1. What ordering of TCP flags make up the Three-Way Handshake?
Answers
·
SYN, SYN/ACK, ACK
·
SYN, ACK, FIN
·
FIN, FIN/ACK, ACK
· SYN, ACK, SYN, ACK
2. Transport layer
protocols, like TCP and UDP, introduce the concept of a port. How many bits are
in a port field?
Answers
·
32
·
8
·
4
·
16
Explanation: Because the port field in TCP and UDP headers consists of 16 bits, it is capable of representing port numbers in the range of 0 to 65535. This enables a diverse selection of alternative port assignments that may be used for a variety of communication functions. Higher port numbers are often allocated for dynamically issued or private uses, whereas port numbers lower than 1024 are typically designated for well-known service protocols.
3. A device that blocks
traffic that meets certain criteria is known as a ________.
Answers
·
Firewall
·
Hub
·
Router
·
Switch
Explanation: A firewall is a piece of hardware that restricts traffic
depending on predetermined rules and conditions. Firewalls are a kind of
network security device that monitor and restrict network traffic coming into
and going out of a network depending on certain security criteria that have
been defined. They may take the form of hardware devices, software programs, or
a mix of the two, and their primary function is to create a barrier between a
trusted internal network and an untrusted external network such as the
internet. This barrier may take the form of either a hardware device or a
software application. Firewalls have the ability to filter and prohibit traffic
based on a wide variety of criteria, such as IP addresses, port numbers, and
particular content or protocols.
4. Which TCP flag is
used to make the listening program respond immediately?
Answers
·
URG
·
ACK
·
PSH
·
RST
Explanation: The URG (Urgent) flag is a kind of TCP flag that may be
used to force an urgent response from the listening application. When the URG
flag in a TCP segment is set, it signifies that the significance of the urgent
pointer field can no longer be ignored. The urgent pointer directs attention to
the conclusion of the urgent data included inside the segment.
This flag is intended to signal to the receiving software
that the data should be processed as quickly as possible. Typically, the usual
processing would be interrupted so that the urgent data may take precedence.
It's a means for the sender to let the receiver know that specific data in the
segment has to be handled with quick attention or priority, and it's a way that
the sender may communicate this to the receiver.
5. _________are
identified as ports 49152 through 65535.
Answers
·
Sockets
·
System ports
·
User ports
·
Ephemeral ports
Explanation: Ports with numbers ranging from 49152 all the way up to 65535 are often referred to as "private" or "dynamic" ports. When an application or process needs to create a connection to a network, it will often choose a port from this range since these ports are used for communication that is either dynamic or private. It is standard practice to utilize them for ephemeral or transitory purposes, such as client-side communication with servers on well-known ports. They are not allocated to any particular application by the Internet allocated Numbers Authority (IANA), and they are not used for any other reason.
6. Unlike our five-layer
model, the OSI network model adds two more layers on top of the Application
Layer. Select examples of these new layers below.
Answers
·
The presentation layer
·
The interconnection layer
·
The session layer
· The compression layer
7. An example of
something that operates at the application layer is:
Answers
·
UDP
·
TCP
·
A web browser
·
A router
Explanation: Web browsers are the prototypical example of applications
that function at the application layer of the OSI model. When you use a web
browser such as Chrome, Firefox, or Safari, you are interacting with an
application that operates at the application layer, which is the topmost tier
in the networking stack.
Web browsers provide users the ability to access the
numerous services and resources available on the internet, such as websites,
web pages, and online apps, and to interact with those resources. In order to
interface with web servers and access online information, they make use of
application layer protocols such as HTTP (Hypertext Transfer Protocol) and
HTTPS (Hypertext Transfer Protocol Secure).
Therefore, whenever you engage with an application that operates at the application layer of the OSI model, such as when you are browsing the web, checking your email, or using other services that are based on the internet, you are doing so through a web browser.
8. What's the standard
number for a TTL field?
Answers
·
8
·
16
·
32
·
64
Explanation: The Time-to-Live (TTL) field of an IP (Internet Protocol)
packet is an 8-bit field that reflects the maximum number of hops (routers)
that a packet is permitted to travel before it is discarded. This field
determines whether or not a packet is allowed to continue its journey across
the network. 64 is the default value to use as the first setting for the TTL
field.
This implies that the TTL field of a packet is set to 64
when it is transmitted, and the value of the TTL field is decreased by 1 each
time the packet travels through a router. When the time to live (TTL) field
hits zero, the packet is thrown away, and an ICMP (Internet Control Message
Protocol) message may be sent back to the source to indicate that the packet
has run out of time.
It is standard practice to use 64 as the default beginning value; however, this amount may be changed to a variety of other values based on the operating system or the network settings.
9. Which part of the
operating system does the application use to communicate the need to establish
a TCP connection?
Answers
·
ARP message
·
Networking stack
·
The source port
·
The router
Explanation: Whenever an application wants to create a TCP (Transmission
Control Protocol) connection, it will normally make use of a series of system
functions that are made available by the networking stack of the operating
system. These system calls are the means by which the application initiates
communication with the operating system in order to begin the process of
establishing a TCP connection.
Socket APIs, which stand for Application Programming
Interfaces, are used in the vast majority of programming environments to enable
applications to communicate with operating systems. The particular system calls
for establishing a TCP connection include methods such as socket(), which can
be used to construct a socket; bind(), which can be used to associate the
socket with a local address; connect(), which can be used to make a connection
to a distant address; and listen(), which can be used by a server to begin
listening for incoming connections.
