Chapter 14 - Transport Layer Flashcards
Which layer is responsible for establishing a temporary communication session between the source and destination host applications?
Transport Layer
Which three are transport layer responsibilities?
Conversation Multiplexing
Segmenting data and reassembling segments
Tracking individual conversations
Which transport layer protocol would be used for VoIP applications?
UDP
Which TCP header statement is true?
It contains of 10 fields in a 20 byte header
Port
Number Protocol Application
0 TCP File Transfer Protocol (FTP) - Data
21 TCP File Transfer Protocol (FTP) - Control
22 TCP Secure Shell (SSH)
23 TCP Telnet
25 TCP Simple Mail Transfer Protocol (SMTP)
53 UDP, TCP Domain Name System (DNS)
67 UDP DHCP - Server
68 UDP DHCP - Client
69 UDP Trivial File Transfer Protocol (TFTP)
80 TCP Hypertext Transfer Protocol (HTTP)
110 TCP Post Office Protocol version 3 (POP3)
143 TCP Internet Message Access Protocol (IMAP)
161 UDP Simple Network Management Protocol (SNMP)
443 TCP HTTPS
Which of the following would be valid source and destination ports for a host connecting to an email server?
Source 49152 Destination 25
Which control bit flags are used during the three-way handshake?
SYN and ACK
How many exchanges are needed to end both sessions between two hosts during two way handshake?
Four exchanges
Which TCP field is used by the destination host to reassemble segments into the original order?
Sequence Number
Which TCP field is used to provide flow control?
Window Size
What happens when a sending host senses there is congestion?
The sending host reduces the number of bytes it sends before receiving an acknowledgment from the destination host.
Why is UDP desirable for protocols that make a simple request and reply transactions?
Low overhead
Which UDP datagram reassembly statement is true?
UDP reassembles the data in the order that it was received.
Which of the following would be valid source and destination ports for a host connecting to a DNS server?
Source 49152 Destination 53
Which transport layer feature is used to establish a connection-oriented session?
TCP 3- way handshake
What is the complete range of TCP and UDP well-known ports?
0-1023
What is a socket?
The combination of a source IP address and port number or a destination IP address and port number.
How does a networked server manage requests from multiple clients for different services?
Each request has a combination of source and destination port numbers, coming from a unique IP address.
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
What type of applications are best suited for using UDP?
Applications that are sensitive to delay
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 acknowledgment from the destination.
Which two operations are provided by TCP but not by UDP?
Acknowledging received data
Retransmitting any unacknowledged data
What is the purpose of using a source port number in a TCP communication?
To keep track of multiple conversations between devices
Which two flags in the TCP header are used in a TCP three-way handshake to establish connectivity between two network devices?
ACK
SYN
Which 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 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 two services or protocols use the preferred UDP protocol for fast transmission and low overhead?
VoIP and DNS
Which number or set of numbers represents a socket?
Example = 192.168.1.1.80
What is a responsibility of transport layer protocols?
Tracking individual conversations
