Computer Networks Overview

Networks Affect Our Lives

• Networks are important for communication and connect people both locally and globally.

Network Components

• A host or end device refers to any computer connected to a network.
• Wireless Internet Service Providers (WISPs) connect subscribers to specific access points or hotspots primarily found in rural areas.
• Wireless broadband is a common solution for home and small businesses using cellular technology and external antennas.

Network Representations and Topologies

• Network diagrams visually represent network connections, outlining various components and their relationships.
• Network topologies describe the physical or logical arrangement of network devices.
• Common network topologies include:
  • Bus Topology
  • Star Topology
  • Ring Topology
  • Mesh Topology

Common Types of Networks

• Networks are categorized based on the geographical area coverage, number of users, services provided, and responsibility.
• Local Area Networks (LANs) connect devices in a limited geographical area.
  • LANs are typically administered by a single entity.
  • LANs provide high-speed bandwidth for internal devices.
• Wide Area Networks (WANs) connect LANs over broader geographical regions.
  • WANs are usually managed by one or more service providers.
  • WANs generally offer slower speeds compared to LANs.
• The internet comprises a global collection of interconnected LANs and WANs.
  • LANs connect to each other through WANs.
  • The internet is not controlled by any specific individual or group.

Internet Connections

• Internet Service Providers (ISPs) provide access to the internet.
• Common internet connection types include:
  • Dialup
  • DSL
  • Cable Modem
  • Satellite
  • Fiber-optic
  • Wireless

Reliable Networks

• Reliable networks possess four fundamental requirements:
  • Availability: Ensuring network accessibility for users.
  • Reliability: Maintaining network functionality and data integrity.
  • Scalability: Adapting to changes in network size and demand.
  • Security: Safeguarding the network and its data from threats.

Network Trends

• Bring Your Own Device (BYOD) allows users to access information and communicate using their personal devices such as laptops, tablets, and smartphones.
• Online collaboration tools enable users to work together on projects remotely.
  • Collaboration tools like Cisco WebEx facilitate instant communication and interaction.
• Video communication allows for visual communication with anyone regardless of location.
  • Video calls are becoming increasingly important for effective collaboration.
• Cloud computing enables storing and retrieving data remotely on internet-based servers.
  • Applications can also be accessed via the cloud.
  • Cloud computing offers flexibility and accessibility to devices anywhere.
• Four types of cloud services exist:
  • Public cloud: accessible to the general public through a pay-per-use model.
  • Private cloud: exclusive to a specific organization or entity.
  • Hybrid cloud: combines both public and private cloud components.
  • Community cloud: shared by a group of organizations with similar requirements.

Network Security

• Network security is essential for protecting data and resources from various threats.
• Security threats can be external or internal.
  • External threats originate from external sources and include:
    • Viruses, worms, and Trojan horses
    • Spyware and adware
    • Zero-day attacks
    • Threat Actor attacks
    • Denial of service attacks
    • Data interception and theft
    • Identity theft
  • Internal threats originate within the network and include:
    • Lost or stolen devices
    • Accidental misuse by employees
    • Malicious employees
• Security solutions are crucial for mitigating threats.
  • Security solutions for home or small office networks typically include:
    • Antivirus and antispyware software
    • Firewall filtering
  • Larger networks may also employ:
    • Dedicated firewall system
    • Access control lists (ACLs)
    • Intrusion prevention systems (IPS)
    • Virtual private networks (VPNs)

The IT Professional

• Cisco Certified Network Associate (CCNA) certification demonstrates knowledge of fundamental networking technologies.
  • CCNA validates skills for adopting next-generation network technologies.
  • The new CCNA focus emphasizes:
    • IP foundation and security
    • Wireless, virtualization, automation, and network programmability
• DevNet certifications validate software development skills at associate, specialist, and professional levels.
• Specialist certifications demonstrate proficiency in job-specific roles and areas of interest.