CCC NET 125 Chapter 7

169.254.1.5

Match each description with an appropriate IP address: a link-local address

127.0.0.1

Match each description with an appropriate IP address: a loopback address

198.133.219.2

Match each description with an appropriate IP address: a public address

240.2.6.255

Match each description with an appropriate IP address: an experimental address

FF02::1

Match the IPv6 address with the IPv6 address type: all node multicast

2001:DB8::BAF:3F57:FE94

Match the IPv6 address with the IPv6 address type: global unicast

::1

Match the IPv6 address with the IPv6 address type: loopback

FF02::1:FFAE:F85F

Match the IPv6 address with the IPv6 address type: solicited node multicast

This network portion of the address is assigned by the provider.

Match the description to the IPv6 addressing component: global routing prefix

This part of the address is the equivalent to the host portion of an IPv4 address.

Match the description to the IPv6 addressing component: interface ID

This part of the address is used by an organization to identify subnets.

Match the description to the IPv6 addressing component: subnet ID

80

Match the port number with its associated protocol. HTTP

443

Match the port number with its associated protocol. HTTPS

143

Match the port number with its associated protocol. IMAP

25

Match the port number with its associated protocol: SMTP

23

Match the port number with its associated protocol: Telnet

The source decreases the amount of data that it transmits before it receives an acknowledgement from 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?

selective acknowledgement - SACK

Optional TCP feature that makes it possible for the destination to acknowledge bytes in discontinuous segments. With this, the source host would only need to retransmit the specific unacknowledged data rather than retransmitting all data since the last acknowledged data.

53

Port number associated with DNS

21

Port number associated with FTP

80

Port number associated with HTTP

143

Port number associated with IMAP

520

Port number associated with RIP

25

Port number associated with SMTP

161

Port number associated with SNMP

69

Port number associated with TFTP

23

Port number associated with Telnet

Well-known ports, reserved for services and applications.

Port number range 0 to 1023

Registered ports, assigned to user processes or applications

Port number range 1024 to 49151

Dynamic or private ports, also known as ephemeral ports, usually assigned dynamically to client applications when the client initiates a connection to a service.

Port number range 49152 to 65535

Transmission Control Protocol - TCP

A Layer 4 protocol of the TCP/IP model, TCP lets applications guarantee delivery of data across a network.

Header

A ________, used for data reassembly, is added to each block of data. This ______is used to track the data stream.

reliable

A characteristic of a protocol that uses mechanisms such as handshaking, timers, acknowledgement messages, and dynamic windowing to help ensure that data received is the same as the data sent. These kind of protocols require additional overhead on the network in terms of much larger segment headers.

client sends FIN server sends ACK server sends FIN client sends ACK

A client application needs to terminate a TCP communication session with a server. Place the termination process steps in the order that they will occur.

FTP makes use of TCP, so as soon as segments are lost in transit, the receiving device will send a decreased window size in returning segments.

A client is downloading a large file from a server using FTP. One of the segments is lost during transit. What will happen?

User Datagram Protocol - UDP

A connectionless transport layer protocol in the TCP/IP protocol stack. This is a simple protocol that exchanges datagrams without acknowledgements or guaranteed delivery, requiring that error processing and retransmission be handled.

ephermeral or private

A dynamic port in the range of 49152 to 65535 is also known as an _____ port

socket

A logical communications end point within a network device. It is typically represented by a Layer 3 address and a Layer 4 port number.

multiplexing

A process where multiple digital data streams are combined into one signal.

session

A related set of communications transactions between two or more network devices.

to test that the host has the capability to reach hosts on other networks

A user who is unable to connect to the file server contacts the help desk. The helpdesk technician asks the user to ping the IP address of the default gateway that is configured on the workstation. What is the purpose for this ping command?

expectational acknowledgement

Acknowledgement used by TCP where the ACK number is sent back to the source to indicate the next byte that the receiver expects to receive.

all IPv6 enabled devices on the local link​ or network

An IPv6 enabled device sends a data packet with the destination address of FF02::1. What is the target of this packet?​

TCP is appropriate when segments must arrive in a very specific sequence to be processed successfully and/or when all data must be fully received before any of it is considered useful. Examples are databases, web browsers, and email clients.

