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Network & Security Architecture

Networks that perform under load. And hold up under attack.

Spine/Leaf data center fabrics, EVPN-VXLAN overlays, zero-trust segmentation, campus refreshes and multi-site WAN - architected for the workloads you have today and the scale you'll need in five years. Four data centers migrated with zero production downtime. The fabric that didn't make the news is the one we built.

Why architecture matters now

Cabling decisions made today still cost you in 2035.

The network architectures most enterprises run were designed for a workload mix that no longer exists. Three-tier hierarchies built for client-server traffic now carry east-west AI inference and microservice meshes that hammer the spine. Flat VLAN-everywhere campuses now face zero-trust mandates they were never designed to enforce. The cost of running the wrong architecture isn't dramatic - it's small, daily friction that compounds for a decade.

A modern enterprise network is a Spine/Leaf core with an EVPN-VXLAN overlay, identity-aware segmentation enforced at the access layer, and a converged policy plane that follows the workload across data center, campus and cloud. We architect to that target and migrate to it in phases - never with a big-bang cutover.

What we deliver

From rack diagrams to running fabric.

/ 01

Spine/Leaf data center design

Non-blocking Spine/Leaf fabrics sized to your east-west workload, growth trajectory and failure-domain requirements. We design for the platform you'll actually operate - not a generic reference architecture lifted from a vendor whitepaper.

/ 02

EVPN-VXLAN deployment

EVPN-VXLAN control plane with BGP route reflectors, ingress / egress replication strategies, multi-tenancy by VRF, and integration with existing L2/L3 infrastructure. Designed so day-two operations are as simple as day-one cabling.

/ 03

Cisco ACI & NDFC operations

Greenfield ACI fabrics, migrations to NDFC, application network profile design, contract architecture, and integration with VMware and ServiceNow. Plus rescue work on ACI deployments that aren't behaving as advertised.

/ 04

Zero-trust segmentation

Identity-aware microsegmentation using ISE, Aruba ClearPass, Cisco TrustSec or NSX. Workload-to-workload policy, lateral-movement containment and compliance-grade evidence for PCI, HIPAA and NIST.

/ 05

Campus network redesign

EVPN-VXLAN campus cores, Cisco SD-Access, converged wired/wireless policy, multi-site templates and access-layer refresh. 802.1X, WPA3-Enterprise and NAC integration baked in from design phase.

/ 06

Multi-site WAN architecture

SD-WAN underlay design, MPLS displacement plans, ExpressRoute and Direct Connect integration, dual-ISP hub-and-spoke or full-mesh topologies. Resilient routing for organisations that can't afford a regional outage.

Selected work

Four enterprise data centers migrated to Spine/Leaf. Zero production downtime.

Four enterprises - a Tier-1 casino operator, a regional medical group, a wholesale ISP and an oil-and-gas major - separately engaged us to retire end-of-life three-tier data centers and replace them with modern Spine/Leaf fabrics. Each environment had irreplaceable workloads, regulatory exposure and zero tolerance for downtime.

We architected non-blocking Spine/Leaf fabrics - three on Cisco ACI, one on Arista with EVPN-VXLAN - designed phased workload migration with rollback gates at every step, and ran the old and new fabrics in parallel until the new platform had operated under real production load for 30 days. Every one of the four migrations delivered with zero production downtime. As-built documentation handed over at the end is what those internal teams now run from.

Read the full case study
Technology stack

Deep across Cisco, Arista, Juniper and Aruba.

Multi-vendor by design. We recommend the platform that fits your operational team's skills and your scale requirements - not the vendor we have margin on.

