02 - Networks and The Internet | 03. Introduction To Network Basics Flashcards
1
Q
How are we able to access context online?
A
Networking
2
Q
Your device uses a _________ connection and goes through a series of defined ________ protocols to send and receive information.
A
NETWORK
3
Q
What is a network?
A
A network is two or more computers or devices that are linked in order to share information.
4
Q
Why are our computers and devices able to communicate?
A
Our computers and devices are able to communicate due to a large set of standards, much like we have road systems and traffic protocols when we drive a car. These network standards have been built by the community over the decades, and these standards guide engineers and security professionals.
5
Q
When we talk about a network that could be anything connecting ______________ devices.
A
TWO OR MORE
6
Q
Networks are broken into subsets based on what?
A
Based on their SIZE and FUNCTION
7
Q
What are the most common network types?
A
- LAN
- CAN
- WAN
8
Q
What is a CAN?
A
A Campus Area Network (CAN) connects multiple computers and devices over a slightly larger area. In many cases, these types of networks will connect multiple buildings located in the same vicinity. You may see these networks in a university where multiple buildings and outdoor spaces provide students with network access.
9
Q
What is a LAN?
A
A Local Area Network (LAN) is a smaller network that connects multiple devices in a limited area. Examples of LANs include small offices, a home, or any other network contained within a small area.
10
Q
What is a WAN?
A
A Wide Area Network (WAN) connects multiple computers over a geographically large area. Large, international organizations may operate these types of networks. To ensure that computers spread over large regions are able to communicate, companies may use a VPN (Virtual Private Network) to connect systems securely. A VPN can allow systems across large regions to connect and interact with one another on the same network.
11
Q
Is the internet classified as a LAN, CAN, or WAN?
A
WAN
12
Q
What does OSI Model stand for?
A
Open Systems Interconnection Model
13
Q
When was OSI Model made and what is it for?
A
The OSI (Open Systems Interconnection) Model was developed in the 1970s and 1980s, and it is a conceptual model that breaks networking into seven separate layers. Each layer refers to a set of functions that are responsible for specific tasks.
The layers start from physical signals all the way up to the web applications we interact with. Each layer generally only interacts with the layer below it and provides useful tools or information to the layer above it.
14
Q
Why is OSI helpful?
A
OSI is used to help us categorize network processes so we can communicate about them during troubleshooting and while improving security.
15
Q
How many layers are in the OSI model?
A
7
16
Q
What are the seven layers to the OSI model from bottom to top?
A
- Physical (ethernet cables, bluetooth, modem, repeater)
- Data Link (data frames, MAC addresses)
- Network (Data Packets, Routing)
- Transport (Data Delivery & Transport Protocol, Error Inspection)
- Session (Session Management, Session ID, Time Left)
- Presentation (En/decrypting & Presenting Data)
- Application (End User Applications)
PDLNTSPA
17
Q
What is the 1st layer of the OSI model?
A
The physical layer
18
Q
What does the Physical Layer in OSI do?
A
The Physical, and lowest layer of the model, covers how unstructured data, like bits, is transmitted. Some concrete examples of this are the ways wires are configured, the way signals are transferred over those wires, and the radio frequencies computers use.
The lowest layer of the OSI reference model is the physical layer. It is responsible for the actual physical connection between the devices. The physical layer contains information in the form of bits. It is responsible for transmitting individual bits from one node to the next. When receiving data, this layer will get the signal received and convert it into 0s and 1s and send them to the Data Link layer, which will put the frame back together.
19
Q
What are technologies that are commonly used in the Physical layer in OSI?
A
Technology such as WiFi, Bluetooth, and cable standards such as CAT5 and CAT6 all operate at this layer.
This layer also includes the hardware part of modems, adapters, and repeaters.
Hub, Repeater, Modem, and Cables are Physical Layer devices.
Network Layer, Data Link Layer, and Physical Layer are also known as Lower Layers or Hardware Layers.