Application developers must choose which transport protocol type is appropriate based on the requirements of the applications. What are two examples of where a TCP is more appropriate.

Domain Name System - DNS Simple Network Management Protocol - SNMP Dynamic Host Configuration Protocol - DHCP Routing Information Protocol - RIP Trivial File Transfer Protocol - TFTP IP telephony or Voice over IP - VoIP Online games

Application layer protocols that use UDP include:

window size

As filed in the TCP header that is set in a sent segment, signifies the maximum amount of unacknowledged data the host is willing to receive before the other sending host must wait for an acknowledgement. Used for flow control.

conversation

At the transport layer, each particular set of data flowing between a source application and a destination application is known as a ____________________________.

port numbers

Both TCP and UDP use _____ to separate multiple communications on the same channel.

Transport

Chapter 7 focused on the ______________ layer. That layer is above the Network layer and below the session layer in the OSI Model.

header

Control information added before data during the encapsulation for network transmission.

best-effort delivery

Describes a network system that does not use a sophisticated acknowledgement system to guarantee reliable delivery of information.

TCP is considered a reliable, full-featured transport layer protocol, which ensures that all the data arrives at the destination. In contrast, UDP is a very simple transport layer protocol that does not provide any reliabilty.

Explain how TCP and UDP differ from each other

After a period of transmission with no data losses or constrained resources, the receiver begins to increase the window field, which reduces the overhead on the network, because fewer acknowledgements must be sent. The window size continues to increase until there is data loss, which causes the window size to decrease.

Explain how dynamic window sizes work.

Flow control is accomplished by limiting the amount of data segments forwarded at one time and by requiring acknowledgements of receipt prior to sending more.

Explain how flow control is accomplished.

Flow control helps maintain the reliability of TCP transmission by adjusting the rate of data flow between source and destination for a given session.

Explain the purpose of flow control.

The transport layer provides a method of delivering data across the network in a way that ensures that the data can be properly put back together on the receiving end, and provides the segmentation of data and the controls necessary to reassemble these segments into the various communication streams.

Explain the purpose of the transport layer.

The initiating client requests a client-to-server communication session with the server. The server acknowledges the client-to-server communication session and requests a server-to-client communication session. The initiating client acknowledges the server-to-client communication session.

Explain the three steps in TCP connection establishment.

The three-way handshake: Establishes that the destination device is present on the network Verifies that the destination has an active service and is accepting requests on the destination port number that the initiating client intends to use for the session. Informs the destination device that the source client intends to establish a communication session on that port number.

Explain what occurs during a three-way handshake.

Denying the establishment of TCP sessions. Only allowing sessions to be established for specific services. Only allowing traffic as a part of already established sessions.

How can security be added to the data network?

By numbering and sequencing the segments, TCP can ensure that segments are reassembled into the proper order.

How does TCP ensure that its segments are reassembled into the proper order?

The three-way handshake starts when a client device sends an ISN to the server. The server responds with an acknowledgement of the ISN+1 and its own ISN. The last step in the process is when the client acknowledges the server ISN by responding with a value of the server ISN+1.

If a client sends an ISN of 2 to a server and a server responds with an ISN of 1 to the client, what is the final stage of the TCP three-way handshake?

User Datagram Protocol ( UDP)

In TCP/IP, the segmentation and reassembly processes can be achieved using two different transport layer protocols: Transmission Control Protocol ( TCP) and _________.