These system calls serve as a bridge between the networking capabilities of the operating system and the application, enabling the program to express its networking requirements and create TCP connections for the purpose of data exchange.
10. Which section of the
TCP/IP Five-Layer Network Model contains the data the application wants to
send?
Answers
·
The payload section of the Ethernet
frame
·
The payload section of the IP Datagram
·
The payload of the TCP
segment
·
The header of the Ethernet frame
Explanation: The "Application Layer" is the component of the
TCP/IP Five-Layer Network Model that holds the data that the application wishes
to convey. The Application Layer is the very last layer in the paradigm, and it
is the one that is in charge of delivering network services directly to
applications or end users.
The Application Layer is where data that was created by an
application, such as a web browser or email client, may be found. At this tier,
the application is responsible for formatting the data and maintaining
communication with the layers below it in order to guarantee accurate
transmission across the network.
Encapsulation is a process that occurs when data travels
down the levels of the TCP/IP architecture. This process involves each layer
adding the header information that is specific to that layer to the payload. At
some point, the data will be divided into packets at one of the lowest levels,
and then they will be sent across the network.
11. The transport layer handles
multiplexing and demultiplexing through what type of device?
Answers
·
Switches
·
Hubs
·
Routers
·
Ports
Explanation: The transport layer is
responsible for multiplexing and demultiplexing, and it does so by using
"ports." Within a single networking device, differentiating between
several communication streams is accomplished via the use of ports.
Multiplexing
is the process of merging numerous data streams into a single stream, while
demultiplexing is the process of separating the separate streams from the
combined stream. Multiplexing and demultiplexing are also referred to as the
process of multiplexing.
Each
communication endpoint (such as an application or process) is identified in the
context of the transport layer by a combination of an IP address and a port
number. This may be done in a variety of ways. The combination of an IP address
and a port number makes it possible to identify individual communication
streams in a way that is completely unique.
For
instance, the Transmission Control Protocol (TCP) and the User Datagram
Protocol (UDP) in the TCP/IP protocol suite employ port numbers to
differentiate between the many services or applications that are operating on a
device. The transport layer utilizes the port number to demultiplex the
incoming packets and then delivers them to the relevant application or process
when data is received.
12. Which field in the TCP header
provides the information for the receiving network device to understand where
the actual data payload begins?
Answers
·
Checksum
·
Data offset
·
Acknowledgement
number
·
Sequence
number
Explanation: The "Data
Offset" or "Header Length" field is the part of the TCP
(Transmission Control Protocol) header that contains the information that tells
the network device that is receiving the data where the actual data payload
begins. This information is provided in the TCP header. This field provides a
32-bit word representation of the total length of the TCP header.
The
beginning location of the data inside the TCP segment is indicated by the value
included in the Data Offset field. This field assists the receiving device in
locating the beginning of the actual data payload by allowing it to account for
the fact that the length of the TCP header can change depending on the presence
of optional fields.
The Data
Offset field consists of four bits, and the value contained inside these bits
is multiplied by 32 bits in order to calculate the entire length of the TCP
header. This, in turn, contributes to the process of locating the data inside
the TCP segment by helping to determine its location.
13. A device involved in a
Transmission Control Protocol (TCP) connection is ready to close the
connection. The other device in the connection agrees. What has occurred?
Answers
·
Two-way
handshake
·
Three-way
handshake
·
Handshake
·
Four-way handshake
14. If a TCP socket is ready and
listening for incoming connections, it's in the ______ state.
Answers
·
CLOSE_WAIT
·
ESTABLISHED
·
SYN_SENT
·
LISTEN
Explanation: When a TCP socket is in
the "LISTEN" state, it means that it is prepared to accept new
connections and is actively listening for them. In the context of the TCP
protocol, the LISTEN state denotes the status of a server socket that is
actively listening for connection requests from clients. This kind of server
socket is said to be in the "listen" state. When a client wishes to
create a connection with the server, it sends a SYN (Synchronize) segment, and
the server switches from the LISTEN state to the state that corresponds to an
established connection when it receives this segment.
15. A communication sent through
Transmission Control Protocol (TCP) arrives out of order. What allows the data
to be put back together in the correct order?
Answers
·
Acknowledgement
number
·
Sequence numbers
·
Checksum
·
Preamble
Explanation: The use of sequence
numbers and acknowledgment numbers is the method that is utilized by
Transmission Control Protocol (TCP), and it is this process that enables
out-of-order segments to be reassembled in the appropriate order. Every TCP
segment has its own unique sequence number, which pinpoints exactly where in
the stream the data being sent is located.
Before
transferring the data to the higher-layer application, the receiving TCP stack
will utilize the sequence numbers to rearrange the segments if they come out of
order. It is the job of the acknowledgment numbers included inside the TCP
header to both advise the sender about the next anticipated sequence number and
to acknowledge the reception of individual segments.
The sender
resends any segments that are not recognized by the recipient, which enables
the receiver to reconstruct any segments that were lost or received out of
order. This procedure, in conjunction with the use of sequence and
acknowledgment numbers, helps to assure the dependable and well-organized
transmission of data inside a TCP connection.
16. In the OSI network model, the
________ is responsible for facilitating the communication between actual
applications and the transport layer.
