The intent of this book is to explain various design models for Overlay Network and Underlay Network used in VXLAN Fabric with BGP EVPN Control-Plane. The first two chapters are focusing on the Underlay Network solution. The OSPF is introduced first. Among other things, the book explains how OSPF flooding can be minimized with area design. After OSPF there is a chapter about BGP in the Underlay network. Both OSPF and BGP are covered deeply and things like convergence are discussed. After the Underlay Network part, the book focuses on BGP design. It explains the following models: (a) BGP Multi-AS with OSPF Underlay, this chapter discusses two design models – Shared Spine ASN and Unique Spien ASN, (b) BGP-Only Multi-ASN where both direct and loopback overlay BGP peering models are explained, (c) Single-ASN with OSPF Underlay, (d) Hybrid-ASN with OSPF Underlay – Pod-specific shared ASN connected via Super-Spine layer using eBGP peering, (e) Dual-ASN model where leafs share the same ASN and spines share their ASN. Each of the design model chapters includes a “Complexity Map” that should help readers to understand the complexity of each solution. This book also explains BGP ECMP and related to ECMP, the book also covers ESI Multihoming. The last chapter introduces how two Pods, can also be geographically dispersed DCs, can be connected using Layer 3 only DCI with MPLS.

I am using 5-stage Clos topology throughout the book. Some solutions are though explained by using only three switches for the sake of simplicity. I am also using IP-Only Underlay Network with Ingress-Replication, so this book does not cover Underlay Network Multicast solution. Besides, I am not covering DCI using Layer 2 Border Gateway (BGW) or Overlay Tenant Routing Multicast solution in this book because those, among the Underlay Multicast solutions, are covered in my first book “Virtual Extensible LAN – VXLAN: A Practical Guide to VXLAN solution” that is available at Amazon and Leanpub.

I wanted to keep the focus of the book fairly narrow and concentrate on the Control-Plane design and functionality. Please be aware that this book does not give any recommendation to which solution is the best and which is not. It is the readers' responsibility to find that out and selects the best solution for their needs. The book includes 66 full-color images, 260 configuration/show command examples, and 32 packet captures.