20
Q
What is the Physical layer doing functionally in OSI?
A
Over these wires and signals, the raw data bits are received as a stream of 0s and 1s. Fixing errors that occur just at this layer means considering physical damage or interference.
- Bit Synchronization: The physical layer provides the synchronization of the bits by providing a clock. This clock controls both sender and receiver thus providing synchronization at the bit level.
- Bit Rate Control: The Physical layer also defines the transmission rate i.e. the number of bits sent per second.
- Physical Topologies: Physical layer specifies how the different, devices/nodes are arranged in a network i.e. bus, star, or mesh topology.
- Transmission Mode: Physical layer also defines how the data flows between the two connected devices. The various transmission modes possible are Simplex, half-duplex and full-duplex.
21
Q
What is the layer above and below the Physical layer in OSI?
A
Below: Nothing
Above: Data Link
22
Q
What is the 2nd layer of the OSI model?
A
The Data Link Layer
23
Q
What does the Data Link Layer in OSI do?
A
The Data Link layer covers how data is sent from device to device when they are connected on the same local network.
The data link layer is responsible for the node-to-node delivery of the message. The main function of this layer is to make sure data transfer is error-free from one node to another, over the physical layer. When a packet arrives in a network, it is the responsibility of the DLL to transmit it to the Host using its MAC address.
24
Q
What are technologies that are commonly used in the Data Link layer in OSI?
A
It involves physical addresses of devices, called Media Access Control (MAC) address. All devices have a unique 48-bit MAC address where the first 24 bits relate to the manufacturer, and the last 24 bits make it unique to each device.
The Data Link Layer is divided into two sublayers:
Logical Link Control (LLC)
Media Access Control (MAC)
The packet received from the Network layer is further divided into frames depending on the frame size of the NIC(Network Interface Card). DLL also encapsulates Sender and Receiver’s MAC address in the header.
The Receiver’s MAC address is obtained by placing an ARP(Address Resolution Protocol) request onto the wire asking “Who has that IP address?” and the destination host will reply with its MAC address.
25
What is the Data Link Layer doing functionally in OSI?
It structures incoming or outgoing data bits into data frames.
It routes data frames to the correct physical addresses. A switch (could be your computer or router) keeps track of local devices and their MAC addresses and makes sure data frames get to the correct physical location.
It ensures the flow of data is synchronized between devices, so data doesn’t jam up the memory of a slow receiving physical device.
It detects errors within data frames. This involves a system of error control!
1. Framing: Framing is a function of the data link layer. It provides a way for a sender to transmit a set of bits that are meaningful to the receiver. This can be accomplished by attaching special bit patterns to the beginning and end of the frame.
2. Physical Addressing: After creating frames, the Data link layer adds physical addresses (MAC addresses) of the sender and/or receiver in the header of each frame.
3. Error Control: The data link layer provides the mechanism of error control in which it detects and retransmits damaged or lost frames.
4. Flow Control: The data rate must be constant on both sides else the data may get corrupted thus, flow control coordinates the amount of data that can be sent before receiving an acknowledgment.
5. Access Control: When a single communication channel is shared by multiple devices, the MAC sub-layer of the data link layer helps to determine which device has control over the channel at a given time.
Packet in the Data Link layer is referred to as Frame.
Data Link layer is handled by the NIC (Network Interface Card) and device drivers of host machines.
Switch & Bridge are Data Link Layer devices.
26
What is the layer above and below the Data Link layer in OSI?
Below: Physical
Above: Network
27
What do we see beginning to happen with layers 3 and 4 in the OSI model?
In layers 3 and 4, we begin to see how data is routed between different networks and how transportation protocols function within these layers.
28
What is the 3rd layer of the OSI model?
Network
29
What does the Network Layer in OSI do?
The Network layer describes how data packets are routed between wider networks such as the Internet.
The network layer works for the transmission of data from one host to the other located in different networks. It also takes care of packet routing i.e. selection of the shortest path to transmit the packet, from the number of routes available. The sender & receiver’s IP addresses are placed in the header by the network layer.