Answers
·
session layer
·
application
layer
·
physical
layer
·
presentation
layer
Explanation: The "Application
Layer" of the OSI network model is the part of the model that is in charge
of allowing communication between the real applications and the transport
layer. The Application Layer is the layer that sits between the software programs
that need network services and the network itself. It offers network services
directly to end users or applications and acts as the interface between the
two.
The
Application Layer is responsible for a variety of functions, including the
provision of network access to application software, the facilitation of
communication and the exchange of data between multiple applications, and the
provision of a variety of network services, including file transfer, electronic
mail, and remote login.
The
Application Layer is essentially the layer that is responsible for user
interfaces as well as application-level protocols, which makes it possible for
software programs to connect with one another across a network.
17. You are sending a very small
amount of information that you need the listening program to respond to
immediately. Which Transmission Control Protocol (TCP) flag will be used?
Answers
·
ACK
·
RST
·
PSH
·
URG
Explanation: You might use the
"Urgent" (URG) flag in a Transmission Control Protocol (TCP)
transmission if you require the listening application to reply promptly to a
very little quantity of information in the event that the information is sent
over the protocol. The TCP header has a flag called URG that, when set,
indicates that the data in the TCP segment is very time-sensitive and demands
quick attention.
When the
URG flag is set, it is often accompanied by an urgent pointer field in the TCP
header that identifies the end of the urgent data. This field indicates where
the data will be dropped if it is not sent immediately. Because of this, the
sender is able to indicate to the recipient that certain data included inside
the segment is either time-sensitive or needs priority processing.
Keep in
mind that the usage of the URG flag is application-dependent, and that in order
for communication to take place effectively, both the transmitting application
and the receiving application need to support and comprehend it.
18. What layer of the TCP/IP
Five-Layer Network Model allows applications to communicate in a way they
understand?
Answers
·
Data
layer
·
User
layer
·
Application layer
·
Transport
layer
Explanation: The "Application
Layer" is the name given to the part of the TCP/IP Five-Layer Network
Model that facilitates communication between programs in a format that those
apps can comprehend. The Application Layer is the very last layer in the
paradigm, and it serves as a platform that enables different software programs
to connect with one another across a network.
This layer
is in charge of delivering network services straight to end users or
applications and is accountable for doing so. It incorporates a wide variety of
protocols and services that make it possible for applications to connect with
one another, comprehend the data formats used by one another, and share
information. The Hypertext Transfer Protocol (also known as HTTP), the File
Transfer Protocol (often known as FTP), the Simple Mail Transfer Protocol (also
known as SMTP), and many more protocols are examples of application layer
protocols.
In a
nutshell, the Application Layer serves as the interface between the actual
software programs and the network itself, making it possible for the two to
interact with one another in a manner that is clear to both parties.
19. What port does the File Transfer
Protocol (FTP) typically listen on?
Answers
·
21
·
80
·
443
·
25
When it is
operating in active mode, the FTP server will check for incoming data
connections on port 20. When using passive mode, the server chooses a port for
the client to connect to, and the client then transfers data using the port
that was chosen by the server. On the other hand, port 21 is always used for
the connection that controls the system and is where instructions and replies
are traded.
Answers
·
TCP
·
address
·
sequence
·
acknowledgement
Explanation: The term "sequence
number" refers to a 32-bit value that determines where you are in the
progression of TCP segments. This number is used to keep track of where you are
in the progression. The sequence number is an essential component of TCP connection
because it plays an important role in preserving the order of sent data and
ensuring its trustworthiness.
In the
header of every TCP segment is a sequence number field, and the value of this
field shows where the data fits in the larger context of the entire sequence of
data that is being broadcast. The TCP stack that is doing the receiving
utilizes the sequence numbers to appropriately organize and reassemble the
segments that it has received. This ensures that the data is sent correctly to
the application that is operating at a higher tier.
Shuffle Q/A 1
21. The concept of taking traffic that’s all aimed at the same
node and delivering it to the proper receiving service is known as _________.
Answers
·
encapsulation
·
multiplexing
·
routing
·
demultiplexing
When it
comes to networking, multiplexing is a technique that assists in the process of
directing various forms of communication (for example, those coming from
distinct applications or services) to the correct location on a node or
network. This procedure guarantees that data coming from a variety of sources
may be sent and received continuously without being disrupted by interference.
Answers
·
Checksum
·
Data
offset
·
Sequence
number
·
Acknowledgement number
Explanation: The "Acknowledgment
Number" field is the part of the header of a Transmission Control Protocol
(TCP) packet that contains the information about the next anticipated segment.
The sequence number of the next data byte that the receiver is anticipating
receiving from the sender is stored in the Acknowledgment Number field.
The
receiver of a TCP segment will check the field labeled "Acknowledgment
Number" whenever it receives a TCP segment in order to ascertain which
subsequent segment should be anticipated. Due to the fact that the receiver
confirms the reception of segments and notifies the sender about the next
anticipated sequence number, this makes it possible for data to be sent across
a TCP connection in a reliable and well-organized manner.
23. A Transmission Control Protocol
(TCP) connection is established and two devices ensure that they're speaking
the same protocol. What has occurred?
Answers
·
Four-way
handshake
·
Three-way handshake
·
Handwaving
·
Two-way
handshake
The TCP
Three-Way Handshake is a procedure in which two devices (for example, a client
and a server) exchange a sequence of three TCP segments in order to establish a
trustworthy connection prior to the beginning of the real data transfer. This
happens before the actual data transmission starts.
