Business Services — Architecture
Network Architecture & Design
Purposefully designed network architecture — high-level and low-level, vendor-neutral, built to support operational needs today and remain maintainable as requirements evolve.
What This Service Addresses
Network architecture decisions made during initial deployment tend to persist — and to limit — what is possible later. Organisations that grew quickly often have infrastructure that was never designed for its current scale. Those undertaking significant change — migration, expansion, compliance remediation — need a design that actually supports the intended outcome, not just a documentation exercise.
This service produces network architecture that is functional, defensible, and implementable. The deliverable is not a conceptual diagram — it is a design with sufficient technical depth to be handed to an implementation team and built.
Scope of the Design Engagement
- High-level design (HLD) — the architectural framework: topology, segmentation model, security zones, redundancy strategy, and key technology decisions with rationale
- Low-level design (LLD) — the implementation detail: addressing schemes, VLAN definitions, routing design, firewall zone policies, interface configurations, and protocol parameters
- Segmentation design — mapping of network segments to business function and risk profile, defining traffic flows and access controls between zones
- Redundancy and resilience planning — identification of single points of failure, design of redundant paths, and failover mechanisms appropriate to the availability requirements
- Security zone definition — definition of trust zones, DMZ architecture, and internal segmentation that limits lateral movement and contains the blast radius of a potential breach
- Vendor-neutral technology evaluation — where technology selection is in scope, evaluation of available options against requirements — without preference for any particular vendor
- Compliance alignment — design decisions mapped to DORA, NIS2, or other applicable requirements where relevant
What Good Architecture Looks Like
A well-designed network has several identifiable characteristics. It can be explained clearly — someone who did not design it can understand how it works and why the key decisions were made. It has defined boundaries — traffic flows between segments in predictable, controlled ways. It has a coherent security model — the design limits what is possible in the event of a compromise, not just what is possible under normal operation. And it is maintainable — it can be extended, changed, and operated by the team responsible for it, without requiring the original designer.
These characteristics are not accidents — they are design decisions made deliberately. This engagement produces architecture with all of them.
What You Receive
- High-level design document — architectural overview with topology diagrams, segmentation model, and key technology decisions with rationale
- Low-level design document — complete implementation specification including addressing, VLANs, routing, firewall policy framework, and protocol design
- Network topology diagrams — logical and physical diagrams to the appropriate level of detail
- Security zone definition — documented trust model with defined inter-zone access policies
- Implementation notes — guidance for the team performing the build, including change sequencing and risk areas
- Design review session — walkthrough of the design with key stakeholders before implementation begins
Typical Situations
- Greenfield builds — new office, data centre, or cloud presence requiring a complete network design from the ground up
- Redesign following assessment — organisations that have completed a network assessment and need the identified issues resolved through a structured redesign
- Compliance-driven redesign — organisations needing to implement segmentation, access control, or resilience improvements to meet DORA, NIS2, or other framework requirements
- Cloud migration preparation — designing the on-premises and hybrid connectivity architecture before migrating workloads
- Site expansion — adding new locations to an existing network in a way that is architecturally consistent with the existing design
"Architecture is not documentation of what was built. It is the specification for what should be built — and the reasoning that makes it possible to build it correctly."
Delivery
Architecture engagements are delivered remotely. The process begins with a requirements and constraints workshop — typically 2–4 hours — to understand the business context, technical environment, compliance requirements, and operational constraints. From that foundation, the design is developed iteratively with review checkpoints before finalisation.
Typical engagement duration is 2–4 weeks depending on scope. The design is produced before any implementation work begins, and is structured to serve as the authoritative reference throughout implementation.
Frequently Asked Questions
What is the difference between HLD and LLD?
A High-Level Design (HLD) defines the overall architecture — zones, traffic flows, technology choices, and logical topology. A Low-Level Design (LLD) translates that into specific implementation detail: device configurations, interface assignments, routing, and security policies. Both can be delivered depending on what stage your project is at.
Is the design vendor-neutral?
Yes. Architecture work is vendor-neutral and not tied to any product line. Equipment recommendations, where made, are based on technical fit for the environment — not commercial relationships.
What information is needed to start?
Current network diagrams (even rough ones), a description of the problem being solved or the outcome required, equipment inventory, and any known constraints such as budget, compliance requirements, or existing vendor agreements.
Do you also handle implementation?
Implementation support is available as a separate engagement. Designs include documentation that allows your own team or a third party to implement — keeping the design and build stages clearly distinct.