30
What are technologies that are commonly used in the Network layer in OSI?
Whereas a data frame at the data link layer travels to local MAC addresses, a data packet at the network layer is routed from a source IP (Internet Protocol) address to a destination IP address.
Segment in the Network layer is referred to as Packet.
Network layer is implemented by networking devices such as routers and switches.
31
What is the Network Layer doing functionally in OSI?
Think of a data packet as an envelope. IP addresses are assigned to every computer or device connected to the Internet, and these addresses are formatted into four numbers each ranging from 0 to 255.
Example: 192.168.0.1
At this layer, there are routing protocols designed to help packets (aka, our envelopes) get from point A to point B as quickly as possible over the Internet. Your nearest router is one of the many routers connected to the Internet that help packets find where they need to go!
Functions of the Network Layer
1. Routing: The network layer protocols determine which route is suitable from source to destination. This function of the network layer is known as routing.
2. Logical Addressing: To identify each device inter-network uniquely, the network layer defines an addressing scheme. The sender & receiver’s IP addresses are placed in the header by the network layer. Such an address distinguishes each device uniquely and universally.
32
What is the layer above and below the Network layer in OSI?
Below: Data Link
Above: Transport
33
What is the 4th layer of the OSI model?
Transport
34
What does the Transport Layer in OSI do?
The Transport layer refers to how data is actually transferred.
The transport layer provides services to the application layer and takes services from the network layer. The data in the transport layer is referred to as Segments. It is responsible for the end-to-end delivery of the complete message. The transport layer also provides the acknowledgment of the successful data transmission and re-transmits the data if an error is found.
Services Provided by Transport Layer:
Connection-Oriented Service
Connectionless Service
1. Connection-Oriented Service: It is a three-phase process that includes:
Connection Establishment
Data Transfer
Termination/disconnection
In this type of transmission, the receiving device sends an acknowledgment, back to the source after a packet or group of packets is received. This type of transmission is reliable and secure.
2. Connectionless service:
It is a one-phase process and includes Data Transfer. In this type of transmission, the receiver does not acknowledge receipt of a packet. This approach allows for much faster communication between devices. Connection-oriented service is more reliable than connectionless Service.
35
What are technologies that are commonly used in the Transport layer in OSI?
The most common transport protocols on the Internet are TCP (Transmission Control Protocol) and UDP (User Datagram Protocol).
Data in the Transport Layer is called Segments.
Transport layer is operated by the Operating System. It is a part of the OS and communicates with the Application Layer by making system calls.
The transport layer is called as Heart of the OSI model.
Device or Protocol Use : TCP, UDP NetBIOS, PPTP
36
What is the Transport Layer doing functionally in OSI?
The Transport layer refers to how data is actually transferred. Let’s say you wanted to upload a photo from your phone onto social media. The transport layer handles how the image data from that photo is split (segmentation), the rate at which the packets are sent, and how errors are handled if data packets don’t make it to the site’s server.
Functions of the Transport Layer
1. Segmentation and Reassembly: This layer accepts the message from the (session) layer, and breaks the message into smaller units. Each of the segments produced has a header associated with it. The transport layer at the destination station reassembles the message.
2. Service Point Addressing: To deliver the message to the correct process, the transport layer header includes a type of address called service point address or port address. Thus by specifying this address, the transport layer makes sure that the message is delivered to the correct process.
37
What is the layer above and below the Transport layer in OSI?
Below: Network
Above: Session
38
What is the 5th layer of the OSI model?
Session
39
When two computers or devices have started an exchange of information, we call that what?
A Session
40
What does the Session Layer in OSI do?
The Session layer in OSI is responsible for opening, closing, and maintaining sessions.
This layer is responsible for the establishment of connection, maintenance of sessions, and authentication, and also ensures security.
41
What are technologies that are commonly used in the Session layer in OSI?