Answers
·
presentation layer
·
application
layer
·
session
layer
·
data
layer
It is the
responsibility of this component to ensure that the data transmitted and
received by applications is displayed in a way that is both legible and
useable. It handles things like character encoding, data compression, and
encryption and decryption, and it makes sure that the data at the application
layer is turned into a form that the program can comprehend.
The
Presentation Layer is responsible for managing these responsibilities, which
enables it to promote the interoperability of programs running on various
platforms and maybe using different data formats.
Answers
·
RST
·
SYN
·
FIN
·
PSH
When a
piece of hardware transmits a TCP segment with the RST flag set, it
communicates two things: it wishes to promptly terminate the connection, and it
communicates that there is an error situation. This flag is often set if a
device has an issue that prohibits it from continuing the conversation or
whenever it gets data that is either unexpected or malformed.
In a
nutshell, the RST flag in TCP is a mechanism to reset and terminate a
connection forcibly in the event that an error has occurred or there is no way
to recover from a challenging circumstance.
Answers
·
application
·
network
·
transport
·
data-link
HTTP is
the protocol that allows web browsers and web servers to communicate with one
another, which in turn makes it easier to send hypertext (formatted text,
pictures, videos, and so on) over the Internet. It functions at the application
layer since it is responsible for defining the manner in which apps (web
browsers and web servers) communicate and share information with one another.
The File
Transfer Protocol (FTP), the Simple Mail Transfer Protocol (SMTP), and the
Domain Name System (DNS) are a few further examples of protocols that belong to
the Application Layer. The connection between programs that are operating on
separate devices that are linked to a network is governed by these protocols,
which establish the rules for such communication.
Answers
·
10.1.1.150.80
·
10.1.1.150.21
·
10.1.1.150:21
·
10.1.1.150:80
Answers
·
Sequence number
·
Acknowledgement
number
·
Checksum
·
Urgent
pointer
When data
is broken up into segments for transmission, either because an Ethernet frame
can only hold so much information or for some other reason, the sequence
numbers play an important role in ensuring that the segments are sent in the
right order. Before transmitting the data to the higher-layer application, the
receiving TCP stack utilizes these sequence numbers to appropriately organize
and reassemble the segments in preparation for doing so.
Answers
·
seven
·
five
·
six
·
eight
Answers
·
reserved
·
ephemeral
·
registered
·
system
In most
cases, the number of ephemeral ports is selected from the range of 49152 to
65535. When a client first establishes a connection to a server, the operating
system will designate a free ephemeral port for the client to make use of
throughout the course of that particular session. This enables a number of
client apps to concurrently make connections to a number of different servers
without causing any issues.
Answers
·
Random
·
Prioritized
·
Largest
to smallest
·
Sequential
The
sequence numbers included inside the TCP header are absolutely necessary in
order to keep the segments in the right order. Before providing the data to the
higher-layer application, the receiving TCP stack utilizes these sequence
numbers to reassemble the segments in the appropriate order so that they may be
processed.
Therefore,
the sequence of transmitting and receiving TCP segments is normally retained,
which guarantees that the data is sent to the receiving application in the same
order that it was transmitted by the program that was sending it.
Answers
·
Socket
address
·
Demultiplexing
·
Multiplexing
·
File
Transfer
Each
communication endpoint (such as an application or service) is identified within
the context of the transport layer by a combination of an IP address and a port
number. This may be done in a variety of ways. The port number plays an
important role in ensuring that the incoming data is sent to the correct
receiving service on the destination node.
For instance, the port number in TCP (Transmission Control Protocol) and UDP (User Datagram Protocol) is a 16-bit field that has the potential value of anywhere between 0 and 65535. Port numbers that are well-known are set aside for certain services (for example, port 80 is used for HTTP, and port 21 is used for FTP), whereas port numbers that are dynamically issued or private are used for other reasons. Because of this, individual nodes are able to route traffic to the appropriate application or service depending on the port number.
33. Which field in a Transmission Control Protocol (TCP) header
is chosen from ephemeral ports?
Answers
·
Acknowledgement
number
·
Source port
·
Sequence
number
·
Destination
port
When a
client begins the process of establishing an outbound connection to a server,
the operating system of the client will normally choose an accessible ephemeral
port to act as the connection's source port. The number range used to choose
ephemeral ports is typically between 49152 and 65535. The TCP header contains
information that helps uniquely identify the communication endpoints for the
TCP connection. This information is comprised of the source port as well as the
destination port.
In a
nutshell, the Source Port field in the TCP header is determined by selecting a
port from a pool of ephemeral ports when client programs want to establish
outbound connections.
Answers
·
SYN_RECEIVED
·
LISTEN
·
SYN_SENT
·
ESTABLISHED
Explanation: When a Transmission
Control Protocol (TCP) connection is functioning properly and both parties are
able to communicate data to one another, the TCP socket state is said to be
"ESTABLISHED." In the TCP state diagram, the word "ESTABLISHED"
indicates that the TCP connection has been successfully established. At this
point, data may be sent in both directions between the devices that are
interacting with one another.
The client
and the server are both actively conversing with one another and exchanging
data packets across the connection that has been established at this point.
Once the TCP connection's three-way handshake has been completed and both ends
of the connection have recognized that it has been established, the connection
will enter this regular operating state.
