Software Defined Networking

Everything you need to design, build, and run a Cisco SD-Access campus fabric — even if you have never touched one.

Most SD-Access material either drowns you in acronyms or assumes you already know the answer. SDA Fundamentals does the opposite. It takes one realistic company — Northforge Industrial, a mid-size manufacturer with offices, a plant floor full of OT and IoT, a warehouse, and small sales sites — and walks you through its entire fabric project, from the first design meeting to day-two operations. Every concept is introduced when the project needs it, defined in plain language, and applied to a real problem you can see.


By the end you will be able to:

- Explain the fabric from first principles — underlay and overlay, LISP (the control plane), VXLAN (the data plane), and TrustSec / SGTs (the policy plane) — and know exactly what each one does and why.
- Design a fabric that fits real requirements: virtual networks, groups, the policy matrix, address pools, role placement, wireless, transit, and identity — assembled into a High-Level Design you could hand to a client.
- Stand up the foundation with Catalyst Center and ISE, build the underlay (LAN Automation or manual), and provision the fabric — in the correct, dependency-driven order.
- Bring sites online both ways — a clean greenfield build, and a brownfield migration of a live campus with zero production downtime, using the Layer 2 handoff and a wave-based rollout.
- Segment the network for real — macro-segmentation with virtual networks, micro-segmentation with SGACLs, guest and contractor isolation, and the fusion pattern for shared services — then prove it works by testing the denies.
- Fold in wireless, security, and multi-site — fabric-enabled wireless, an identity-first security model with Rapid Threat Containment, and carrying segmentation across the WAN.
- Operate, automate, and troubleshoot — Catalyst Center Assurance, a layered bottom-up troubleshooting method with three concrete playbooks, and running the fabric as code with the REST API, Python, and Ansible.

What's inside

- 10 chapters taking one project from design to operations, plus a Conclusion, four appendices (reference design, command reference, deployment checklists, frequently-confused concepts), a glossary, and a standards & further-reading guide.
- Original diagrams for every key idea — nothing copied, everything drawn to teach.
- Runnable, realistic CLI and config snippets using safe documentation IP ranges.
- Watch out," "Common Problem," "From the Field," and "Design Tip" notes throughout — the hard-won lessons that separate a fabric that works from one that merely builds.

Who it's for

Network engineers, architects, and students who are comfortable with traditional networking (VLANs, routing, switching) and want to become fluent in SD-Access. If you can configure a traditional campus, you can follow this book — and by the end, design, secure, and operate a fabric of your own.


A note

This is an independent, educational work. It is not affiliated with, authorised by, or endorsed by Cisco Systems, Inc. All companies, addresses, and configurations are fictional and for illustration; all diagrams are original.

Read the free sample for the complete Chapter 1, then grab the full book and build your first fabric.

Most SD-WAN material teaches you the features. This book teaches you the project. SD-WAN Fundamentals walks you through the entire lifecycle of a real Cisco Catalyst SD-WAN (Viptela) deployment — from the first design meeting to the thousandth day of operations — by following one fictional company, Meridian, as it migrates a live 40-site retail estate onto the fabric without taking the business down. This is a practitioner's field guide, not an exam cram. There are no quizzes and no memorisation drills — just the mental models, design decisions, real configurations, and hard-won habits you need to run a project like this yourself. What you'll learn: How the fabric actually works — control plane vs data plane, OMP, TLOCs, colors, IPsec, BFD, and end-to-end segmentation, explained so they finally click.

How to design against requirements — transport, topology, segmentation, controller sizing, addressing, and certificates, captured in a real high-level design.

How to build and migrate safely — stand up controllers, onboard your first edge with zero-touch provisioning, and migrate live sites in waves with a clean rollback at every step.

How to steer traffic — centralized control policies for topology, and data policies with Application-Aware Routing, Direct Internet Access, QoS, and service chaining.

How to secure and prove it — segmentation as security, the embedded security stack, secure Direct Internet Access, and a compliance story you can demonstrate live.

How to extend and operate it — cloud on-ramp for IaaS and SaaS, when (and when not) to adopt advanced features, and a complete monitoring and troubleshooting playbook.

Who it's for: Network engineers and architects moving into SD-WAN, anyone about to run or support a Catalyst SD-WAN deployment, and experienced engineers who want a clear, opinionated, project-shaped reference instead of scattered documentation.

Inside the book: Ten chapters, a single end-to-end project narrative, real IOS XE configurations, 60+ original diagrams, a three-part troubleshooting playbook, and a glossary of every key term. The technology is Cisco Catalyst SD-WAN — but the deeper discipline is portable to any platform and to any serious network engineering.