In terms of opening and closing, the session layer includes authentication and authorization measures. For example, without logging in or having the right permissions, you may not be able to connect to parts of a website. But if you are logged in, your access permission is stored for a set amount of time, or session length.
All the below 3 layers(including Session Layer) are integrated as a single layer in the TCP/IP model as the “Application Layer”.
Implementation of these 3 layers is done by the network application itself. These are also known as Upper Layers or Software Layers.
Device or Protocol Use : NetBIOS, PPTP.
42
What is the Session Layer doing functionally in OSI?
Meanwhile, session management ensures communications occur successfully by providing safeguards in case a connection fails or drops.
Functions of the Session Layer
1. Session Establishment, Maintenance, and Termination: The layer allows the two processes to establish, use, and terminate a connection.
2. Synchronization: This layer allows a process to add checkpoints that are considered synchronization points in the data. These synchronization points help to identify the error so that the data is re-synchronized properly, and ends of the messages are not cut prematurely and data loss is avoided.
3. Dialog Controller: The session layer allows two systems to start communication with each other in half-duplex or full-duplex.
Let us consider a scenario where a user wants to send a message through some Messenger application running in their browser. The “Messenger” here acts as the application layer which provides the user with an interface to create the data. This message or so-called Data is compressed, optionally encrypted (if the data is sensitive), and converted into bits (0’s and 1’s) so that it can be transmitted.
43
What is the layer above and below the Session layer in OSI?
Below: Transport
Above: Presentation
44
What is the 6th layer of the OSI model?
Presentation
45
What does the Presentation Layer in OSI do?
The presentation layer is also called the Translation layer. The data from the application layer is extracted here and manipulated as per the required format to transmit over the network.
46
What are technologies that are commonly used in the Session layer in OSI?
Device or Protocol Use: JPEG, MPEG, GIF.
47
What is the Presentation Layer doing functionally in OSI?
Functions of the Presentation Layer
1. Translation: For example, ASCII to EBCDIC.
2. Encryption/ Decryption: Data encryption translates the data into another form or code. The encrypted data is known as the ciphertext and the decrypted data is known as plain text. A key value is used for encrypting as well as decrypting data.
3. Compression: Reduces the number of bits that need to be transmitted on the network.
48
What is the layer above and below the Presentation layer in OSI?
Below: Session
Above: Application
49
What is the 7th layer of the OSI model?
Application
50
What does the Application layer in OSI do?
The final layer of the OSI model is the Application layer. This layer includes websites, browsers, email, mobile applications, and how they render Internet data so that we can interact with it.
At the very top of the OSI Reference Model stack of layers, we find the Application layer which is implemented by the network applications. These applications produce the data to be transferred over the network. This layer also serves as a window for the application services to access the network and for displaying the received information to the user.
51
What are technologies that are commonly used in the Application layer in OSI?
Example: Application – Browsers, Skype Messenger, etc.
Note: The application Layer is also called Desktop Layer.
Device or Protocol Use : SMTP.
52
What is the Application layer doing functionally in OSI?
The main functions of the application layer are given below.
1. Network Virtual Terminal(NVT): It allows a user to log on to a remote host.
2. File Transfer Access and Management(FTAM): This application allows a user to
access files in a remote host, retrieve files in a remote host, and manage or
control files from a remote computer.
3. Mail Services: Provide email service.
4. Directory Services: This application provides distributed database sources
and access for global information about various objects and services.
53
What is the layer above and below the Application layer in OSI?
Below: Presentation
Above: N/A
54
T/F | The OSI Model isn’t the only model that describes networking.
TRUE
55
How many layers are in the TCP/IP Model?
4
56
What are the layers in the TCP/IP Model?
1. Network Access Layer (includes physical and data link from OSI)
2. Internet Layer (same as network layer in OSI)
3. Transport Layer (same as transport layer in OSI)
4. Application Layer (includes session, presentation, and application from OSI)
57
What is the Application layer in TCP/IP Model?