35. If the checksum doesn't compute
for a packet sent at the Internet Protocol (IP) level, what will happen to the
data?
Answers
·
The data will be discarded
·
The
data will be sent back to the sending node with an error.
·
The
data will be resent
·
It
will be sent, but may be out of order.
When an IP
packet is received by a device, the device recalculates the checksum based on
the content of the packet and then compares this newly calculated checksum to
the checksum value that is given in the packet header. It is an indication that
the packet may have been corrupted while it was being sent if the checksum that
was computed does not match the one that was included in the header.
When this
occurs, the device that is doing the receiving makes the assumption that the
packet is unstable or has been tampered with and decides to throw it away. This
prevents the delivery of data that has been damaged or might possibly be
harmful, hence preserving the integrity of data transmission inside IP
networks.
Answers
·
FIN
·
RST
·
SYN
·
PSH
The Urgent
Pointer element indicates the location of the conclusion of the urgent data
included inside the TCP segment. It is common practice to make use of the URG
flag in combination with the Urgent Pointer when communicating to the receiving
application that certain data contained within the segment demands urgent
attention or must be given priority processing.
Answers
·
payload
·
footer
·
header
·
flags
This
application layer data must be segmented, encapsulated, and then transported to
its final destination via the transport layer. The application's real data,
known as the payload, is located in the data part of the transport layer
segment. This component of the segment is responsible for sending the data over
the network.
Answers
·
FINISHED
·
CLOSE_WAIT
·
FIN_WAIT
·
CLOSED
During the
process of closing a TCP connection, the connection will cycle through a number
of different states. These states include FIN_WAIT_1, FIN_WAIT_2, TIME_WAIT,
and others. When both ends of the connection have accepted that the connection
has been severed, it will eventually transition into the CLOSED state. At this
point, the socket will be made available for other uses.
In a
nutshell, the CLOSED state in TCP denotes that the socket has been closed and
is no longer accessible for any further transmission.
Answers
·
Acknowledgements
·
Approvals
·
Recognition
·
Verifiers
The sender
is responsible for sending data segments to the receiver in a
connection-oriented communication, and the receiver is responsible for sending
acknowledgments back to the sender to certify that they have successfully
received the data. In the event that a data segment is either misplaced or
fails to be correctly received, the sender will not get the anticipated
acknowledgment, and it will proceed to retransmit the data.
This
continuous back-and-forth of acknowledgments serves to assure the transmission
of data in a dependable and sequential manner. In the event that a segment is
not properly sent, the sender will continue to try sending it until the
recipient indicates that they have successfully received it. In
connection-oriented protocols, the use of this technique helps to avoid the
loss of data and assures that the information that is transferred is complete
and accurate.
Answers
·
high
five
·
two-way
handshake
·
three-way
handshake
·
four-way
handshake
41. What port does the File Transfer
Protocol (FTP) typically listen on?
Answers
·
80
·
21
·
25
·
443
The transport of data via FTP happens over a different channel, and extra ports are used for data connections depending on whether the mode is active or passive. On the other hand, port 21 is always used for the connection that controls the system and is where instructions and replies are traded.
You have 3 networks (A, B, and C) and 2 routers (Y and Z).
Network A has an address space of 10.1.1.0/24 and is connected to router Y, using the interface 10.1.1.1.
Network B has an address space of 192.168.1.0/24 and is connected to Router Y, using the interface 192.168.1.254. Network B is also connected with router Z, using the interface of 192.168.1.1.
Network C has an address space of 172.16.1.0/24 and is connected to router Z, using the interface 172.16.1.1. The diagram below represents these connections and interfaces.
Answers
·
Not
present
·
Network
C
·
Network A
·
Network
B
Answers
·
To obtain Router Y’s MAC address
·
To
verify the internet connection
·
To
obtain Computer 2 MAC address
·
To
calculate the TTL
Explanation: When a computer, which we
will refer to as Computer 1, sends a message using the Address Resolution
Protocol (ARP) with the target media access control (MAC) address of
FF:FF:FF:FF:FF:FF, that computer is broadcasting an ARP request to all of the
nodes that are connected to the network. This particular kind of ARP request is
referred to as a "broadcast ARP request."
This
broadcast ARP request has been sent out with the intention of locating the node
on the network whose MAC address corresponds to its IP address and learning
that information. To put it another way, Computer 1 is looking for the MAC
address that corresponds to a certain IP address, so it sends out a broadcast
ARP request to all of the nodes in the network, requesting the node that has
the IP address in question to reply with its MAC address.
The
resolution of IP addresses to MAC addresses is a process that is often used in
local area networks (LANs). This helps to ensure that devices on the same
network segment are able to interact with one another.
44. Which layer constructs the IP
datagram?
Answers
·
Physical
Layer
·
Application
layer
·
Network layer
·
Data
layer
Explanation: The "Network
Layer" is the layer that is responsible for constructing the IP datagram.
Within the framework of the Internet Protocol Suite, which is more often
referred to as TCP/IP, the Network Layer is in charge of the addressing and
routing of packets (or datagrams) between devices that are connected to various
networks.
The
Internet Protocol (IP) works at the Network Layer and is in charge of
encapsulating data from higher layers into IP datagrams. This function is
performed at the Network Layer. As the fundamental unit enabling the
transmission of data over IP networks, the IP datagram contains not only the IP
addresses of the sender and receiver but also various forms of control
information.
