network architectures

• A network is a group of devices connected together (at least 2)
• Wifi is a technology that allows devices to exchange data WIRELESSLY over LAN (Local Area Network). It is used in homes, businesses...
• Router is a networking device that connects different networks together and directs data traffic between them, often serving as a central switch/hub for connecting devices.

  Forwards data between IP addresses
• Switch is a networking device that shares data to all connected devices over cable intelligently, improving network efficiency and reducing collisions.
• Hub is a networking device that works like a switch but not intelligent, as a hub does not manage the data that flows through it, it simply distributes it to everyone. switches are more secure than hubs.
• Bridge is a networking device that connects 2 separate networks.
• A server is a large powerful computer that provides services, resources and data to other computers (known as clients). They have various roles such as web servers, file servers, database servers, etc.
• The internet is a global network connected using IP (INTERNET PROTOCOL). It facilitates communication, information sharing, and access to resources on a global scale such as World Wide Web, email, chat, gaming...
• Benefits of internet include:

  • Allows a business to reach unlimited markets
  • Low-cost marketing
  • Ease of transactions
  • Access to information
  • Internal & external communication
• Drawbacks of internet include:

  • Risk of data thefs
  • Impersonalization
  • High competition
• An Intranet is a private network with access restricted to users within an organization. It uses internet technologies to provide internal services such as internal websites, file sharing, communication tools, etc.
• Benefits of an Intranet includes:

  • Improves internal collaboration & communication
  • Involves only specific users
  • Enhances employee productivity in an organization
  • More secure
• Drawbacks of an intranet includes:

  • Complexity to mantain
  • Costly implementation
  • There are still security threats
• An extranet is a controlled private network with access to the internal organization AND also shares selected information/resources to external entities, such as partners, suppliers and customers. It can be used when you want to improve collaborations with partners, communication with customers...
• Benefits of extranet include:

  • High security of data due to advanced security measures
  • Increased customers satisfaction in a business as the business is accessible 24/7 to the customers.
• Drawbacks of extranet includes:

  • Implementation and mantainance costs such as hardware, software, staff training, and repair costs if needed)
  • May still have security issues
• A VPN is a technology that allows users to securely access a private network over a public network such as the internet. It creates a secure and encrypted connection between a device and a remote server over the internet.
• Technology required for VPNS

  • A tunneling protocol, allows public channels like HTTP to carry encrypted data. It involves creating a virtual pipe between two devices.
  • An encrypted protocol. This ensures that the data cannot be read by third parties.
  • Authentication. This can be done using a username and password, etc.
  • The VPN client: software that is installed on the user's device. Establishes encrypted connection to the remote server.
  • The VPN server: remote server that receives the encrypted traffic from the VPN client and decrypts it. encrypts the traffic sent back to client.
• Advantages of VPN

  1. Resources such as files, printers and databases can be shared over remote hosts (distant devices) without requiring exclusive connections
  2. Using leased lines can be expensive, whereas fully featured VPN softwares are freely available as an open source
  3. VPN encrypt your internet traffic, making it difficult for third parties to intercept with your data (enhances security and privacy)
  4. Allows users to connect to servers in different locations that certain content may be restricted in.
• Disadvantages of VPN

  1. The encryption and routing processes can lead to reduction in internet speed
  2. Setting up VPN's can be challenging, especially for non-technical users
  3. Security of VPN'S depends on the trustworthiness of VPN service providers, so if you choose a less reputable server, they may log into your data
• There are many different types of networks:

  • Local Area Network (LAN)
  • Wireless Local Area Network (WLAN)
  • Wide Area Network (WAN)
  • Storage Area Network (SAN)
• The Open Systems Interconnection (OSI) Seven Layer Model is a theoretical model that describes how data is transmitted between devices. The seven layers are: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

  • Each layer is an abstraction 
  • Allows software and hardware at each layer to concentrate on one thing. Without worrying about other layers. 
• On the internet, some layers are grouped. (TCP/IP)

  1. Application: Program that sends out the data (apps: whatsapp, tiktok…) (HTML/SMTP). 
  2. Transport: Data is broken into packets (TCP), 
  3. Network: Packets are addressed with destination and sender’s address. (IP). EX: ROUTER.
  4. Data link: Packets are converted into binary and sent. EX: SWITCHES.
  5. Physical: Transmits data over physical medium. EX: HUBS, REPEATERS.