Module 1: Networking Today - Page-by-Page Notes

This module introduces foundational networking concepts, explaining how networks affect daily life, detailing network components, representations, and common types. It also covers internet connections, requirements for reliable networks, emerging network trends, network security, and IT professional opportunities.

Network Components

End devices are where messages originate or are received. Every computer on a network is a host or end device. Servers provide information (e.g., email, web, file servers) to clients, which request information from servers.

In a Peer-to-Peer Network, a device can be both a client and a server. These are easy to set up, less complex, and lower cost but lack centralized administration, are less secure, and not scalable. Typical tasks include simple file transfers and printer sharing, though performance can be slower.

Intermediary network devices (e.g., switches, routers, firewalls) interconnect end devices, regenerating signals, maintaining pathway information, and notifying of errors. Network media facilitates transmission using metal wires (electrical impulses), fiber-optic cable (light pulses), or wireless transmission (electromagnetic waves).

Network Representations and Topologies

Network diagrams (topology diagrams) use symbols for devices. Key terms include Network Interface Card (NIC), physical port, and interface. Physical topology diagrams show device locations and cable installation, while logical topology diagrams illustrate devices, ports, and addressing schemes.

Common Types of Networks

Network infrastructures vary by size, users, services, and responsibility. The two most common types are Local Area Network (LAN) and Wide Area Network (WAN).

  • LANs span small geographical areas, typically administered by a single organization/individual, and provide high-speed bandwidth internally.

  • WANs span wide geographical areas, interconnect LANs over long distances, are administered by one or more service providers, and typically offer slower speeds between LANs.

The Internet is a worldwide collection of interconnected LANs and WANs, not owned by any single entity, and governed by organizations like IETF, ICANN, and IAB.

An Intranet is a private collection of LANs and WANs internal to an organization, accessible to authorized members. An Extranet provides secure access to an organization’s network for external partners.

Internet Connections

Home and small office connections include Cable, DSL, Cellular, Satellite, and Dial-up. Businesses may require higher bandwidth and dedicated connections, utilizing Dedicated Leased Lines, Ethernet WAN, Business DSL, or Satellite.

A converged data network carries multiple services (data, voice, video) over a single link, using the same infrastructure, rules, and standards.

Reliable Networks: Network Architecture

Network architecture refers to technologies supporting data movement. Four essential characteristics for meeting user expectations are:

  1. Fault Tolerance: Limiting failure impact through redundancy (multiple paths). Packet-switched networks are more flexible than circuit-switched networks.

  2. Scalability: Expanding easily to support new users and applications without impacting existing services, achieved by following accepted standards.

  3. Quality of Service (QoS): Ensuring reliable delivery, especially for voice and live video, by managing traffic flow.

  4. Security: Protecting infrastructure and information. Goals are Confidentiality (only intended recipients read data), Integrity (data unaltered), and Availability (timely access).

Network Trends

Networks continually evolve with technologies like Bring Your Own Device (BYOD), online collaboration, video communications, and cloud computing.

Network Security Threats and Solutions

Security is vital. Threat vectors can be external (Viruses, worms, Trojan horses, Spyware and adware, Zero-day attacks, Threat Actor attacks, Denial of Service (DoS) attacks, Data interception and theft, Identity theft) or internal (Lost or stolen devices, Accidental misuse by employees, Malicious employees).

Security must be layered. Home/small office solutions include antivirus/antispyware and firewall filtering. Larger networks require dedicated firewall systems, Access Control Lists (ACL), Intrusion Prevention Systems (IPS), and Virtual Private Networks (VPN).

The IT Professional: CCNA

Cisco Certified Network Associate (CCNA) certification demonstrates foundational networking knowledge, including IP foundation, security, wireless, virtualization, and automation. DevNet certifications validate