Module 1

Network Models

  • Topology Definition: Defines how parts of a network collaborate.

  • Physical Topology:

    • Refers to hardware layout (computers, devices, cables).

  • Logical Topology:

    • Software management of resource access (controlled by Network Operating System - NOS).

    • Essential in client-server models.

Peer-to-Peer Network Model (P2P)

  • Definition: Each computer's OS controls its resources without centralized control.

  • Key Features:

    • Computers are termed nodes or hosts.

    • Each computer manages its administration and security.

  • Advantages:

    • Simple configuration.

    • Cost-effective for small setups.

  • Disadvantages:

    • Scalability issues.

    • Potential security vulnerabilities.

    • Not suited for large installations.

  • Authority: No computer has superiority; all communicate directly.

Client-Server Network Model

Overview

  • Definition: Resources managed by a NOS via a centralized directory (Active Directory - AD).

  • Key Functions of NOS:

    • Central management of user data, access, and resources.

    • Users can access network resources from any computer.

Key Concepts

  • Windows Domain: A grouping of computers controlled by a Windows Server.

  • Client Definition: A computer making requests for resources from a server.

Requirements for Servers

  • Hardware Needs: More memory, processing power, specialized hardware for network management.

  • Role of NOS: Manages user access, file control, communication rules, and supplies applications/data to clients.

Client-Server Applications

  • Definition: Network services offered comprise applications and data resources.

  • Client-Server Dynamics: Clients request data or services from servers.

  • Example: A web browser (client) requests a page from a web server (server).

Network Protocols and Services

Important Protocols

  • Primary Protocols:

    • TCP (Transmission Control Protocol)

    • IP (Internet Protocol)

  • Client-Server Applications Include:

    • Web services, Email, DNS, FTP, Database, Remote access.

Email Protocols

  • Sending Emails: Utilizes SMTP (Simple Mail Transfer Protocol).

  • Receiving Emails: POP3 or IMAP4 implementations on the client end.

Network Hardware Overview

  • **Overview of LAN:

    • Definition: Local Area Network is typically confined to a single location.

  • Switch Functionality:

    • Directs incoming data to the correct ports ensuring delivery to intended devices.

  • Common Topology: Star topology – all devices connect to a central switch.

  • Network Interface Card (NIC): Device for connecting to the network, also known as network adapter.

LAN Hardware Types

  1. Router:

    • Connects and manages traffic between different networks.

    • Can serve home networks (SOHO) or industrial systems.

  2. Switch:

    • Operates within just its own local network, directing traffic.

Types of Networks

  • WAN (Wide Area Network): Connects multiple LANs over geographically dispersed areas.

  • MAN (Metropolitan Area Network): Group of LANs within a specific geographical area.

  • PAN (Personal Area Network): Very local network connecting personal devices.

OSI Model Overview

Importance

  • Describes how applications on different computers communicate through layers.

Layers Breakdown

  • Layer 7: Application Layer: Facilitates user services and system utilities (e.g., SNMP).

  • Layer 6: Presentation Layer: Handles data formatting, encryption, and compression.

  • Layer 5: Session Layer: Synchronizes application data exchange, can recover lost messages.

  • Layer 4: Transport Layer: Manages payload transport, ensuring reliable delivery via TCP or UDP.

  • Layer 3: Network Layer: Directs packets across networks using IP for routing.

  • Layer 2: Data Link Layer: Interfaces with hardware, creating frames for transmission.

  • Layer 1: Physical Layer: Concerns physical transmission of signals across mediums.

Protocol Data Unit (PDU)

  • Definition: Represents a group of bits transitioning through network layers, referred to simply as messages.

OSI Layer Interactions

  • Illustrates how various OSI layers function together during communication (e.g., web requests).

Safety Protocols and Best Practices

Emergency Procedures

  • Key Elements:

    • Awareness of escape routes, fire suppression systems, emergency switches, and security protocols.

Personal Safety Procedures

  • Electrical Safety: Follow OSHA guidelines when operating tools, wear PPE, keep tools in order.

  • Heavy Object Handling: Use correct lifting techniques to prevent injury.

  • Static Electricity Precautions: Protect sensitive components from ESD by grounding yourself.

Troubleshooting Network Problems

Seven-Step Model

  1. Identify the problem and its symptoms.

  2. Establish probable cause theory.

  3. Test theory for determining cause.

  4. Develop a resolution plan.

  5. Implement solution or escalate.

  6. Verify functionality and apply preventive measures.

  7. Document findings and outcomes.

Summary

  • After completing the module:

  • Ability to distinguish between network types, identify applications/protocols, describe network hardware, articulate OSI model layers, apply safety best practices, and implement troubleshooting methods.