Network Implementation
Learning Objectives
Understand the use of port numbers
Describe common network services
Explain the advantages and disadvantages of a specific network service
Recognise resources shared in a network
Setup simple Ethernet and wireless networks
Recognise factors of consideration when setting up a simple home network
Application and Career
Network Engineer Role
Network engineers serve as the architects and caretakers of complex networking systems.
Responsibilities include designing, implementing, and maintaining infrastructure for data transfer and communication.
Necessary skills involve a deep understanding of networking technologies, protocols, and devices.
Operate across multiple industries: telecommunications, finance, healthcare, education, government, etc.
Collaborate with IT professionals: system administrators, security analysts, software developers.
Growing demand for skilled network engineers due to reliance on digital information and services.
Network Service and Network Implementation
Introduction
Building on knowledge from Core C - Internet and its Applications.
Explores the relationship between network addresses and port numbers, common network services, and simple network setups.
6.1 Network Address and Port Number
Introduction to Port Number
Unique IP addresses are required for device communication in a network.
Port numbers are numerical identifiers for different services/applications on the same network address.
Defined by the Transport Control Protocol (TCP) and must be an unsigned 16-bit number (0 to 65535).
Each running application is assigned a specific port number to direct incoming data appropriately.
Example of Port Numbers
Port assignments for various applications:
Port 20/21: File Transfer Protocol (FTP)
Port 443: HTTPS
Port 25: SMTP
Port 80: HTTP
Port 3306: MySQL
Reserved Port Numbers
Ports 0 to 1023 are reserved as system ports for widely used network services.
TCP allows unassigned ports (0 to 65535) for applications too.
Ports and Network Address Notation
Port Number is specified postfixed to the IP address with a colon, for example: 192.168.0.10:443.
Applications communicate over specified ports, where services can be hosted concurrently at the same network address.
Factors for Non-default Port Usage
Port Conflict: Using another port when the default is occupied.
Security: Obscuring the service to hinder unauthorized access.
Multiple Instances: Running multiple instances of the same service under one domain (e.g., development testing).
Firewall Restrictions: Hosting on different ports due to strict firewall rules.
6.2 Network Services
Overview of Network Services
Enable seamless user interaction through various network services when browsing and sharing content.
Common Network Services
A. Web Server
Delivers web content (web pages, images, videos) via HTTP requests.
Executes server-side scripts (like PHP) for dynamic content generation.
Major software: NGINX and Apache.
B. Database Server
Manages multiple databases and implements user authentication and access control mechanisms.
Server-side scripts execute queries to update/retrieve data from databases.
C. File Server
Centralizes file access across the network with a directory-based structure for file management.
Implements user authentication and access control to protect shared files.
Permissions for Files: Read, Write, and Execute.
Permissions for Folders: Listing files, creating new files, deleting or renaming existing files.
D. DHCP Server
Dynamically assigns unique IP addresses to devices in a network, managing a predefined scope of IPs.
IP leases have fixed durations and can reclaim IPs from inactive devices.
E. Domain Controller
Implements user login authentication and controls network resource access.
Centralizes management of user accounts and rights, enforcing security policies.
F. Proxy Server
Acts as an intermediary for requests between users and the Internet, providing caching and filtering.
Advantages: Anonymity, improved performance due to caching.
Disadvantages: Potential latency, security risks if not secured.
6.3 Sharing Resources Within Network
Resource Sharing
Resources can include hardware (e.g., printers) and services.
Sharing Hardware: Printers
Network Printer: Directly connects to a network; accessible by all users on the network.
Print Server: Manages multiple network printers, enabling centralized print job handling.
Sharing of Files
Implement access control and user authentication for secured access to shared folders.
Ensure regular backups to prevent data loss and maintain data integrity.
Sharing of Internet Connections
One Internet subscription can be shared across multiple devices in the network, reducing costs.
6.4 Basic Network Implementation
Setting Up a Simple Home Network
Demonstrates key components: routers, switches, modems, and network printers.
Ethernet cables (CAT 5/6) are used for wired connections; wireless connections utilize WiFi.
Connecting to ISP
Most home networks use PPPOE for connecting to ISPs, requiring username/password authentication for IP address assignment.
IP Address Assignment
DHCP automatically assigns unique IP addresses to devices; static IPs can be configured separately for critical devices such as printers.
Summary of Ethernet and Wireless Standards
Ethernet categories (5, 5e, 6) define throughput and connection lengths for wired connections.
WiFi standards (Wi-Fi 6/5) dictate wireless connection speed and coverage, requiring strategic router placement and configuration for optimal performance.
Chapter Summary
Port Number and Network Addresses
Port Numbers identify services on a network; non-default ports can help in specific circumstances (conflicts, security).
Network Services Overview
Compare file servers, DHCP servers, domain controllers, and proxy servers in terms of functionality, advantages, and drawbacks.
Chapter Exercises
Include a variety of questions to reinforce understanding of topics like DHCP server functionality, advantages of cloud storage versus file servers, and specifics of network service roles.