1. Network Design

Network design refers to the architecture and structure of a network. It includes the selection of network topology, hardware, and software to ensure smooth operations.

Key Components of Network Design

• Network Topology – Defines how devices are arranged (e.g., star, bus, mesh, hybrid).
• Bandwidth Planning – Determines the required data transfer rate for smooth operation.
• Scalability – Ensures that the network can expand in the future without performance issues.
• Redundancy & Failover – Adds backup systems to avoid downtime in case of failures.
• Load Balancing – Distributes network traffic to optimize performance and prevent overload.
• Cloud Integration – Supports hybrid or fully cloud-based networks (AWS, Azure, GCP).

Network Design Models

Hierarchical Model: Core, Distribution, Access layers.

Flat Network Design: Fewer layers, used in small businesses.

Software-Defined Networking (SDN): Uses centralized control and automation.

2. Network Planning

Network planning ensures that resources are effectively allocated before deployment.

Steps in Network Planning

• Assess Requirements – Identify business needs, users, and applications.
• Capacity Planning – Estimate future demand and scalability needs.
• Hardware & Software Selection – Choose routers, switches, firewalls, and software.
• IP Address Management – Assign and segment IP addresses (IPv4, IPv6).
• Security Measures – Integrate firewalls, encryption, VPNs, and intrusion detection systems.
• Redundancy Planning – Ensure backup power (UPS), secondary ISPs, and failover systems.

Network Planning Tools

• Cisco Packet Tracer
• SolarWinds Network Performance Monitor
• PRTG Network Monitor
• Wireshark (for packet analysis)

3. Network Development

Network development involves implementation, testing, and optimization of the network infrastructure.

Key Stages in Network Development

• Procurement & Deployment – Installing hardware (routers, switches, firewalls).
• Configuration & Setup – Assigning IPs, VLANs, access controls, and firewall rules.
• Network Testing – Checking speed, latency, and connectivity.
• Performance Optimization – Tweaking QoS (Quality of Service) settings, reducing bottlenecks.
• Monitoring & Troubleshooting – Using tools to detect and resolve issues.

Protocols Used in Network Development

• TCP/IP – Core communication protocol.
• DNS, DHCP – Name resolution and automatic IP assignment.
• BGP, OSPF, EIGRP – Routing protocols for traffic control.
• 802.1X, WPA2, WPA3 – Authentication and encryption for security.

4. Network Security

Network security protects infrastructure from cyber threats, unauthorized access, and attacks.

Network Security Measures

• Firewalls – Block unauthorized access (e.g., Cisco ASA, pfSense).
• Intrusion Detection/Prevention Systems (IDS/IPS) – Detect and mitigate threats.
• Virtual Private Networks (VPNs) – Secure remote access using encryption.
• Access Control Lists (ACLs) – Restrict access based on rules.
• Network Segmentation – Divide networks to limit attack spread.
• Multi-Factor Authentication (MFA) – Strengthen login security.
• Zero Trust Security Model – Verify every device and user.

Common Network Threats

• DDoS Attacks – Overloading servers with traffic.
• Man-in-the-Middle Attacks – Intercepting data between users.
• Phishing & Social Engineering – Tricking users into revealing credentials.
• Ransomware – Encrypting files and demanding payment.
• SQL Injection – Exploiting databases via web vulnerabilities.

Security Tools

• Snort, Suricata – IDS/IPS solutions.
• Wireshark – Network traffic analyzer.
• Nmap – Network scanning and mapping.
• Metasploit – Penetration testing framework.