Networking Questions: Network Application Communications
A client creates a packet to send to a server. The client is requesting FTP service. What number will be used as the destination port number in the sending packet?
21
Which three protocols or standards are used at the application layer of the TCP/IP model?
MPEG; HTTP; GIF
Which applications or services allow hosts to act as client and server at the same time?
P2P applications
What is a characteristic of UDP?
UDP reassembles the received datagrams in the order they were received.
Which two services or protocols use the preferred UDP protocol for fast transmission and low overhead?
VoIP
On a home network, which device is most likely to provide dynamic IPv4 addressing to clients on the home network?
a home router
Which OSI layer provides the interface between the applications used to communicate and the underlying network over which messages are transmitted?
application
Which layer in the TCP/IP model is used for formatting, compressing, and encrypting data?
application
Which two types of applications are best suited for UDP?
applications that handle reliability themselves; applications that can tolerate some data loss, but require little or no delay
What part of the URL, ht​tp://ww​w.cisco.com/index.html, represents the top-level DNS domain?
.com
What is the complete range of TCP and UDP well-known ports?
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?
10 segments
A client creates a packet to send to a server. The client is requesting TFTP service. What number will be used as the destination port number in the sending packet?
69
Assume a host with IP address 10.1.1.10 wants to request web services from a server at 10.1.1.254. Which of the following would display the correct socket pair?
10.1.1.10:1099, 10.1.1.254:80
A client creates a packet to send to a server. The client is requesting POP3 service. What number will be used as the destination port number in the sending packet?
110
Which number or set of numbers represents a socket?
192.168.1.1:80
A client creates a packet to send to a server. The client is requesting SSH service. What number will be used as the destination port number in the sending packet?
22
A client creates a packet to send to a server. The client is requesting telnet service. What number will be used as the destination port number in the sending packet?
23
A client creates a packet to send to a server. The client is requesting HTTPS service. What number will be used as the destination port number in the sending packet?
443
A PC that is communicating with a web server has a TCP window size of 6,000 bytes when sending data and a packet size of 1,500 bytes. Which byte of information will the web server acknowledge after it has received three packets of data from the PC?
4501
A client creates a packet to send to a server. The client is requesting HTTP service. What number will be used as the destination port number in the sending packet?
80
What is an example of network communication that uses the client-server model?
A workstation initiates a DNS request when the user types www.cisco.com in the address bar of a web browser.
Which flag in the TCP header is used in response to a received FIN in order to terminate connectivity between two network devices?
ACK
Which two flags in the TCP header are used in a TCP three-way handshake to establish connectivity between two network devices?
ACK and SYN
Which TCP/IP model layer is closest to the end user?
Application
What do the client/server and peer-to-peer network models have in common?
Both models support devices in server and client roles.
What is the termination process steps in the order?
Client sends FIN; Server sends ACK; Server sends FIN; Client sends ACK
What is true about the Server Message Block protocol?
Clients establish a long term connection to servers.
A wireless host needs to request an IPv4 address. What protocol would be used to process the request?
DHCP
Which protocol or service uses UDP for a client-to-server communication and TCP for server-to-server communication?
DNS
Which two characteristics are associated with UDP sessions?
Destination devices receive traffic with minimal delay; Received data is unacknowledged
A manufacturing company subscribes to certain hosted services from its ISP. The services that are required include hosted world wide web, file transfer, and e-mail. Which protocols represent these three key applications?
FTP; HTTP; SMTP
Which three protocols operate at the application layer of the TCP/IP model?
FTP; POP3; DHCP
What message type is used by an HTTP client to request data from a web server?
GET
What is a common protocol that is used with peer-to-peer applications such as WireShare, Bearshare, and Shareaza?
Gnutella
Which application layer protocol uses message types such as GET, PUT, and POST?
HTTP
Which protocol is used by a client to communicate securely with a web server?
HTTPS
Which protocol uses encryption?
HTTPS
When retrieving email messages, which protocol allows for easy, centralized storage and backup of emails that would be desirable for a small- to medium-sized business?
IMAP
How are port numbers used in the TCP/IP encapsulation process?
If multiple conversations occur that are using the same service, the source port number is used to track the separate conversations.
Why is DHCP for IPv4 preferred for use on large networks
It is a more efficient way to manage IPv4 addresses than static address assignment is.
What does a client do when it has UDP datagrams to send?
It just sends the datagrams.
