Module 1 - 03-2 Flashcards
Network communication
Pieces of data are typically referred to as?
Data packets
Define Data packet
A basic unit of information that travels from one device to another within a network
Give an example and briefly explain a Data Packet
A data packet is very similar to a physical letter. It contains a header that includes the internet protocol address, the IP address, and the media access control, or MAC, address of the destination device. It also includes a protocol number that tells the receiving device what to do with the information in the packet. Then there’s the body of the packet, which contains the message that needs to be transmitted to the receiving device. Finally, at the end of the packet, there’s a footer, similar to a signature on a letter, the footer signals to the receiving device that the packet is finished.
What is included in the Header of a Data Packet?
The Header includes the internet protocol address, the IP address, and the media access control, or MAC, address of the destination device. It also includes a protocol number that tells the receiving device what to do with the information in the packet.
What is included in the Body of a Data Packet?
The Body of the packet contains the message that needs to be transmitted to the receiving device.
What is included in the Footer of a Data Packet?
The footer signals to the receiving device that the packet is finished.
The movement of data packets across a network can provide an indication of how well the ___.
network is performing
Network performance can be measured by?
Bandwidth
Define Bandwidth
The amount of data a device receives every second
How can you calculate Bandwidth?
You can calculate bandwidth by dividing the quantity of data by the time in seconds
Define Speed
The rate at which data packets are received or downloaded
Why are security personnel interested in network bandwidth and speed?
If either are irregular, it could be an indication of an attack.
Define Packet sniffing
The practice of capturing and inspecting data packets across the network
What communication protocol do devices use to communicate with each other across the internet?
TCP/IP model
What does TCP/IP stand for?
Transmission Control Protocol and Internet Protocol (TCP/IP)
What is the TCP/IP model
A framework that is used to visualize how data is organized and transmitted across the network.
The standard model used for network communication
This model helps network engineers and network security analysts conceptualize processes on the network and communicate where disruptions or security threats occur.
The TCP/IP model combines multiple layers of the OSI model. There are many similarities between the two models. Both models define standards for networking and divide the network communication process into different layers. The TCP/IP model is a simplified version of the OSI model.
What dose TCP stand for?
Transmission Control Protocol (TCP)
Define TCP
An internet communication protocol that allows two devices to form a connection and stream data
Briefly explain TCP
The protocol includes a set of instructions to organize data, so it can be sent across a network. It also establishes a connection between two devices and makes sure that packets reach their appropriate destination.
What dose IP stand for?
Internet Protocol (IP)
Define TCP
A set of standards used for routing and addressing data packets as they travel between devices on a network
Briefly explain IP
Included in the Internet Protocol (IP) is the IP address that functions as an address for each private network.
When data packets are sent and received across a network, they are assigned a ____.
port
Define Port
A software-based location that organizes the sending and receiving of data between devices on a network
Briefly explain and give an example of a Port
Ports divide network traffic into segments based on the service they will perform between two devices. The computers sending and receiving these data segments know how to prioritize and process these segments based on their port number.
This is like sending a letter to a friend who lives in an apartment building. The mail delivery person not only knows how to find the building, but they also know exactly where to go in the building to find the apartment number where your friend lives.
Data packets include instructions that tell the receiving device what to do with the information. These instructions come in the form of a port number. Port numbers allow computers to split the network traffic and prioritize the operations they will perform with the data.
What is Port 25 used for?
What is Port 443 used for?
Secure internet communication
What is Port 20 used for?
Large file transfers
Which Port is used for E-mail?
Port 25
Which Port is used for Secure internet communication?
Port 443
Which Port is used for Large file transfers?
Port 20
How many layers does the TCP/IP model have?
Four (4)
What are the layers of the TCP/IP model?
1) Network access layer
2) Internet layer
3) Transport layer
4) Application layer
What is the first (1st) layer of the TCP/IP model?
1) Network access layer
(sometimes called the Data link layer)
What is the second (2nd) layer of the TCP/IP model?
