. The use of SMB differs from FTP mainly in the
length of the sessions. SMB messages can authenticate sessions.
30. What is the function of the HTTP GET message?
to request an HTML page from a web server
to send error information from a web server to a web client
to upload content to a web server from a web client
to retrieve client email from an email server using TCP port 110
31. Which OSI layer provides the interface between the applications used to
communicate and the underlying network over which messages are transmitted?
application
presentation
session
transport
32. Which networking model is being used when an author uploads one chapter
document to a file server of a book publisher?
peer-to-peer
master-slave
client/server
point-to-point
Explanation: In the client/server network model, a network device assumes
the role of server in order to provide a particular service such as file transfer
and storage. In the client/server network model, a dedicated server does not
have to be used, but if one is present, the network model being used is the
client/server model. In contrast, a peer-to-peer network does not have a
dedicated server.
33. What do the client/server and peer-to-peer network models have in common?
Both models have dedicated servers.
Both models support devices in server and client roles.
Both models require the use of TCP/IP-based protocols.
Both models are used only in the wired network environment.
Explanation: In both the client/server and peer-to-peer network models, clients
and servers exist. In peer-to-peer networks, no dedicated server exists, but a
device can assume the server role to provide information to a device serving
in the client role.
34. In what networking model would eDonkey, eMule, BitTorrent, Bitcoin, and
LionShare be used?
peer-to-peer
client-based
master-slave
point-to-point
Explanation: In a peer-to-peer networking model, data is exchanged between
two network devices without the use of a dedicated server. Peer-to-peer
applications such as Shareaz, eDonkey, and Bitcoin allow one network device
to assume the role of server, while one or more other network devices assume
the role of client using the peer-to-peer application.
35. What is a common protocol that is used with peer-to-peer applications such
as WireShare, Bearshare, and Shareaza?
Ethernet
Gnutella
POP
SMTP
Explanation: The Gnutella protocol is used when one user shares an entire file
with another user. A person would load a Gnutella-based application such as
gtk-gnutella or WireShare and use that application to locate and access
resources shared by others.
42. Which application layer protocol uses message types such as GET, PUT, and
POST?
DNS
DHCP
SMTP
HTTP
POP3
Explanation: The GET command is a client request for data from a web
server. A PUT command uploads resources and content, such as images, to a
web server. A POST command uploads data files to a web server.
43. What type of information is contained in a DNS MX record?
the FQDN of the alias used to identify a service
the IP address for an FQDN entry
the domain name mapped to mail exchange servers
the IP address of an authoritative name server
Explanation: MX, or mail exchange messages, are used to map a domain
name to several mail exchange servers that all belong to the same domain.
44. Which three protocols operate at the application layer of the TCP/IP model?
(Choose three.)
ARP
TCP
UDP
FTP
POP3
DHCP
Explanation: FTP, DHCP, and POP3 are application layer protocols. TCP and
UDP are transport layer protocols. ARP is a network layer protocol.
45. Which protocol is used by a client to communicate securely with a web
server?
SMTP
SMB
IMAP
HTTPS
Explanation: HTTPS is a secure form of HTTP used to access web content
hosted by a web server.
46. Which applications or services allow hosts to act as client and server at the
same time?
client/server applications
email applications
P2P applications
authentication services
Explanation: P2P applications allow the clients to behave as servers if
needed. When using authentication services, email exchange, and
client/server applications, one host acts as server and the other acts as client
at all times.