Reasoning and Technical Planning

Introduction

This post is based on conversation with ChatGPT exploring elements of Reasoning and Argument, and how they relate to Technical Planning, with focus on network engineer.

Foundations of Reasoning and Technical Planning

A practical guide for network engineers

Part 1 — Reasoning: The Structure Beneath Engineering Decisions

Network engineering is not just configuration work.
It is applied reasoning under constraints.

Understanding how reasoning is structured gives you better judgment, clearer communication, and more defensible designs.

1. Clause — The Atomic Unit of Technical Thought

A clause is the smallest unit of language that expresses a relationship (usually cause, condition, or effect).

Examples:

  • The switch is end-of-life.
  • Because the switch is end-of-life, it lacks vendor support.
  • If we replace the switch, downtime will occur.

Why clauses matter to engineers

  • Engineering thinking is largely cause-and-effect.
  • Cause-and-effect is expressed through clauses.
  • Vague clauses lead to vague thinking, which leads to bad design decisions.

Practical examples:

  • If the uplink is 1G, then aggregation capacity is limited.
  • Because PoE budget is insufficient, cameras may fail under load.

Clear clauses produce clear mental models.

2. Argument — Engineering Justification

An argument is a structured set of statements that supports a conclusion.

Example:

  • Premise: The current HPE switches are end-of-life.
  • Premise: End-of-life switches do not receive security updates or vendor support.
  • Conclusion: Therefore, the switches should be replaced.

Why arguments matter

  • Every design choice must be justified.
  • Managers, auditors, and stakeholders ask why, not how.
  • Arguments turn experience into defensible decisions.

An undocumented design is just an opinion.
An argument is engineering.

3. Syllogism — The Formal Shape of Technical Reasoning

A syllogism is a formal argument with a predictable structure:

  1. Major premise (general rule)
  2. Minor premise (specific case)
  3. Conclusion (logical result)

Example:

  • All unsupported network equipment increases operational risk.
  • These switches are unsupported.
  • Therefore, these switches increase operational risk.

Why syllogisms matter

  • They expose hidden assumptions.
  • They allow you to test whether reasoning is valid.
  • They prevent gut-feel decisions from dominating design.

Most technical planning relies on many implicit syllogisms.

4. Logical Flow of Argument — Making Reasoning Followable

Logical flow is the order in which ideas are presented so others can follow your reasoning.

Good logical flow

  1. State the problem
  2. Explain why it matters
  3. Define constraints
  4. Evaluate options
  5. Recommend a solution

Poor logical flow

  • Jumping straight to a product recommendation
  • Explaining implementation before justification
  • Mixing risks, requirements, and solutions randomly

Logical flow builds trust and reduces resistance.

5. Rhetoric — Engineering Communication Done Responsibly

Rhetoric is how reasoning is presented so people understand and accept it.

Good rhetoric:

  • Matches the audience’s technical depth
  • Uses familiar language
  • Frames tradeoffs clearly
  • Avoids unnecessary jargon

Examples:

  • To management: This reduces outage risk and restores vendor support.
  • To engineers: This removes a single point of failure and re-establishes patching and monitoring.

Rhetoric does not replace logic — it delivers logic.

Part 2 — Technical Planning: Reasoning Applied to Systems

Technical planning is formal reasoning applied to engineering systems.

It answers:

What do we need, where does it fit, how does it connect, what can fail, and how do we know it worked?

1. Requirement — What must this do?

Defines the problem to be solved.

Examples:

  • Replace end-of-life switches in an IDF
  • Add Wi-Fi capacity to a gym
  • Improve WAN resiliency for a municipal office

This anchors all future decisions.

2. Environment — What system does this live in?

Defines context and constraints:

  • Existing topology
  • IP addressing and VLANs
  • Legacy hardware
  • Power, cooling, and space
  • Staffing and operational maturity

A solution that ignores environment will fail.

3. Interfaces — What does it connect to?

Defines integration points:

  • Uplinks (1G / 10G, fiber or copper)
  • VLANs, SVIs, VRFs
  • DHCP, DNS, RADIUS
  • Monitoring, logging, APIs

Most failures occur at interfaces.

4. Knowns — What information is reliable?

Examples:

  • Port counts
  • PoE device inventory
  • Traffic patterns
  • Existing configurations

Knowns anchor the design in reality.

5. Unknowns — What must be discovered?

Examples:

  • Actual PoE draw
  • Fiber type
  • Feature usage
  • Licensing limitations

Unknowns drive site surveys, audits, and lab testing.

6. Risks — What can go wrong?

Risks are evaluated by:

  • Likelihood
  • Impact

Examples:

  • Downtime during cutover
  • Insufficient PoE
  • Firmware instability
  • Vendor lock-in

High-impact risks must be mitigated or redesigned.

7. Potential Problems (Pre-Mortem) — How could this fail?

Assume the project failed and ask why:

  • DHCP scope exhaustion
  • STP loops
  • Authentication failures
  • Misconfigured uplinks

This is proactive engineering, not pessimism.

8. Solution Design — Given all of the above, what fits?

Only after requirements, constraints, and risks are known do you choose:

  • Vendor
  • Hardware model
  • Architecture
  • Deployment method

This prevents solution-first thinking.

9. Verification — How do we know it worked?

Define success criteria:

  • Connectivity tests
  • Authentication tests
  • Monitoring visibility
  • Performance validation

Verification turns deployment into engineering.

10. Rollback — How do we undo this safely?

Every plan needs an exit:

  • Config backups
  • Old hardware staged
  • Clear reversion steps

Rollback planning is a sign of professional discipline.

Why This Matters for Network Engineers

Good engineers do much of this intuitively.
Great engineers make it explicit and repeatable.

Formal technical planning:

  • Reduces outages
  • Improves reliability
  • Makes decisions defensible
  • Scales from SMB to enterprise
  • Builds trust with stakeholders

Ultimately, it gives you clarity under pressure —
which is the core of engineering judgment.