Update Adventure Works RI Networking Information

docs/reference/adventureworks/README.md

@@ -6,7 +6,13 @@
 
 The Enterprise-Scale architecture is modular by design and allow organizations to start with foundational landing zones that support their application portfolios and add hybrid connectivity with ExpressRoute or VPN when required. Alternatively, organizations can start with an Enterprise-Scale architecture based on the traditional hub and spoke network topology if customers require hybrid connectivity to on-premises locations from the beginning.
 
-This reference implementation also allows the deployment of platform services across Availability Zones (such as VPN or ExpressRoute gateways) to increase availability uptime of such services. 
+A hub and spoke network topology allows you to create a central Hub VNet that contains shared networking components (such as Azure Firewall, ExpressRoute and VPN Gateways) that can then be used by spoke VNets, connected to the Hub VNet via VNET Peering, to centralize connectivity in your environment. Gateway transit in VNet peering allows spokes to have connectivity to/from on-premises via ExpressRoute or VPN, and also, [transitive connectivity](https://azure.microsoft.com/en-us/blog/create-a-transit-vnet-using-vnet-peering/) across spokes can be implemented by deploying User Defined Routes (UDR) on the spokes and using Azure Firewall or an NVA in the hub as the transit resource. Hub and spoke network design considerations & recommendations can be found [here](https://docs.microsoft.com/en-us/azure/cloud-adoption-framework/ready/azure-best-practices/traditional-azure-networking-topology).
+
+![Hub & Spoke Network Topology](./media/hub-and-spoke-topology.png)
+
+*A hub & spoke network topology*
+
+This reference implementation also allows the deployment of platform services across Availability Zones (such as Azure Firewall, VPN or ExpressRoute gateways) to increase availability uptime of such services.
 
 ## Customer profile
 
@@ -72,6 +78,8 @@ By default, all recommendations are enabled and you must explicitly disable them
 
 ![Enterprise-Scale with connectivity](./media/es-hubspoke.png)
 
+> For a detailed networking topology diagram for this reference implementation click [here](../../media/es-hubspoke-nw.png)
+
 ## Next steps
 
 ### From an application perspective