2) Internet layer
(sometimes referred to as the Network layer)
What is the third (3rd) layer of the TCP/IP model?
3) Transport layer
What is the fourth (4th) layer of the TCP/IP model?
4) Application layer
Define and briefly explain the Network access layer of the TCP/IP model
The network access layer deals with creation of data packets and their transmission across a network.
This includes hardware devices connected to physical cables and switches that direct data to its destination.
Define and briefly explain the Internet access layer of the TCP/IP model
The internet layer is where IP addresses are attached to data packets to indicate the location of the sender and receiver.
The internet layer also focuses on how networks connect to each other. For example, data packets containing information that determine whether they will stay on the LAN or will be sent to a remote network, like the internet.
Define and briefly explain the Transport layer of the TCP/IP model
Includes protocols to control the flow of traffic across a network.
These protocols permit or deny communication with other devices and include information about the status of the connection. Activities of this layer include error control, which ensures data is flowing smoothly across the network.
Define and briefly explain the Application layer of the TCP/IP model
Protocols determine how the data packets will interact with receiving devices.
Functions that are organized at application layer include file transfers and email services.
Explain the Network access layer of the TCP/IP model
The network access layer, sometimes called the data link layer, deals with the creation of data packets and their transmission across a network.
This layer corresponds to the physical hardware involved in network transmission. Hubs, modems, cables, and wiring are all considered part of this layer. The address resolution protocol (ARP) is part of the network access layer. Since MAC addresses are used to identify hosts on the same physical network, ARP is needed to map IP addresses to MAC addresses for local network communication.
What does ARP stand for?
Address Resolution Protocol (ARP)
What layer of the TCP/IP model is the Address Resolution Protocol (ARP) part of?
Network access layer
Explain the Internet layer of the TCP/IP model
The internet layer, sometimes referred to as the network layer, is responsible for ensuring the delivery to the destination host, which potentially resides on a different network.
It ensures IP addresses are attached to data packets to indicate the location of the sender and receiver. The internet layer also determines which protocol is responsible for delivering the data packets and ensures the delivery to the destination host.
What are some common protocols that operate in the Internet layer of the TCP/IP model (2)?
- Internet Protocol (IP)
- Internet Control Message Protocol (ICMP)
What does IP stand for?
Internet Protocol (IP)
What does ICMP stand for?
Internet Control Message Protocol (ICMP)
Briefly explain the Internet protocol (IP)
Internet Protocol (IP) sends the data packets to the correct destination and relies on the Transmission Control Protocol/User Datagram Protocol (TCP/UDP) to deliver them to the corresponding service. IP packets allow communication between two networks. They are routed from the sending network to the receiving network. TCP in particular retransmits any data that is lost or corrupt.
(A Network protocol, also known as an Internet Protocol)
What does TCP/UDP stand for?
Transmission Control Protocol/User Datagram Protocol (TCP/UDP)
Briefly explain the Internet Control Message Protocol (ICMP)
The Internet Control Message Protocol (ICMP) shares error information and status updates of data packets.
This is useful for detecting and troubleshooting network errors. The ICMP reports information about packets that were dropped or that disappeared in transit, issues with network connectivity, and packets redirected to other routers.
Explain the Transport layer of the TCP/IP model
The transport layer is responsible for delivering data between two systems or networks and includes protocols to control the flow of traffic across a network.
What protocols occur in the Transport layer of the TCP/IP model (2)?
- TCP
- UDP
Explain the Transmission Control Protocol (TCP)
The Transmission Control Protocol (TCP) is an internet communication protocol that allows two devices to form a connection and stream data.
It ensures that data is reliably transmitted to the destination service. TCP contains the port number of the intended destination service, which resides in the TCP header of a TCP/IP packet.
What does UDP stand for?
User Datagram Protocol (UDP)
Explain the User Datagram Protocol (UDP)
The User Datagram Protocol (UDP) is a connectionless protocol that does not establish a connection between devices before transmissions.