This includes the opening and closing of sessions, translating data, and the interaction with content at the application level. Here, there are multiple protocols for web content, email, and accessing files, including HTTP, FTP, SMTP, and more.
58
What is the Transport layer in TCP/IP Model?
TCP and UDP are the core protocols here.
TCP is a connection-oriented protocol, where a more rigorous acknowledgment between one sender and one receiver must happen before any data can be sent. This protocol also includes flow control and error recovery, and it is used when larger amounts of data need to be sent and timing is less of a concern.
UDP is a more lightweight protocol that does not require a fixed channel between a sender and receiver. It is often used when the amount of data sent is piecemeal and needs to be transmitted quickly.
59
What is the Internet layer in TCP/IP Model?
This is where IP addressing and routing occur.
60
What is the Network Access layer in TCP/IP Model?
Sometimes called the Link layer, this layer encompasses the sending or receiving of network data at the local network level.
61
What are some key differences between OSI vs TCP/IP Model?
TCP/IP protocol ( Transfer Control Protocol/Internet Protocol ) was created by U.S. Department of Defense’s Advanced Research Projects Agency (ARPA) in 1970s.
Some key differences between the OSI model and the TCP/IP Model are:
1. TCP/IP model consists of 4 layers but OSI model has 7 layers. Layers 5,6,7 of the OSI model are combined into the Application Layer of TCP/IP model and OSI layers 1 and 2 are combined into Network Access Layers of TCP/IP protocol.
2. The TCP/IP model is older than the OSI model, hence it is a foundational protocol that defines how should data be transferred online.
3. Compared to the OSI model, the TCP/IP model has less strict layer boundaries.
4. All layers of the TCP/IP model are needed for data transmission but in the OSI model, some applications can skip certain layers. Only layers 1,2 and 3 of the OSI model are necessary for data transmission.
OSI-vs-TCP/IP
62
Why does the OSI model matter?
Even though the modern Internet doesn’t strictly use the OSI Model (it uses a simpler Internet protocol suite), the OSI Model is still very helpful for solving network problems. Whether it’s one person having trouble getting their laptop online, or a website being down for thousands of users, the OSI Model helps to identify the problem. If you can narrow down the issue to one specific layer of the model, you can avoid a lot of unnecessary work.
63
What are the advantages of the OSI model?
The OSI Model defines the communication of a computing system into 7 different layers. Its advantages include:
1. It divides network communication into 7 layers which makes it easier to understand and troubleshoot.
2. It standardizes network communications, as each layer has fixed functions and protocols.
3. Diagnosing network problems is easier with the OSI model.
4. It is easier to improve with advancements as each layer can get updates separately.
64
What are the disadvantages of the OSI model?
Disadvantages of OSI Model
1. Complexity: The OSI Model has seven layers, which can be complicated and hard to understand for beginners.
2. Not Practical: In real-life networking, most systems use a simpler model called the Internet protocol suite (TCP/IP), so the OSI Model isn’t always directly applicable.
3. Slow Adoption: When it was introduced, the OSI Model was not quickly adopted by the industry, which preferred the simpler and already-established TCP/IP model.
4. Overhead: Each layer in the OSI Model adds its own set of rules and operations, which can make the process more time-consuming and less efficient.
5. Theoretical: The OSI Model is more of a theoretical framework, meaning it’s great for understanding concepts but not always practical for implementation.
65
Is OSI layer still used?
Yes, the OSI model is still used by networking professionals to understand data abstraction paths and processes better.
66
What is the highest layer of the OSI model?
Layer 7 or Application layer is highest layer of OSI model.
67
What is layer 8?
Layer 8 doesn’t actually exist in the OSI model but is often jokingly used to refer to the end user. For example: a layer 8 error would be a user error.
68
What are network protocols?
They are simply a set of standards for devices interacting on the Internet! It’s important to understand these protocols from the angle of network security. Threat actors often abuse the rules of a protocol to gain access to sensitive information.