Multiplexing

_____ is the term used to describe the interweaving of data from multiple users on the same network.

port

In networking, this term is used in several ways. With Ethernet hub and switch hardware, this is simply another name for interface, which is a physical connector in the switch into which a cable can be connected. With TCP and UDP, this is a software function that uniquely identifies a software process on a computer that uses TCP or UDP. With PCs, this can be a physical connector on the PC, as in parallel or USB.

SLAAC

In which alternative to DHCPv6 does a router dynamically provide IPv6 configuration information to hosts?

sequence number

Information placed in a data header to ensure correct sequencing of the arriving data.

UDP

Label each of the following delivery method characteristics as either TCP or UDP: Fast transmission requirements

TCP

Label each of the following delivery method characteristics as either TCP or UDP: Guaranteed delivery

UDP

Label each of the following delivery method characteristics as either TCP or UDP: Less overhead

UDP

Label each of the following delivery method characteristics as either TCP or UDP: connectionless

TCP

Label each of the following delivery method characteristics as either TCP or UDP: flow control

UDP

Label each of the following delivery method characteristics as either TCP or UDP: no acknowledgement of receipt

UDP

Label each of the following delivery method characteristics as either TCP or UDP: no ordered delivery

TCP

Label each of the following delivery method characteristics as either TCP or UDP: ordered delivery

TCP

Label each of the following delivery method characteristics as either TCP or UDP: sequenced message segments

TCP

Label each of the following delivery method characteristics as either TCP or UDP: session establishment

UDP

Label the following application protocols with its correct transport layer delivery method. Either TCP, UDP, or Both: DHCP

Both

Label the following application protocols with its correct transport layer delivery method. Either TCP, UDP, or Both: DNS

TCP

Label the following application protocols with its correct transport layer delivery method. Either TCP, UDP, or Both: FTP

TCP

Label the following application protocols with its correct transport layer delivery method. Either TCP, UDP, or Both: HTTP

UDP

Label the following application protocols with its correct transport layer delivery method. Either TCP, UDP, or Both: IPTV

TCP

Label the following application protocols with its correct transport layer delivery method. Either TCP, UDP, or Both: SMTP

Both

Label the following application protocols with its correct transport layer delivery method. Either TCP, UDP, or Both: SNMP

UDP

Label the following application protocols with its correct transport layer delivery method. Either TCP, UDP, or Both: TFTP

TCP

Label the following application protocols with its correct transport layer delivery method. Either TCP, UDP, or Both: Telnet

UDP

Label the following application protocols with its correct transport layer delivery method. Either TCP, UDP, or Both: VoIP

UDP is appropriate when an application can tolerate some data loss during transmission over the network, but delays in transmission are unacceptable. Examples are streaming audio, video, and VoIP.

List the applications where UDP is the preferred transfer protocol.

Connectionless. Unreliable delivery. No ordered data recontruction. No flow control.

List the features used to describe UDP.

datagram

Logical grouping of information sent as a network layer unit over a transmission medium without prior establishment of a virtual circuit. IP these are the primary information units in the Internet. The terms frame, message, packet, and segments are also called these.

initial sequence number - ISN

Randomly chosen number and is used to begin tracking the flow of data from the client to the server for this session. This in the header of each segment is increased by one for each byte of data sent from the client to the server as the data conversation continues.

All of these items listed are properties of TCP.

Select the best answer. Which of these is not a property of TCP? Select one: a. Ordered data reconstruction b. All of these items listed are properties of TCP. c. Connection oriented conversations d. Flow Control e. Reliable Delivery

Reliable Delivery

Select the item that is not considered a feature or property of UDP. Select one: a. No Flow Control b. Connectionless c. Reliable Delivery d. No ordered data reconstruction

True

TCP breaks up a message into small pieces known as segments. The segments are numbered in sequence and passed to the IP process for assembly into packets. TCP keeps track of the number of segments that have been sent to a specific host from a specific application.

Source and destination - ports Sequencing for same order delivery Acknowledgement of received segments Flow control and congestion management

TCP header provides for:

A connection-oriented protocol is one that negotiates and establishes a permanent connection, or session, between source and destination devices prior to forwarding any traffic.