It is used by applications that are not concerned with the reliability of the transmission. Data sent over UDP is not tracked as extensively as data sent using TCP. Because UDP does not establish network connections, it is used mostly for performance sensitive applications that operate in real time, such as video streaming.
Explain the Application layer of the TCP/IP model
The application layer in the TCP/IP model is similar to the application, presentation, and session layers of the OSI model. The application layer is responsible for making network requests or responding to requests.
This layer defines which internet services and applications any user can access. Protocols in the application layer determine how the data packets will interact with receiving devices.
What are some common protocols that operate in the Application layer of the TCP/IP model (5)?
- Hypertext transfer protocol (HTTP)
- Simple mail transfer protocol (SMTP)
- Secure shell (SSH)
- File transfer protocol (FTP)
- Domain name system (DNS)
What does HTTP stand for?
Hypertext transfer protocol (HTTP)
What does SMTP stand for?
Simple mail transfer protocol (SMTP)
What does SSH stand for?
Secure shell (SSH)
What does FTP stand for?
File transfer protocol (FTP)
What does DNS stand for?
Domain name system (DNS)
What is the OSI model?
A standardized concept that describes the seven layers computers use to communicate and send data over the network.
Network and security professionals often use this model to communicate with each other about potential sources of problems or security threats when they occur.
We will work backwards from layer seven to layer one, going from the processes that involve direct user interaction with the network to those that involve the physical connection to the internet via network components like cables and switches.
What does OSI stand for?
Open Systems Interconnection (OSI)
How many layers does the OSI model have?
Seven (7)
What are the layers of the OSI model?
Layer 7: Application layer
Layer 6: Presentation layer
Layer 5: Session layer
Layer 4: Transport layer
Layer 3: Network layer
Layer 2: Data link layer
Layer 1: Physical layer
What is the seventh (7th) layer of the OSI model?
Layer 7: Application layer
What is the sixth (6th) layer of the OSI model?
Layer 6: Presentation layer
What is the fifth (5th) layer of the OSI model?
Layer 5: Session layer
What is the fourth (4th) layer of the OSI model?
Layer 4: Transport layer
What is the third (3rd) layer of the OSI model?
Layer 3: Network layer
What is the second (2nd) layer of the OSI model?
Layer 2: Data link layer
What is the first (1st) layer of the OSI model?
Layer 1: Physical layer
Define and briefly explain the (7) Application layer of the OSI model
The application layer includes processes that directly involve the everyday user.
This layer includes all of the networking protocols that software applications use to connect a user to the internet. This characteristic is the identifying feature of the application layer—user connection to the internet via applications and requests.
An example of a type of communication that happens at the application layer is using a web browser. The internet browser uses HTTP or HTTPS to send and receive information from the website server. The email application uses simple mail transfer protocol (SMTP) to send and receive email information. Also, web browsers use the domain name system (DNS) protocol to translate website domain names into IP addresses which identify the web server that hosts the information for the website.
Define and briefly explain the (6) Presentation layer of the OSI model
Functions at the presentation layer involve data translation and encryption for the network.
This layer adds to and replaces data with formats that can be understood by applications (layer 7) on both sending and receiving systems. Formats at the user end may be different from those of the receiving system. Processes at the presentation layer require the use of a standardized format.
Some formatting functions that occur at layer 6 include encryption, compression, and confirmation that the character code set can be interpreted on the receiving system. One example of encryption that takes place at this layer is SSL, which encrypts data between web servers and browsers as part of websites with HTTPS.
What formatting functions occur at (6) Presentation Layer of the OSI model?
- Encryption
- Compression
- Confirmation
Define and briefly explain the (5) Session layer of the OSI model
A session describes when a connection is established between two devices.
An open session allows the devices to communicate with each other. Session layer protocols keep the session open while data is being transferred and terminate the session once the transmission is complete.
The session layer is also responsible for activities such as authentication, reconnection, and setting checkpoints during a data transfer.