69
What are common network protocols?
DNS
HTTP
EMAIL - IMAP
EMAIL - POP
EMAIL - STMP
70
What does DNS stand for and what does it do?
The Domain Name System (DNS) protocol converts domain names to IP addresses. Think of it as a phonebook for the Internet. It’s hard to remember an exact IP address when we want to access a website. When we request the URL codecademy.com, our computer sends a DNS request to a DNS server. The server then returns the correct IP addresses to route data to and from Codecademy.
71
What does HTTP stand for and what does it do?
The HTTP (The Hyper Text Transfer Protocol) handles our web requests to servers. HTTP uses a set of verbs, like GET, POST, PUT, and HEAD, to retrieve and send data. Anytime a page is loaded, there are multiple web requests to retrieve content like images, text, and formatting code.
72
What does IMAP stand for and what does it do?
IMAP (Internet Message Access Protocol) and POP (Post Office Protocol) allow users to access emails stored on a remote web server. In IMAP, servers store your email and return copies to you, allowing you to access the same email on multiple devices.
73
What does POP stand for and what does it do?
In POP3 (POP version 3), however, emails are generally downloaded from the server onto just a single device.
74
What does SMTP stand for and what does it do?
To send email, the standard is SMTP (Simple Mail Transfer Protocol).
75
How do data packets get routed to these network services from the transport layer?
Specific numbers called ports are reserved so that packets for different services can come in at the same time. Think of ports as lanes for network traffic!
75
What is the network protocol, transport protocol, and port number for the network protocols involved in everyday internet activity?
NAME, TRANSPORT PROTOCOL, PORT NUMBER
1. DNS, TCP/UDP, 53
2. HTTP, TCP, 80/8080
3. EMAP, TCP, 143
4. POP3, TCP, 110
5. SMTP, TCP, 25/587
76
What are some common application layer protocols that are more commonly used by IT professionals?
1. SSH
2. FTP
3. SMB
Again, these are some of the protocols that are most often used and configured by IT professionals. They are central to the behind-the-scenes work of maintaining the web.
77
What does SSH stand for and what does it do?
Secure Shell (SSH) is used to access a remote terminal or virtual machine (VM) over a secure connection. IT professionals and engineers use this to help configure and program a system remotely and securely. For example, accessing Github from the command line uses SSH!
78
What does FTP stand for and what does it do?
The File Transfer Protocol (FTP) is used to transfer files from one system to another. Modern implementations of FTP can include encryption as well.
79
What does SMB stand for and what does it do?
The Server Message Block (SMB) protocol allows multiple users to interact with a remote system like a file share or printing services. Multiple people can view and modify shared resources and files in a centralized server.
80
Which of the following is a valid IP address?
1. 530.108.259.78
2. 01-D0-52-F2-B2-12
3. codeacademy.com
4. 192.54.22.190
4. 192.54.22.190
A valid IP address has four numbers that each range from 0 to 255.
81
A network is ____ or more computers or devices that are linked in order to share information.
1. two
2. one
3. ten
4. three
1. two
82
_____ is a connection-oriented transport protocol, where acknowledgment between one sender and one receiver must happen before any data can be sent. It also includes flow control and error recovery, and is used when larger amounts of data needs to be sent and timing is less of a concern.
TCP
82
_____ is used to access a remote terminal or virtual machine (VM) over a secure connection. Used often by IT professionals and engineers to program.
SSH
83
_____ is a transport protocol that does not require a fixed channel between a sender and receiver. It is often used when the amount of data sent is piecemeal and needs to be transmitted quickly.
UDP
84
_____ handles our web requests to servers. The protocol uses a set of verbs, like GET, POST, PUT, and HEAD, to retrieve and send data.
HTTP
85
_____ allow users to access emails stored on a remote web server and downloads emails from the server onto one device.
POP3
86
_____ converts domain names to IP addresses.
DNS
87
T/F | Once data hits the Network Layer with an IP address destination, pieces of data are formatted and referred to as data packets. Data frames are groups of data bits at the Data-Link layer that need to be routed to the correct physical location.
