A transit VNET is a common strategy to connect multiple, geographically disperse vNETS and remote networks. It simplifies network management and minimizes the number of connections required to connect multiple VNETs and remote networks.
Microsoft Azure VNETs leverages Virtual Network (VNET) peering to establish communication between VNETs. Microsoft Azure Transit vNET, known as Gateway Transit, is a centralized vNET, connecting multiple spoke vNETs.
Cisco Transit vNET solution on Azure uses a pair of Cisco CSR1000v devices acting as DMVPN Hubs in active-active mode. The spoke VNETs also have a Cisco CSR1000v acting as DMVPN Spoke connecting to both the CSR1000v devices in the Hub vNET through routing overlays such as EIGRP and BGP. This solution does not require manual configuration and is fully automated. Once deployed, this solution automatically creates dynamic spoke-to-spoke IPsec tunnels in an on-demand fashion. This solution on Microsoft Azure is introduced on CSR100v starting with IOS-XE release 16.9.x
The Cisco Cloud Services Router (CSR) 1000v is a full-featured Cisco IOS XE virtual form factor router, enabling enterprise-class networking services in the Azure cloud.