TCP is a connection-oriented protocol. Explain what a connection-oriented protocol is.

False

TCP provides just the basic functions for delivering data segments between the appropriate applications, with very little overhead and data checking. TCP is known as a best- effort delivery protocol.

window sizes

TCP uses ________ to attempt to manage the rate of transmission to the maximum flow that the network and destination device can support, while minimizing loss and retransmissions.

Connection-oriented conversations by establishing sessions. Reliable delivery. Ordered data reconstruction. Flow control.

TCP was initially described in RFC 793. In addition to supporting the basic functions of data segmentation and reassembly, TCP also provides:

Additional overhead and possible delays in transmission.

TCP's reliability functions provide more robust communication between applications. What are two possible issues that can be incurred by this reliability?

Transmission Control Protocol - TCP and User Datagram Protocol - UDP

TCP/IP provides two transport layer protocols. These are:

connection-oriented

Term used to describe data transfer that requires the establishment of a virtual circuit.

00000111

The 8-digit binary value of the last octet of the IPv4 address 172.17.10.7 is:

false

The combination of the source and destination IP addresses and the source and destination port numbers is known as a datagram.

The socket is used to identify the server and service being requested by the client.

The combination of the source and destination IP addresses and the source and destination port numbers is known as a socket. What is a socket used for?

connection-oriented

The key distinction between TCP and UDP is reliability. The reliability of TCP communication is obtained through the use of _______________________________ sessions.

10.15.25.254/24

The last host address on the 10.15.25.0/24 network is:

172.16

The network portion of the address 172.16.30.5/16 is

UDP

______ is a very simple transport layer protocol that does not provide any reliability.

Negotiates the signalling mechanism used by the medium

The primary responsibilities of the Transport layer are all these except for this. Select the answer that does not belong. Select one: a. Tracking the individual communication between applications on the source and destination hosts b. Segmenting data for manageability and reassembling segmented data into streams of application data at the destination c. Negotiates the signalling mechanism used by the medium. d. Identifying the proper application for each communication stream

three-way handshake

The process used by TCP to establish a session.

2001:DB8:0:1470::200

The shortest compressed format of the IPv6 address is:

Applications that can tolerate some data loss, but require little or no delay. Applications with simple request and reply transactions. Unidirectional communications, where reliability is not required or can be handled by the application.

There are three types of applications that are best suited for UDP. Explain each.

port

There can be many applications or services running on each host in the network. The transport layer assigns each application an identifier. This identifier is called a _________.

Dynamic or private ports - Numbers 49152 to 65535

These are usually assigned dynamically to client applications when the client initiates a connection to a service.

Well-known ports - Numbers 0 to 1023

These numbers are reserved for services and applications. They are commonly used for applications such as HTTP ( web server), Internet Message Access Protocol ( IMAP)/ Simple Mail Transfer Protocol ( SMTP) ( email server), and Telnet.

Registered ports - Numbers 1024 to 49151

These port numbers are assigned to user processes or applications. These processes are primarily individual applications that a user has chosen to install, rather than common applications that would receive a lower port number.

A FIN segment and an ACK segment.

To end each one-way TCP session, a two-way handshake is used which consists of...

stateful

Tracking of actual conversations and their state of the communication session for a protocol, such as TCP.

Source and destination - ports

UDP header provides for:

UDP is a stateless protocol, meaning that neither the client nor the server is obligated to keep track of the state of the communication session.

UDP is a stateless protocol. Explain what this means.

When an application has data to send, it simply sends the data.

UDP is said to be transaction-based. What does this mean?

netstat

What DOS command can be used to see which active TCP connections are open and running on a networked host?

The destination host can acknowledge bytes in discontinuous segments and the source host would only need to retransmit the missing data.

What advantage does selective acknowledgements (SACKs) offer?