TRUE
88
What is the difference between the OSI Model of networking and the TCP/IP Model?
1. The OSI Model is a conceptual model that is neutral to implementations of specific network protocols and infrastructure.
2. The TCP/IP model is essential for this century, while the OSI Layer is old and irrelevant.
3. The TCP/IP is a conceptual model that is neutral to implementations of specific network protocols and infrastructure. The OSI model makes direct references to the current Internet implementation.
1. The OSI Model is a conceptual model that is neutral to implementations of specific network protocols and infrastructure.
TCP/IP is the model that makes direct reference to the current Internet implementation, while the OSI model is the more conceptual one.
89
T/F | Every device that can be connected to a network, whether it’s a phone or wireless speaker, has a unique MAC address.
TRUE
Unfortunately, it’s true! Every device has a unique MAC address. The first half relates to the manufacturer, and the last half make it unique to each device.
90
Which of the following isn’t a network protocol in the Application Layer of TCP/IP?
1. DNS
2. UDP
3. FTP
4. HTTP
2. UDP
Correct. This protocol lives in the Transport Layer. UDP is a lightweight protocol that does not require a fixed channel between a sender and receiver, and this transport protocol is used when the amount of data sent is small and needs to be sent quickly in bursts.
91
Which of the following is not a type of network?
1. WAN
2. IAN
3. CAN
4. LAN
2. IAN (Island Area Network)
You’re right! This isn’t a term we use to describe a type of network. A decent-sized type of network could connect a whole island though!
92
Which of the following could be part of the OSI Physical Layer of networking?
1. Bluetooth
2. Decryption of the data inside a packet
3. IP Addresses
4. MAC Address
1. Bluetooth
Yes, this technology involves physical signals, so the transfer of data via Bluetooth is considered part of the Physical Layer.
93
The non-profit trade association, CompTIA, recommends what following steps when a problem arises?
1. Identify the issue.
2. Research the problem.
3. Establish a theory of probable cause.
4. Test this theory to determine the cause.
5. Establish a plan of action and identify possible issues.
6. Implement this plan of action.
7. Verify full system functionality and implement preventative measures.
8.Document findings, actions, and outcomes.
94
What are the main questions for each step of the troubleshooting method?
And with that the Internet connection has been repaired! Here is an overview of the main questions for each step of the troubleshooting method:
1. Identify the issue: What is not working as expected?
2. Research the problem: What exactly happened when the error occurred?
3. Establish a theory of probable cause: What are the most common reasons this issue could have occurred?
4. Test this theory to determine the cause: What is the root cause?
5. Establish a plan of action and identify possible issues: What steps need to be taken to resolve the issue?
6. Implement this plan of action: Execute the planned steps.
7. Verify full system functionality and implement preventative measures: Does everything now work as expected? What can be done to prevent this issue in the future?
8. Document findings, actions, and outcomes: Leave your future self and any other interested parties notes on this issue and its solution.
95
What layer includes websites, browsers, emails, and methods of rendering data to become interactive.
Application Layer
96
What layer converts between raw data and format usable by an application, and handles encryption, encoding, and compression.
Presentation Layer
97
What layer determines the opening and closing of "sessions", ensures communication occurs successfully even when connection fails
Session Layer
98
What layer handles how data is portioned into packets, the rate at which packets are sent, and what happens when packets don't make it to their destination.
Transport Layer
99
What layer describes how data packets are routed from one IP address to another. Includes routing protocols to optimize the path of a packet.
Network Layer
100
What layer mediates the network layer and physical layer at a local network level. Involves the physical addressing (MAC address) of devices, and the flow of raw data to correct physical location.
Data Link Layer
101
What layer includes wires, signals, frequencies, and hardware. Here, data is 0's and 1's.
Physical Layer