Which protocol can be used to transfer messages from an email server to an email client?
POP3
Which application layer protocol is used to provide file-sharing and print services to Microsoft applications?
SMB
What is an advantage of SMB over FTP?
SMB clients can establish a long-term connection to the server.
Which two protocols may devices use in the application process that sends email?
SMTP and DNS
Which three application layer protocols use TCP?
SMTP, FTP, and HTTP
Which are the fields in a UDP segment header?
Source Port, Destination Port, Length, and Checksum fields
Which transport layer feature is used to guarantee session establishment?
TCP 3-way handshake
Which action is performed by a client when establishing communication with a server via the use of UDP at the transport layer?
The client randomly selects a source port number.
Which three statements describe a DHCP Discover message?
The destination IP address is 255.255.255.255; The message comes from a client seeking an IP address; All hosts receive the message, but only a DHCP server replies
What happens if part of an FTP message is not delivered to the destination?
The part of the FTP message that was lost is re-sent
Which two fields are included in the TCP header but not in the UDP header?
The sequence number and window fields
Network congestion has resulted in the source learning of the loss of TCP segments that were sent to the destination. What is one way that the TCP protocol addresses this?
The source decreases the amount of data that it transmits before it receives an acknowledgement from the destination.
An author is uploading one chapter document from a personal computer to a file server of a book publisher. What role is the personal computer assuming in this network model?
client
Which networking model is being used when an author uploads one chapter document to a file server of a book publisher?
client/server
Which field in the TCP header indicates the status of the three-way handshake process?
control bits
What are two characteristics of peer-to-peer networks?
decentralized resources; resource sharing without a dedicated server
What important information is added to the TCP/IP transport layer header to ensure communication and connectivity with a remote network device?
destination and source port numbers
What are three responsibilities of the transport layer?
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
In what networking model would eDonkey, eMule, BitTorrent, Bitcoin, and LionShare be used?
peer-to-peer
What kind of port must be requested from IANA in order to be used with a specific application?
registered port
What is a key characteristic of the peer-to-peer networking model?
resource sharing without a dedicated server
The application layer of the TCP/IP model performs the functions of what three layers of the OSI model?
session; presentation; application
What TCP mechanism is used to enhance performance by allowing a device to continuously send a steady stream of segments as long as the device is also receiving necessary acknowledgements?
sliding window
Which factor determines TCP window size?
the amount of data the destination can process at one time
What is a socket?
the combination of a source IP address and port number or a destination IP address and port number
What are two characteristics of the application layer of the TCP/IP model?
the creation and maintenance of dialogue between source and destination applications; closest to the end user
What is the function of the HTTP GET message?
to request an HTML page from a web server
In what two situations would UDP be better than TCP as the preferred transport protocol?
when a faster delivery mechanism is needed; when applications do not need to guarantee delivery of the data
Which statement is true about FTP?
The client can download data from or upload data to the server
What are the primary responsibilities of the transport layer in data communication on a network?
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, and identifying the proper application for each communication stream through the use of port numbers.
Which three statements characterize UDP?
UDP provides basic connectionless transport layer functions; UDP relies on application layer protocols for error detection; UDP relies on application layer protocols for error detection.
A PC that is communicating with a web server has a TCP window size of 6,000 bytes when sending data and a packet size of 1,500 bytes. Which byte of information will the web server acknowledge after it has received four packets of data from the PC?
6001
A client creates a packet to send to a server. The client is requesting SNMP service. What number will be used as the destination port number in the sending packet?
161
A client creates a packet to send to a server. The client is requesting SMTP service. What number will be used as the destination port number in the sending packet?
25
A PC that is communicating with a web server has a TCP window size of 6,000 bytes when sending data and a packet size of 1,500 bytes. Which byte of information will the web server acknowledge after it has received two packets of data from the PC?
3001
Which scenario describes a function provided by the transport layer?
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.
Why does HTTP use TCP as the transport layer protocol?
because HTTP requires reliable delivery
Which two tasks can be performed by a local DNS server?
mapping name-to-IP addresses for internal hosts; forward name resolution requests between servers
Which two operations are provided by TCP but not by UDP?
retransmitting any unacknowledged data; acknowledging received data
What information is used by TCP to reassemble and reorder received segments?
sequence numbers
What type of information is contained in a DNS MX record?
the domain name mapped to mail exchange servers
What is a responsibility of transport layer protocols?
tracking individual conversations
