Network Planning Methodologies and Requirements Analysis

Posted on Sep 28, 2025 in Business Administration and Innovation Management

Fundamentals of Network Planning and System Approaches

Why Network Planning is Crucial

A network is not just cables and routers; it is the foundation of business operations. Without proper planning, organizations risk downtime, bottlenecks, security gaps, and wasted money.

  • Example: An airline reservation system that crashes during the holiday season can result in millions lost.

Planning ensures the network meets current needs (like today’s users and applications) while also being scalable for the future.

Levels of Network Planning

Network planning is typically categorized into three distinct levels:

  • Strategic Planning: Focuses on long-term goals, usually set at the executive level.
    • Example: A bank deciding to migrate all infrastructure to the cloud within five years.
    • Key Idea: Broad, visionary, but not technical.
  • Tactical Planning: Medium-term planning that bridges strategy and operations.
    • Example: A company running a six-month pilot SaaS deployment before full migration.
    • Key Idea: Actionable steps that prove or support the overall strategy.
  • Operational Planning: Short-term, day-to-day configurations and maintenance.
    • Example: Adding new VLANs for a department or reconfiguring routers for remote users.
    • Key Idea: Detailed, technical tasks.

Contrast: Strategic = “where we want to go,” Tactical = “projects to get there,” Operational = “hands-on tasks to make it work.”

Network Planning Methodologies

The Waterfall Model

This model uses sequential stages:

  1. Requirements
  2. Logical Design
  3. Physical Design
  4. Implementation
  5. Testing
  6. Operations

It works best when requirements are stable and clear at the start (e.g., government contracts where specifications are fixed). Weakness: It is inflexible and does not adapt well to changes mid-project.

Top-Down Methodology

This approach starts from business needs, translates them into technical requirements, and then designs the logical and physical architecture.

  • Advantage: Ensures the network supports strategic goals, rather than just following technology trends.
  • Example: Amazon designing global network capacity around its business growth forecast.
  • Weakness: Requires more expertise and time investment.

Service-Based Networking

This methodology focuses on the quality and type of services offered rather than the underlying devices.

  • Example: Guaranteeing a VoIP service will always get <100 ms delay, while email traffic receives best-effort service.
  • Advantage: Directly links user experience and Quality of Service (QoS) to network design.

Comparison Summary:

  • Waterfall: Structured but rigid.
  • Top-Down: Flexible and business-aligned.
  • Service-Based: User-service focused, excellent for QoS-based networks.

The Systems Approach

The systems approach views the network as a complex, interconnected whole:

  • Decomposition: Breaking the network into manageable subsystems (e.g., LAN, WAN, Data Center).
  • Holism: Understanding that subsystems interact (a bottleneck in the WAN affects LAN performance).
  • Emergent Behavior: The whole network may behave differently than the sum of its individual parts.
  • Example: Ten well-performing LANs connected may still overload a single WAN link.

Key Concept: “Emergent behavior” means system-wide effects that are not visible when components are isolated.

Requirements Analysis for Network Design

Purpose of Requirements Analysis

Requirements analysis ensures the network design is aligned with business needs while respecting technical limitations. Without this crucial step, networks may be “overbuilt” (too expensive) or “underbuilt” (too weak to handle demand).

Business Goals and Constraints

Business Goals

These define what the organization wants to achieve:

  • Example: A university wants comprehensive Wi-Fi access across the entire campus for students and staff.
  • Example: A financial institution requires high security and zero downtime for trading systems.

Constraints

These are the limitations that must be respected during the design process:

  • Budget: Capital Expenditure (CapEx) and Operational Expenditure (OpEx).
  • Time Frame: Project deadlines and implementation schedules.
  • Skilled Manpower: Availability of in-house staff versus outsourcing needs.
  • Regulations: Compliance requirements (e.g., GDPR, HIPAA, PCI-DSS).

Contrast: Goals = what you WANT; Constraints = what you MUST respect.

Categorizing Network Requirements

User Requirements

Relate directly to what end-users need for productivity and usability.

  • Example: Hospital staff need low-latency access to patient records and medical imaging systems.

Application Requirements

Focus on the traffic characteristics and performance needs of specific applications:

  • Mission-Critical: Requires maximum uptime (e.g., airline booking, ATM transactions).
  • Rate-Critical: Requires high bandwidth (e.g., video streaming, large data transfers).
  • Real-Time: Requires low latency and jitter (e.g., VoIP, video conferencing, gaming).

Device Requirements

Depend on the hardware specifications of network components and endpoints (CPU, memory, storage, firmware).

  • Example: Video streaming servers require high throughput Network Interface Cards (NICs).

Network Requirements

Pertain to the overall network architecture and infrastructure capabilities (scalability, performance, addressing, routing, interoperability).

  • Example: An ISP must design a scalable IPv6 addressing scheme to accommodate future growth.

Note: Application requirements focus on traffic needs; User requirements focus on usability and experience.

Requirement Prioritization (RFC 2119/8174)

Requirements are prioritized using standardized terminology:

  • Required (MUST): Non-negotiable features essential for system function.
  • Recommended (SHOULD): Highly desirable features that improve performance or usability.
  • Optional (MAY): Features that are nice to have but not critical.

Example for a Hospital Network:

  • Required: Patient database uptime of 99.99%.
  • Recommended: Telemedicine integration capabilities.
  • Optional: Guest Wi-Fi access for visitors.

Essential Design Trade-offs

Network design often involves balancing competing factors:

  • Security vs. Performance: Heavy encryption and firewalls can slow traffic.
  • Reliability vs. Cost: Redundancy (e.g., dual links, backup devices) is expensive.
  • Flexibility vs. Complexity: More flexible systems are often harder to manage and maintain.