Data Center Fabric

Core
Cisco ACI Cisco NDFC / DCNM Cisco Nexus 9000 Arista EOS Arista CloudVision Juniper Apstra

Overlays & Control Plane

Core
EVPN-VXLAN VxLAN flood-and-learn BGP / iBGP RR OSPF / IS-IS Underlay MP-BGP

Campus & Access

Specialty
Cisco SD-Access Aruba CX Cisco Catalyst 9000 Arista Cognitive Campus Juniper Mist

Segmentation

Specialty
Cisco ISE TrustSec VMware NSX Illumio Aruba ClearPass SGT / ACL

Automation

Specialty
Arista AVD Ansible Terraform Cisco DNAC Python / NETCONF

Monitoring & Telemetry

Core
CloudVision Cisco DNAC SolarWinds PRTG LogicMonitor Streaming Telemetry
How we work

Architecture engagements run in five phases. Every phase has an exit gate.

/ Phase 01

Discovery & current-state audit

Topology mapping, traffic-flow analysis, application dependencies, failure modes, growth forecasts. We document what's actually running - not what was documented years ago.

/ Phase 02

Target architecture & vendor selection

Spine/Leaf sizing, overlay design, segmentation model, multi-site topology. Vendor selection emerges from the requirements - not a pre-decided shortlist.

/ Phase 03

Lab build & validation

Full lab buildout with failure scenarios, automation pipelines, monitoring validation and cutover plan rehearsal. The new platform proves itself before it touches production.

/ Phase 04

Phased production migration

Workload-by-workload migration with parallel run periods, rollback gates and on-call playbooks at each phase. The old fabric stays live until the new fabric has run real load for at least 30 days.

/ Phase 05

Handover, runbooks & hypercare

As-built diagrams, configuration repositories, monitoring dashboards, operational runbooks and 30/60/90 hypercare. Your team operates the platform end-to-end before we step back.

Frequently asked

The questions network architects ask us first.

When does Spine/Leaf make sense versus a traditional three-tier design?

Spine/Leaf is the right choice when east-west traffic dominates (any modern data center with virtualization, microservices or AI workloads), when you need predictable any-to-any latency, or when you're planning for 10×+ growth without re-cabling. Three-tier still works for legacy north-south workloads, small footprints under 200 ports, or environments not refreshing for another five years.

Do we need EVPN VXLAN, or just VXLAN?

EVPN is the control plane that makes VXLAN viable at scale. Without EVPN, you're back to flood-and-learn - operationally painful past about 20 leaf switches. We deploy EVPN-VXLAN by default for any new Spine/Leaf and recommend retrofitting legacy VXLAN-without-EVPN deployments unless they're already small and stable.

Can a data center migration really be done with zero downtime?

Yes - and we've done it. The trick is phased workload migration with parallel run periods, not big-bang cutovers. We design the new fabric, build connectivity between old and new, migrate by workload group with rollback gates, and decommission only after the new platform has run under real load. We've delivered four enterprise data center migrations to Spine/Leaf with zero production downtime.

Should we run Cisco ACI, NDFC or open EVPN-VXLAN?

ACI is the most operationally complete option if you're committed to Cisco and willing to operate Cisco's policy abstraction. NDFC is the right answer for Cisco-aligned teams who want VXLAN without ACI's complexity. Open EVPN-VXLAN on Arista or Juniper is best if vendor neutrality matters or if your team is comfortable with config-as-code automation. We design and operate all three.

What about microsegmentation - do we need it?

Microsegmentation is the right answer for regulated industries (PCI, HIPAA, NIST), for environments with crown-jewel workloads, and for organisations that have suffered a ransomware incident. For everyone else, VLAN + ACL or ISE-enforced segmentation is often sufficient. We help you make the tradeoff between security posture, operational overhead and cost honestly.

How do you handle campus redesigns at scale?

Campus engagements typically combine an EVPN-VXLAN core (or Cisco SD-Access fabric) with refreshed access layer, WPA3-Enterprise or 802.1X, NAC enforcement, and converged wired/wireless policy. Multi-site campus rollouts phase by location, with each site's design templated from the master architecture for consistency and operational simplicity.

Talk to a network architect

Bring us in before the procurement RFP. Or after.

30-minute call with someone who's actually built one of these. Honest read on whether your target architecture fits your operational reality.