Application Delivery and Load Balancing in Microsoft Azure

Chapter 5. Azure Front Door with NGINX

What Is the Azure Front Door Service?

Azure Front Door is a service that provides global web traffic routing, optimized for performance and high availability failover. Front Door is useful in all types of scenarios, especially multiregional deployments. As the name implies, Front Door is meant to be the first and primary access point between your client and your web service. Front Door always answers your client with a local connection, and then works as an operator to connect the client to the closest available next hop for that request. By acting as a configurable distributed proxy, Front Door enables you to have Layer 7 routing and network control at the edge.

Front Door uses latency-based DNS routing to connect the client to the nearest Front Door POP, or point of presence. POP locations differ from regions in that there are more of them, and they are distributed to be closer to the user. Latency-based routing is used for the backend connection as well, routing client requests to the nearest installation to a given service, wherever in the world it may be. Being health aware, Front Door automatically enables multiregion failover. Backend pools can be constructed with a number of different Azure services and internet standard endpoints. What makes Azure Front Door special is that it is network-optimized by use of a split TCP-based anycast protocol.

Split TCP

Split TCP is a technique aimed at reducing latency packet delivery issues by ...