In
conclusion, the Network Layer is responsible for the construction of the IP
datagram, which makes the transmission of data between devices in a network
more simpler.
45. What information is in the data
payload of the Ethernet frame?
Answers
·
IP datagram
·
network
interface
·
ART
message
·
Handshake
In the
event that an Ethernet frame is transporting an IP packet, for instance, the
data payload would consist of the IP packet in its entirety, including both its
header and its payload. Likewise, if an Ethernet frame were conveying a TCP or
UDP segment, the data payload would comprise the whole of the segment,
including both the headers and the payload for the appropriate protocol.
The
Ethernet header, which contains the source and destination MAC addresses, an
EtherType field, and occasionally a VLAN tag, is the component that makes up
the structure of an Ethernet frame. After the header comes the data payload,
which may have a variety of different contents depending on the protocol that
is being conveyed inside the Ethernet frame.
Answers
·
Computer
2’s MAC address
·
Router
Y’s MAC address
·
Computer
1’s MAC address
·
Router Z’s MAC address
In the
header of an Ethernet frame, you'll find the MAC addresses for both the source
and the destination. The MAC address of the device that is providing the data,
in this case Router Y, is known as the source MAC address. The MAC address of
the device that is receiving the data, Router Z, is known as the destination
MAC address.
When the
Ethernet frame finally reaches Router Z, the network interface card (NIC) of
Router Z will verify the destination MAC address to determine whether or not
the frame is meant for it. This will allow Router Z to determine whether or not
the frame is intended for it. After it has been decapsulated, the IP packet
that is included inside the Ethernet frame will next be handled by the
networking stack that is located on Router Z.
Answers
· Sends an ARP broadcast message
·
Sends
back the packages to router Y for confirmation
·
Calculates
a checksum and compares this checksum with the one in the Ethernet frame header
·
Strips away the Ethernet frame, leaving the IP
datagram. Performs a checksum calculation against the entire datagram
Answers
·
0
·
61
·
65
·
63
Assuming
the packet goes via Router Z and another router in Network B on its way to
Computer 2 on Network C, the TTL value will be reduced by 2 because of this.
Answers
·
Source
Port: 80
Destination Port: 5000
Sequence Number: 1
Acknowledgment Number: 2
·
Source
Port: 5000
Destination Port: 80
Sequence Number: 1
Acknowledgment Number: 2
·
Source
Port: 8081
Destination Port: 50
Sequence Number: 4
Acknowledgment Number: 1
·
Source
Port: 80
Destination Port: 5000
Sequence Number: 1
Acknowledgment Number: 1
Explanation: This is the fundamental
data that must be provided for the first TCP segment. Additional fields such as
Sequence Number, Acknowledgment Number, Data Offset, Flags (such as the SYN
flag for the first connection), Window Size, Checksum, and Urgent Pointer would
be included in a genuine TCP segment. These fields would be included in a
legitimate TCP segment. The values for these variables would be determined by
the particulars of the TCP protocol as well as the communication that is
currently taking place.
50. Computer 1 on network A, with IP
address of 10.1.1.10, wants to send a packet to Computer 2, with IP address of
172.16.1.64. Which of the following has the correct IP datagram information for
the fields: Version, minimum Header Length, Source IP, and Destination IP?
Answers
·
Version:
5
Header Length: 16
Source IP Address: 171.1.1.1.
Destination IP address: 172.16.1.0/24.
·
Version:
6
Header Length: 20
Source IP Address: 8a:1a:2b:3c:4d:5f
Destination IP address: 2a:2b:3c:4d:8f
·
Version: 4
Header Length: 20
Source IP Address: 10.1.1.10
Destination IP address: 172.16.1.64
·
Version:
4
Header Length: 32
Source IP Address: 10.1.1.1
Destination IP address: 172.16.1.1
Answers
· network
identification
·
ethernet
port
·
router
velocity
·
cable plug
Explanation: When we talk about RJ45,
we are talking to a particular kind of connection that is often used for
Ethernet networking. RJ45 is an abbreviation that stands for "Registered
Jack 45," and it refers to a common connection that is used often in the process
of joining network cables, most notably in Ethernet networks.
The RJ45
connection is often used with twisted-pair cables and consists of eight
individual pins. It is used to terminate the ends of Ethernet cables, making it
possible for various pieces of networking equipment, including computers,
routers, switches, and others, to be linked to a network.
Ethernet
networking often makes use of Category 5 (Cat5), Category 5e (Cat5e), Category
6 (Cat6), and Category 6a (Cat6a) connections; hence, RJ45 connectors are
frequently used with these types of cables. A modular connection known as an
RJ45 connector may be crimped onto the end of a network cable to provide a
standardized interface for linking devices in a local area network (LAN). This
kind of connector is known as an RJ45 connector.
Shuffle Q/A 1
Answers
·
Network
C
·
Network
B
·
Not
present
·
Network A
Since this
is the case, Computer 2 is also connected to Network A. Since the devices are
part of the same network segment, they are able to engage in direct
communication with one another inside the same subnet without the intervention
of any routing protocols.
Answers
·
Port
number
·
MAC address
·
TTL
value
·
Destination
MAC address
In this
example, the gateway is often a router, which performs the function of acting
as an intermediate by routing packets across several networks. It is necessary
for Computer 1 to ascertain the MAC address of the interface on the router that
is linked to the local network (the default gateway). This is accomplished by
examining its ARP table, which contains a mapping of IP addresses to MAC
addresses.