The pieces of communication in UDP are called datagrams.

What are the pieces of communication in UDP called?

The transport layer is responsible for segmenting data, adding the port number to identify the proper application, and keeping track of individual conversations. MAC addresses are added by the data link layer, and IP addresses and routing are handled by the network layer.

What are the primary purposes of the transport layer?

Tracking the individual communication between applications on the source and destination hosts. Segmenting data for manageability and reassembling segmented data into streams of application data at the destination. Identifying the proper application for each communication stream.

What are the primary responsibilities of transport layer protocols?

The sequence number - SEQ - and the acknowledgement number - ACK - are used together to confirm receipt of the bytes of data contained in the transmitted segments.

What are the sequence (SEQ) number and acknowledgement (ACK) numbers used together for?

TCP

______ is considered a reliable, full- featured transport layer protocol, which ensures that all the data arrives at the destination.

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.

What are three responsibilities of the transport layer?

UDP reassembles the data in the order received and passes it to the application. It is up to the application to sort out the data. UDP has no mechanism for reordering of datagrams or requesting retransmission.

What does UDP do when receiving messages that are more than one datagram in length?

the amount of data that can be sent before an acknowledgment is required

What does the value of the window size specify?

Sequence numbers

What information is assigned to each header to ensure that it is reassembled in the correct order?

TCP uses acknowledgements and windowing to offer flow control and reliable delivery. UDP is connectionless and does not resend lost datagrams.

What is a characteristic of UDP?

A stateful protocol is a protocol that keeps track of the state of the communication session. TCP is considered a stateful protocol.

What is a stateful protocol?

UDP communication requires less overhead.

What is an advantage of UDP over TCP?

UDP does not track conversations and has the advantage of low overhead relative to TCP.

What is an advantage that UDP has over TCP?

Source port addresses are assigned by the transport layer to identify the individual conversation and destination port addresses to identify the service being looked for.

What is assigned by the transport layer to identify an application or service?

/27

What is the prefix length notation for the subnet mask 255.255.255.224?

to request that a source decrease the rate at which it transmits data

What is the purpose of the TCP sliding window?

The source port number is randomly generated by the sending device to identify a conversation between two devices. The separate conversations are tracked based on the source ports.

What is the purpose of the source port number?

to keep track of multiple conversations between devices

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

The FIN control bit indicates that there is no more data from the sender.

Which TCP header control bit is set on to terminate a TCP conversion?

The acknowledgement number indicates that the data has been received, the header length indicates the length of the TCP segment header, the window size specifies the number of segments that can be received before an acknowledgement is required, and the checksum is used for error-checking the segment header and data.

Which TCP header field specifies the number of segments that can be accepted before an acknowledgement is required?

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?

Hypertext Transfer Protocol - HTTP File Transfer Protocol - FTP Simple Mail Transfer Protocol - SMTP Telnet

Which applications use TCP?

tunneling

Which network migration technique encapsulates IPv6 packets inside IPv4 packets to carry them over IPv4 network infrastructures?

192.168.1.1:80

Which number or set of numbers represents a socket?

TCP 3-way handshake

Which transport layer feature is used to guarantee session establishment?

web servers, printers

Which two types of devices are typically assigned static IP addresses?

link-local address

Which type of IPv6 address is not routable and used only for communication on a single subnet?

Applications that are simple request and reply transactions, those sensitive to delay, and those that are unidirectional in nature make use of UDP. Applications requiring reliable delivery and that can tolerate delay associated with protocol overhead make use of TCP

Which types of applications would use UDP?

The client places a destination port number in the segment to tell the destination server what service is being requested.

Why does a client place a destination port number in a segment?

Dividing application data into segments both ensures that data is transmitted within the limits of the media and that data from different applications can be multiplexed on to the media.

Why is dividing application data into segments necessary?

transport

With UDP, there are no ___________________ layer processes that inform the sender if successful delivery has occurred.