ExpressRoute Fast Path

ExpressRoute FastPath

Express Route FastPath is used to increase or improve the performance between Enterprise On-Premises Network and your Virtual Network. 

When the ExpressRoute FastPath is enabled it sends the network traffic directly to a virtual machine in the Virtual network , bypassing the gateway. 

FastPath is available on all ExpressRoute Circuit. 

FastPath requires the Virtual Network gateway to exchange the routes between Virtual network and On-Premises Network.Below are Gateway models used when an Enterprise decides to enable FastPath.

• Ultra Performance 
• ErGw3AZ

 Below are some features that are not supported by FastPath.   

• Basic Load Balancer: If an Enterprise decides to deploy a basic load balancer in VNet or on Azure PaaS service which Enterprise has deployed in VNets that uses an Internal load balancer.  The Traffic from On-Premises Network to Virtual IP hosted on basic Load Balancer will be sent to Virtual network Gateway.  
• Private Link : If an Enterprise connects to a private endpoint in its Virtual Network from On-Premises Network , Over a non-100 Gbps Express Route Direct Circuit . The Connection will always go via Virtual network gateway. FastPath connectivity to a private endpoint over a 100 Gbps ExpressRoute Direct Circuit is supported.