Computer 1 will submit an ARP request to the local network in the event that the MAC address corresponding to the gateway's IP address is not already stored in the ARP table. The request will inquire about the MAC address that is associated with the gateway's IP address. As soon as it has the ARP reply including the MAC address, it is able to encapsulate the packet with the proper destination MAC address and then transmit it to the gateway so that it may be routed further.
54. Which layer constructs the Ethernet frame?
Answers
·
Data link layer
·
Application layer
·
Physical Layer
·
Transport layer
Explanation: The "Data Link Layer," more particularly the
"Ethernet sublayer," is the layer that is responsible for the
construction of the Ethernet frame. The Data Link Layer is subdivided into two
parts under the OSI model; these parts are referred to as the Logical Link
Control (LLC) sublayer and the Media Access Control (MAC) sublayer
respectively.
The framing of data for transmission across the physical
network media is the responsibility of Ethernet, which works at the Media
Access Control (MAC) sublayer of the Data Link Layer. The source and
destination MAC addresses, as well as data, are included inside an Ethernet
frame alongside an EtherType field.
In response to your inquiry, the Ethernet frame is built at
the Data Link Layer, more precisely at the Media Access Control (MAC) sublayer
that resides inside that layer.
55. Computer 1 on
network C, with IP address of 172.16.1.57, wants to send a packet to Computer
2, with IP address of 172.16.1.133. If the TTL value was set to 64 at the
beginning, what is the value of the TTL once it reaches its destination?
Answers
·
64
·
0
·
61
·
65
Explanation: When a packet is sent from Computer 1 to Computer 2 on
Network C, the Time-to-Live (TTL) value does not change because, under the
assumption that the computers are part of the same subnet or local network
(there are no routers involved), the value does not change. In most cases, the
TTL will decrease by one with each subsequent router hop.
When it reaches its destination, Computer 2, the TTL value will still be 64 if the computers are on the same subnet and there are no routers in the path. Because the packet does not go via any routers, the TTL field does not be decremented in this scenario. The TTL is normally dropped by one at each router hop to guarantee that the packet has a limited lifetime. This is done because the TTL is mainly used for the purpose of preventing packets from recirculating endlessly inside the network.
56. Computer 1 on
network B, with IP address of 192.168.1.233, wants to send a packet to Computer
2, with IP address of 172.16.1.133. Which of the following has the correct IP
datagram information for the fields: Version, minimum Header Length, Source IP,
and Destination IP?
Answers
·
Version: 4
Header Length: 20
Source IP Address: 192.168.233
Destination IP address: 172.16.1.133
·
Version: 5
Header Length: 16
Source IP Address: 10.1.1.0/24.
Destination IP address: 172.16.1.0/24.
·
Version: 4
Header Length: 32
Source IP Address: 10.1.1.1
Destination IP address:172.16.1.1
·
Version: 6
Header Length: 20
Source IP Address: 8a:1a:2b:3c:4d:5f
Destination IP address: 2a:2b:3c:4d:8f
57. The Cat6 cable is
part of the ______ layer.
Answers
·
Transport
·
Application
·
Physical
·
Network
Explanation: In the OSI model, the "Physical Layer" includes
the Cat6 cable as one of its components. The Physical Layer is the lowest layer
in the OSI (Open Systems Interconnection) paradigm. It is in charge of the
transmission and receipt of raw data bits across a physical media, such as
cables, connectors, and switches, and it is the layer that is responsible for
the Open Systems Interconnection.
Ethernet networks often make use of twisted pair cables of the Cat6 (Category 6) kind. Cat6 stands for "Category 6." It offers a larger bandwidth as well as improved performance in comparison to earlier category standards such as Cat5 or Cat5e. The properties of the physical connection, such as the kind of cable that is used, the connections, signaling, and the physical architecture of the network, are all defined by the Physical Layer of the OSI model.
58. What information is
computer 1 looking at in the ARP table on Router Y?
Answers
·
Destination MAC address
·
Port number
·
TTL value
·
MAC address
Explanation: When Computer 1 queries the Address Resolution Protocol
(ARP) database that is stored on Router Y, it is seeking for a mapping that
corresponds MAC addresses to IP addresses. To be more specific, Computer 1 is
looking for the Media Access Control address, also known as MAC address, that
corresponds to the IP address of its default gateway or the interface of the
router that is linked to its local network.
In the context of ARP, the table generally comprises
entries that connect IP addresses with the MAC addresses that are associated
with them. The ARP table provides the router with the information it needs to
correctly route data packets to the network's subsequent hops. When Computer 1
wishes to connect with devices that are not part of its local network, it sends
the packets to the default gateway, which is Router Y. In order to encapsulate
the packets appropriately so that they may be sent on the local network,
Computer 1 requires the MAC address of the router's interface.
In conclusion, Computer 1 is now consulting the ARP table that is stored on Router Y in order to locate the MAC address of the router's interface that acts as the default gateway for traffic coming from outside the local area network.
59. Computer 1 on
network C, with IP address of 172.16.1.57, wants to send a packet to Computer
2, with IP address of 192.168.1.14. Taking in consideration that computer 1 is
sending a request to a web server on computer 2, listening on port 80, and the source
port on computer 1 is 5000, which of the following contains the correct
information for the fourth TCP segment of data?
