Module 14 (Transport Layer)

Length

A 16-bit field that indicates the length of the UDP datagram header.

HTTP, FTP, SMTP, SSH

Applications that use TCP

DHCP, DNS, SNMP, TFTP, VoIP, Video Conferencing

Applications that use UDP

10.1.1.10:1099, 10.1.1.254:80

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?

The source decreases the amount of data that it transmits before it receives an acknowledgement form the destination

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?

Socket

The combination of the source IP address and source port number, or the destination IP address and destination port number is known as

Registered Ports

These port numbers 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 1812 for its RADIUS server authentication process. 1,024 to 49,151

Well-known Ports

These port numbers are reserved for common or popular services and applications such as web browsers, email clients, and remote access clients. Defined well-known ports for common server applications enables clients to easily identify the associated service required. 0 to 1,023

Private and/or Dynamic Ports

These ports are also known as ephemeral ports. The client's OS usually assign port numbers dynamically when a connection to a service is initiated. The dynamic port is then used to identify the client application during communication. 49,152 to 65,535

True

To pass data streams to the proper applications, the transport layer identifies the target application using an identifier called a port number

sliding window

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?

Sequence Number

What field is used by the destination host to reassemble segments into the original order?

Window Size

What field is used to provide flow control?

The part of the FTP message that was lost is re-sent

What happens if part of an FTP message is not delivered to the destination?

The sending host reduces the number of bytes it sends before receiving an acknowledgement from the destination host.

What happens when a sending host senses there is congestion?

TFTP, VoIP

Which two applications would use the UDP transport layer protocol? (Choose two.) FTP HTTP ICMP TFTP VoIP

Source port number and Destination port number

Which two fields are the same in a TCP and UDP header? (Choose two.) Control bits Destination port number Sequence number Source port number Well-known port number

ACK, SYN

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

retransmitting any unacknowledged data, acknowledging received data

Which two operations are provided by TCP but not by UDP? (Choose two.)

DNS, VoIP

Which two services or protocols use the preferred UDP protocol for fast transmission and low overhead? (Choose two)

Low overhead

Why is UDP desirable for protocols that make a simple request and reply transactions?

TCP

provides reliable, ordered, and error-checked delivery of a stream of packets on the internet. TCP is tightly linked with IP and usually seen as TCP/IP in writing.

Transport Layer Protocols

specify how to transfer messages between hosts, and are responsible for managing reliability requirements of a conversation. The ___ layer includes the TCP and UDP protocols.

protocols in use, the local address and port numbers, the foreign address and port numbers, and the connection state.

the command netstat will list the:

Checksum

A 16-bit field used for error checking of the datagram header and data.

Checksum

A 16-bit field used for error checking of the segment header and data.

Destination Port

A 16-bit field used to identify the destination application by port number.

Source Port

A 16-bit field used to identify the source application by port number.

Urgent

A 16-bit field used to indicate if the contained data is urgent.

Window size

A 16-bit field used to indicate the number of bytes that can be accepted at one time.

Sequence Number

A 32-bit field used for data reassembly purposes.

Acknowledgment Number

A 32-bit field used to indicate that data has been received and the next byte expected from the source.

Control bits

A 6-bit field that includes bit codes, or flags, which indicate the purpose and function of the TCP segment.

Reserved

A 6-bit field that is reserved for future use.

UDP

A protocol used on the internet for fast transmission of information but with minimal error checking

Each request has a combination of source and destination port numbers, coming from a unique IP address

How does a networked server manage requests from multiple clients for different services?

four exchanges

How many exchanges are needed to end both sessions between two hosts?

0 through 65535

The Internet Assigned Numbers Authority (IANA) is the standards organization responsible for assigning various addressing standards, including the 16-bit port numbers. The 16 bits used to identify the source and destination port numbers provides a range of ports from

tracking individual conversations

What is a responsibility of transport layer protocols?

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

What is a socket?

0 to 1023

What is the complete range of TCP and UDP well-known ports?

to keep track of multiple conversations between devices

What is the purpose of using a source port number in a TCP communication?

applications that are sensitive to delay

What type of applications are best suited for using UDP?

It consists of 10 fields in a 20-byte header.

Which TCP header statement is true? It consist of 4 fields in an 8-byte header. It consist of 8 fields in a 10-byte header. It consists of 10 fields in a 20-byte header. It consists of 20 fields in a 40-byte header.

UDP reassembles the data in the order hat it was received

Which UDP datagram reassembly statement is true?

The client randomly selects a source port number

Which action is performed by a client when establishing communication with a server via the use of UDP at the transport layer?

True

the transport layer is the link between the application layer and the lower layers that are responsible for network transmission.

It consist of 4 fields in an 8-byte header

Which UDP header statement is true? It consist of 4 fields in an 8-byte header. It consist of 8 fields in a 10-byte header. It consists of 10 fields in a 20-byte header. It consists of 20 fields in a 40-byte header.

netstat

Which Windows command would display the protocols in use, the local address and port numbers, the foreign address and port numbers, and the connection state? ipconfig /all ping netstat traceroute

SYN and ACK

Which control bit flags are used during the three-way handshake?

Transport layer

Which layer is responsible for establishing a temporary communication session between the source and destination host applications?

192.168.1.1:80

Which number or set of numbers represents a socket?

UDP

Which of the following is a stateless best-effort delivery transport layer protocol? ICMP IP TCP UDP

Source: 49152, Destination: 53

Which of the following would be valid source and destination ports for a host connecting to a DNS server?

Source: 49152, Destination: 25

Which of the following would be valid source and destination ports for a host connecting to an email server?

well-known ports

Which port group includes port numbers for FTP, HTTP, and TFTP applications?

Conversation multiplexing, segmenting data and reassembling segments, tracking individual conversations

Which three are transport layer responsibilities? (Choose three.)

TCP

Which transport layer protocol ensures reliable same-order delivery? ICMP IP TCP UDP

UDP is a best-effort delivery protocol

Which transport layer protocol statement is true? TCP has fewer fields than UDP. TCP is faster than UDP UDP is a best-effort delivery protocol UDP provides reliability

User Datagram Protocol (UDP)

Which transport layer protocol would be used for VoIP applications? Session Information Protocol (SIP) Transmission Control Protocol (TCP) User Datagram Protocol (UDP) VoIP Transfer Protocol

FTP, HTTP

Which two applications would use the TCP transport layer protocol? (Choose two.) FTP HTTP ICMP TFTP VoIP

Header Length

A 4-bit field known as ʺdata offsetʺ that indicates the length of the TCP segment header.

TCP 3-way handshake

Which transport layer feature is used to establish a connection-oriented session?