Azure Local Network Gateway
A Local Network Gateway is a sub resource of a Azure Virtual Network Gateway, that represents a on-premises location for the used in tandem with a Azure Connection resource in the creation of a Virtual Private Network or Azure Virtual Network Gateway Connection.
The Address Space declared can be one or more CIDR formatted subnets. If you plan to use this Local Network Gateway in a BGP-enabled connection, the minimum prefix to declare is the host address of your BP Peer IP address on your BPN device.