Answers
·
Source Port: 5000
Destination Port: 80
Sequence Number: 1
Acknowledgment Number: 2
·
Source Port: 8081
Destination Port: 50
Sequence Number: 4
Acknowledgment Number: 1
·
Source Port: 5000
Destination Port: 80
Sequence Number: 4
Acknowledgment Number: 5
·
Source Port: 80
Destination Port: 5000
Sequence Number: 1
Acknowledgment Number: 1
60. When constructing the Ethernet datagram to send the packet from
Router Z to Computer 2 which is on Network C, what information needs to be in
the destination MAC address?
Answers
·
Computer 2’s MAC address
·
Router Y’s MAC address
·
Computer 1’s MAC address
·
No MAC address is needed
Explanation: When an Ethernet datagram is being
constructed to transmit a packet from Router Z to Computer 2, which is on
Network C, the destination MAC address must be the MAC address of the network
interface card (NIC) of the next hop or the ultimate destination. This is
because the MAC address of the final destination is used to determine if the
packet was successfully delivered.
Assuming that the packet is being transmitted from Router Z
to Computer 2, Router Z has to know the media access control (MAC) address of
either Computer 2 or the next router along the way to Computer 2.
The MAC address of the network interface card (NIC) on the
device that is either the ultimate destination (Computer 2) or the next hop
router on the way toward Computer 2 will be the destination MAC address that is
included in the Ethernet frame. Before delivering the packet, this MAC address
is resolved using the Address Resolution Protocol, which helps establish its
location. If Router Z already has the MAC address, it will make use of that
information; otherwise, it will use ARP in order to locate it.
61. Computer 1 on
Network A sends a packet to Computer 2 on Network C. What's the last step that
Router Z does after receiving the Ethernet frame?
Answers
·
Sends back the packages to router Y
for confirmation
·
Decrements the TTL by 1,
calculates a new checksum, and makes a new IP datagram. This new IP datagram is
again encapsulated on a new Ethernet frame.
·
Strips away the Ethernet frame,
leaving the IP datagram. Performs a checksum calculation against the entire
datagram
·
Calculates a checksum and compares
this checksum with the one in the Ethernet frame header
62. Computer 1 on
network A, with IP address of 10.1.1.8, wants to send a packet to Computer 2,
with IP address of 172.16.1.64. If the TTL value was set to 64 at the
beginning, what is the value of the TTL once it reaches its destination?
Answers
·
65
·
60
·
0
·
62
Explanation: Assuming that the packet stays on the same local network
during its journey from Computer 1 to Computer 2, the Time-to-Live (TTL) number
will not change. This is because there will be no routers involved in this
scenario. The TTL value is reduced by one at each router hop; however, if the
devices are on the same subnet, there are no intervening routers; hence, the
TTL value is unaffected and stays unchanged.
Because of this, the TTL value will not change when it reaches its destination (Computer 2) on the same local network (Network A) if Computer 1 sends a packet to Computer 2 on that network. At each router hop, the TTL value is reduced, which serves the purpose of preventing data packets from traveling around the network in an unending loop. Since there are no routers involved in this scenario, the TTL does not change.
63. The ________ layer
is responsible for sending ones and zeros through a process called modulation
from Computer 1 to Computer 2.
Answers
·
Transport
·
Physical
·
Network
·
Application
Explanation: The "Physical Layer" is in charge of the
transmission of ones and zeros from Computer 1 to Computer 2 using a method
known as modulation. The transmission and receiving of raw binary data via a
physical media is the responsibility of the Physical Layer, which is the lowest
layer in the OSI (Open Systems Interconnection) paradigm.
The act of converting digital data into analog signals so
that it may be sent via a physical communication channel is referred to as
modulation. This layer is concerned with the actual physical connection between
devices, including the properties of the transmission medium, which might
include things like cables, connections, and the modulation methods that are
used for signaling.
In the context of computer networking, the Physical Layer is the layer that is responsible for ensuring that the bits created by higher layers are correctly sent across the physical channel and are received properly by the device that is doing the receiving.
64. If it’s a TCP
connection, which is the first segment that computer 1 needs to build?
Answers
·
IP datagram
·
handshake
·
TCP segment
·
Ethernet frame
65. What information is
in the payload section of the TCP segments?
Answers
·
The application layer data
·
ART Table
·
The MAC address of Computer 1
·
Handshake
Explanation: The
actual data that is being sent between the sender and the receiver is included
inside the payload part of TCP (Transmission Control Protocol) segments. When
discussing TCP, the payload is often referred to as the "data" or the
"application data." This is the data that the application layer
intends to convey, and it is cloaked in the TCP segment for protection.
Use the following
scenario to answer the 10 questions below:
You have 3 networks (A, B, and C) and 2 routers (Y and Z).
Network A has an address space of 10.1.1.0/24 and is connected to router Y,
using the interface 10.1.1.1.
Network B has an address space of 192.168.1.0/24 and is connected to Router Y,
using the interface 192.168.1.254. Network B is also connected with router Z,
using the interface of 192.168.1.1.
Network C has an address space of 172.16.1.0/24 and is connected to router Z,
using the interface 172.16.1.1. The diagram below represents these connections
and interfaces.
66. Computer 1 on
network A, with IP address of 10.1.1.205, wants to send a packet to Computer 2,
with IP address of 172.16.1.57. On which network is computer 2?
Answers
·
Network A
·
Network B
·
Local network
· Network C