Networking Fundamentals and Configuration

  • Communication is vital and enabled by computer networks.

  • Key network components:

    • Hosts/End-devices: Computers on the network.

    • Servers: Provide data services (e.g., email, web).

    • Clients: Request services from servers.

    • Peer-to-Peer (P2P): Devices act as both client and server.

      • Application includes : file sharing(BitTorrent), multimedia, BitCoin

      • P2P Advantages: easy/less complex, simple tasks

    • P2P Disadvantages: No centralized admin/less security/ scalability

    • Intermediary devices (middleboxes): Connect end-devices; manage data flow.

    • Network media: Carries data (metal wires, fiber optics, wireless).

  • Media types:

    • Metal wires: Electrical impulses.

    • Fiber optics: Light pulses.

    • Wireless: Electromagnetic wave modulation.

  • Network diagrams (topology diagrams) illustrate physical and logical topologies.

  • Network Types:

    • LAN (Local Area Network): Small area, single admin, high speed.

    • WAN (Wide Area Network): Wide area, multiple admins, slower speeds.

  • The Internet: A worldwide collection of interconnected LANs and WANs.

    • No one owns the internet.

    • IETF, ICANN, IAB maintains the internet.

  • Internet Access Technologies:

    • SOHO: Cable, DSL, Cellular, Satellite, Dial-up.

    • Business: Dedicated/Leased Line, Ethernet WAN, DSL, Satellite.

  • Corporate Internet Requirements:

    • High bandwidth, dedicated connections, managed services, converging networks.

  • Reliable Networks Architectures:

    • Fault-tolerance: Limits failure impact; uses packet switching.

    • QoS: Prioritizes voice and video for higher bandwidth and low delay

    • Network Security :confidentiality, integrity and availability.

  • Cloud Computing:

    • Computation and storage over the Internet.

    • Types of services: SaaS, PaaS, IaaS.

    • Cloud Types: Public, Private, Hybrid, Custom.

  • Network Security threats:

    • Viruses, worms, Trojan horses

    • Data interception and theft

    • Internal threats: lost/stolen device, accidental misuse, malicious employees

  • Cisco IOS Access:

    • Shell: User interface (CLI or GUI).

    • Kernel: Hardware/software communication.

    • Access Methods: Console, SSH (secure), Telnet (insecure).

  • IOS Navigation:

    • Command Modes: User EXEC (>), Privileged EXEC (#), Configuration Modes.

    • Use enable, configure terminal, line commands to navigate modes.

  • IOS Command Structure:

    • Basic structure Keyword + Argument

    • Syntax is important and specific

  • Basic Device Configuration:

    • Set hostname (no spaces, < 64 characters).

    • Secure EXEC mode (enable secret password).

    • Configure console/VTY passwords (line console 0, line vty 0 15, login).

    • Encrypt passwords (service password-encryption).

    • Set banner message (banner motd #message#).

  • Save Configurations:

    • running-config (RAM) and startup-config (NVRAM); use copy running-config startup-config.

    • Use reload command to restore to previous configurations

  • Ports and Addresses:

    • IPv4 (dotted decimal), IPv6 (hexadecimal with colons).

    • Subnet mask differentiates network/host portions.

    • Default gateway for remote network access.

  • Configure IP Addressing:

    • Manual or DHCP for end devices in both IPv4 and IPv6.

    • SVI (Switch Virtual Interface) for remote switch access.