Module 14 Test Questions

What is the range of registered ports and how do you get a registered port number?

1,024 to 49,151: these port numbers are assigned by IANA to a requesting entity to use with specific processes or applications (pg. 30)

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 (pg. 49)

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

Because HTTP requires reliable delivery (pg. 12)

A client application needs to terminate a TCP communications session with a server. What is the 4th step in the termination process? Client sends ACK Client sends FIN Client sends SYN Server sends ACK Server sends FIN Server sends SYN

Client sends ACK. (pg. 38)

A client application needs to terminate a TCP communications session with a server. What is the 1st step in the termination process? Client sends ACK Client sends FIN Client sends SYN Server sends ACK Server sends FIN Server sends SYN

Client sends FIN (pg. 38)

What is the application for port number 21?

File Transfer Protocol (FTP) - control (pg. 31)

What is the application for port number 20?

File Transfer Protocol (FTP) - data (pg. 31)

What is the application for port number 80?

Hypertext Transfer Protocol (HTTP) (pg. 31)

What are 3 responsibilities of the transport layer?

Identifies apps and services on the client to handle data (ports) Meeting reliability requirements of the apps Multiplexing to enable different communication conversations to be interleaved on the same network (pg. 5)

Which 3 fields are used in a UDP segment header? Window size Length Source port Acknowledgment number Checksum Sequence number

Length Source port Checksum (pg. 24)

Does UDP reorder the datagrams?

No, UDP reassembles the data in the order that it was received. (pg. 59)

Which 3 application layer protocols use TCP? SMTP FTP SNMP HTTP TFTP DHCP

SMTP FTP HTTP (pg. 19)

What information is used by TCP to reorder and reassemble segments?

Sequence number (pg. 17)

A client application needs to terminate a TCP communications session with a server. What is the 2nd step in the termination process? Client sends ACK Client sends FIN Client sends SYN Server sends ACK Server sends FIN Server sends SYN

Server sends ACK. (pg. 38)

Which two fields are included in the TCP header but not in the UDP header? Window Checksum Source port Destination port Sequence number

Window Sequence number (pg. 25)

What kind of applications use UDP

Applications that handle reliability themselves. (pg. 26)

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? 6001 4500 3001 6000

3001 (pg. 52)

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 6001 6000 4500

4501 (pg. 54)

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? 3001 1501 1500 6001

6001 (pg. 53)

Which 2 types of applications are best suited for UDP 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

Applications that handle reliability themselves Applications that can tolerate some data loss, but require little or no delay (pg. 13)

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 websites. The transport layer ensures the correct webpage is delivered to the correct browser window. A corporate worker is accessing a webserver located on a corporate network. The transport layer formats the screen so the webpage appears properly no matter what device is being used to view the website.

A student has two web browser windows open in order to access two websites. The transport layer ensures the correct webpage is delivered to the correct browser window. (pg. 33)

How are port numbers used in TCP/IP?

Allows conversations to be separated (pg. 29)

Which two characteristics are associated with UDP sessions? Destination devices receive traffic with minimal delay Transmitted data segments are tracked Destination devices reassembled messages and pass them to an application Received data is unacknowledged Unacknowledged data packets are retransmitted

Destination devices receive traffic with minimal delay Received data is unacknowledged (pg. 58)

What is the application for port number 443?

Hypertext Transfer Protocol Secure (HTTPS) (pg. 31)

What are 2 roles of the transport layer in data communication on a network? Identifying the proper application for each communication stream Tracking the individual communication between applications on the source and destination hosts Providing frame delimiting to identify bits making up a frame Performing a cyclic redundancy check on the frame for errors Providing the interface between applications and the underlying network over which messages are transmitted

Identifying the proper application for each communication stream Tracking the individual communication between applications on the source and destination hosts (pg. 6)

A client application needs to terminate a TCP communications session with a server. What is the 3rd step in the termination process? Client sends ACK Client sends FIN Client sends SYN Server sends ACK Server sends FIN Server sends SYN

Server sends FIN. (pg. 38)

What is the application for port number 25?

Simple Mail Transfer Protocol (SMTP) (pg. 31)

What is the application for port number 23?

Telnet (pg. 31)

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. (pg. 50)

What happens if a UDP client needs to send datagrams?

The client sends the datagram. (pg. 57)

What is the purpose of port numbers?

The port number tells the server which applications is wanting to be used on the server (pg. 28)

Which three statements characterize UDP? 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

UDP provides basic connectionless transport layer functions UDP relies on application layer protocols for error detection UDP is a low overhead protocol that does not provide sequencing or flow control mechanisms (pg. 62)

What are the six bits which control bit flags that indicate the status of the 3-way handshake?

URG - Urgent pointer field significant ACK - Acknowledgement flag used in connection establishment and session termination PSH - Push Function RST - Reset the connection when an error or timeout occurs SYN - Synchronize sequence numbers used in connection establishment FIN - No more data from sender and used in session termination (pg. 40)

In what 2 situations would UDP be better than TCP as the preferred transport protocol? 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

When a faster delivery mechanism is needed When applications do not need to guarantee delivery of the data (pg. 11)