A virtual hub option, set to ExpressRoute by default or to VPN or AS Path, that decides between on-premises routes with the same prefix once longest prefix match and the static-over-BGP rule have been applied.
Also called HRP.
Read more: Microsoft Learn
In the Ultra Transcenders books
Each book explains Hub routing preference in context, with comparison tables and the common traps.
Terms in this definition
- Virtual hub
Inside a Virtual WAN, a VNet managed by Microsoft that contains the hub router plus the VPN, ExpressRoute and User VPN gateways. Typically there is one per region, but several hubs can share a region.
- Set
Secret permission in Key Vault for writing secrets; some older material refers to it as Create.
- ExpressRoute
A dedicated private link between on-premises networks and Azure, using Microsoft peering or private peering.
- VPN
Traffic sent through an encrypted tunnel across a public network, as in a site-to-site connection to a VPN gateway in an Azure GatewaySubnet.
- AS path
BGP attribute recording each ASN a route has passed through. Routes with shorter paths usually win, so adding extra ASNs makes one look less attractive.
- Longest prefix match
How Azure chooses between routes: if more than one matches a destination, the most specific prefix is used. That is why a 0.0.0.0/0 UDR leaves traffic inside the VNet untouched.