Topic 3 - Networks

• Server

  a computer system or a software application that provides a service to other computer systems on the same network
• Client

  a computer system or software application that requests a service from a server connected to the same network
• Hub


  connector that connects the wires coming from different sides and operates only on physical layers of the OSI model
• Switch

  point to point communication device that operates at the data link layer of the OSI model
• How does switch find the correct destination?

  It uses a switching table to find the correct destination
• Router

  contains routing table that enables it to make decisions about the route to determine the paths between the source and destination that is the best for a particular transmission
• What are the similarities of LAN & WLAN?

  • both act on a local level
  • both allow communication
  • both used to connect devices
  • both allow sharing of resources
• What are the differences of LAN & WLAN?

  • They use a different transmission medium
  • LAN is faster
  • LAN is safer
  • WLANs have more flexibility
• Is LAN OR WLAN faster?


  LAN
• Does LAN or WLAN have more flexibility?

  WLAN
• What are the similarities of LAN & VLAN?

  • both act on local level
  • both have same attributes
  • both allow communication
  • both used to connect devices
  • both allow sharing of resources
• What are the differences of LAN & VLAN?

  • VLAN has better performance
  • VLAN is safer
  • VLAN is more flexible
  • VLAN is independent of the medium and virtual topology of the network
  • VLAN can allow for easy partition of resources
• Benefit of LAN over VLAN?

  Management of LAN is easier than VLAN
• Types of networks include LAN, WAN, VLAN, SAN, WLAN, Internet, Extranet, VPN, PAN, and P2P
• Computer Network

  Group of computer systems and hardware devices linked through communication channels for communication and resource-sharing
• LAN


  Local Area Network covering a local area, commonly found in offices, buildings, and homes using Ethernet.
• WAN

  Wide Area Network, covering larger areas, such as multiple buildings or countries, with the internet being the most popular example.
• VLAN

  Virtual Local Area Network, a logical group of devices appearing on the same LAN despite geographical distribution for scalability, security, and ease of management.
• SAN

  Storage Area Network, secure high-speed data transfer network providing access to consolidated block-level storage, accessible to multiple servers.
• WLAN

  Wireless Local Area Network, wireless distribution method for devices using high-frequency radio waves, often including an access point for internet access, commonly known as Wi-Fi.
• INTERNET


  Globally connected network system using TCP/IP protocols for data transmission, consisting of global exchanges connected by various technologies.
• EXTRANET

  Controlled private network allowing access to specific information without granting access to the entire network, often restricted through user IDs, passwords, and authentication mechanisms.
• VPN


  Virtual Private Network, using the internet to allow remote access to a network while encrypting the connection, commonly used for remote work and privacy.
• PAN

  Personal Area Network covering a very small area, usually a room, with Bluetooth being a popular wireless PAN technology and USB being a common wired PAN.
• PEER-TO-PEER


  Network model where computers or hardware devices exchange files directly among each other, resembling an "equal client" system without a central server.
• Importance of Standards in Networking

  • Standards are crucial in networking.
  • They provide a common ground for manufacturers to build their systems.
  • Interconnecting products from different vendors would be challenging without standards.
  • Communication would be difficult or impossible without agreed-upon standards.
• Layers of the OSI Model

  • Application
  • Presentation
  • Session
  • Transport
  • Network
  • Data Link
  • Physical Layer
• Application(HTTP, SNMP, FTP)


  Interface for end point service. Ex: Web browsing & email
• Presentation(WMV, JPEG, PNG)

  Formats application data for delivery. Ex: compression & encryption
• Session(Connection management)


  manages sessions between application process
• Transport (TCP, UDP)


  Host to host communications
• Network (IP)

  Source & destination ip addresses
• Data Link (MAC, FCS)


  Source and destination MAC addresses
• Physical

  data encoding
• VPN Technologies

  1. Hardware & software requirements
  2. Secure VPN
  3. Trusted VPN
  4. Hybrid VPN
• VPN hardware/software requirements

  1. Internet access
  2. VPN Software
  3. VPN Routers
  4. VPN Appliances
  5. VPN Concentrators
  6. VPN Servers
• Secure VPN

  1. Internet protocol security (IPSec)
  2. Secure sockets Layer (SSL)
• Trusted VPN


  Technologies for layer 2 VPNS

  • Asynchronous Transfer mode circuits
  • Frame relay circuits
  • Transport of layer 2 frames over MPLS
• Hybrid VPN

  combination of both secure and trusted technologies or a combination of 2 VPN technologies
• VPN Types

  1. site to site VPN
  2. remote access VPN