If a session is interrupted, checkpoints ensure that the transmission picks up at the last session checkpoint when the connection resumes. Sessions include a request and response between applications. Functions in the session layer respond to requests for service from processes in the presentation layer (layer 6) and send requests for services to the transport layer (layer 4).
Define and briefly explain the (4) Transport layer of the OSI model
The transport layer is responsible for delivering data between devices.
This layer also handles the speed of data transfer, flow of the transfer, and breaking data down into smaller segments to make them easier to transport.
Segmentation is the process of dividing up a large data transmission into smaller pieces that can be processed by the receiving system.
These segments need to be reassembled at their destination so they can be processed at the session layer (layer 5). The speed and rate of the transmission also has to match the connection speed of the destination system. TCP and UDP are transport layer protocols.
Define Segmentation
The process of dividing up a large data transmission into smaller pieces that can be processed by the receiving system.
Define and briefly explain the (3) Network layer of the OSI model
The network layer oversees receiving the frames from the data link layer (layer 2) and delivers them to the intended destination.
The intended destination can be found based on the address that resides in the frame of the data packets. Data packets allow communication between two networks. These packets include IP addresses that tell routers where to send them. They are routed from the sending network to the receiving network.
Define and briefly explain the (2) Data link layer of the OSI model
The data link layer organizes sending and receiving data packets within a single network. The data link layer is home to switches on the local network and network interface cards on local devices.
Protocols like network control protocol (NCP), high-level data link control (HDLC), and synchronous data link control protocol (SDLC) are used at the data link layer.
What are some protocols that are used in the (2) Data link layer of the OSI model (3)?
- Network Control Protocol (NCP)
- High-level Data Link Control (HDLC)
- Synchronous Data Link Control (SDLC)
What does NCP stand for?
Network Control Protocol (NCP)
What does HDLC stand for?
High-level Data Link Control (HDLC)
What does SDLC stand for?
Synchronous Data Link Control (SDLC)
Define and briefly explain the (1) Physical layer of the OSI model
As the name suggests, the physical layer corresponds to the physical hardware involved in network transmission.
Hubs, modems, and the cables and wiring that connect them are all considered part of the physical layer.
To travel across an ethernet or coaxial cable, a data packet needs to be translated into a stream of 0s and 1s. The stream of 0s and 1s are sent across the physical wiring and cables, received, and then passed on to higher levels of the OSI model.
What type of information is contained within the header of an IP packet?
- An explanation of how the port number will be processed by the receiving device
- The sender’s IP address, the destination’s MAC address, and the protocol to use
- The message that needs to be transmitted to the receiving device
- A string of data indicating that the data transmission is complete
The sender’s IP address, the destination’s MAC address, and the protocol to use
What characteristics do the TCP/IP and OSI models share? Select all that apply.
- Both models have 7 layers.
- Both models include an application and a transport layer.
- Both models define standards for networking and divide the network communication process into different layers.
- Both models illustrate network processes and protocols for data transmission between two or more systems.
- Both models include an application and a transport layer.
- Both models define standards for networking and divide the network communication process into different layers.
- Both models illustrate network processes and protocols for data transmission between two or more systems.
Both the TCP/IP and OSI models include an application and a transport layer.
Both the TCP/IP and OSI models define standards for networking and divide the network communication process into different layers.
Both the TCP/IP and OSI models illustrate network processes and protocols for data transmission between two or more systems.
What is the Transmission Control Protocol (TCP)?
- An internet communication convention
- A unique address that every device on a network is * assigned
- Guidelines for proper network operations
- A software application that organizes data
An internet communication convention
The TCP is an internet communication convention, or protocol. It allows two devices to form a connection and stream data.
A _____ is a software-based location that organizes the sending and receiving of data between devices on a network.
- segment
- channel
- port
- packet
port
Which layer of the TCP/IP model has protocols that organize file transfers and email services?
- Application layer
- Internet layer
- Network access layer
- Transport layer
Application layer
The application layer has protocols that organize file transfers and email services. It does this by determining how data packets will interact with receiving devices. The application layer is the fourth layer in the TCP/IP model.
