Terminology
Underlay= Physical Network interconnected with L3 Routing Protocol (BGP) to provide a robust, fast, redundant network. No features are installed here.
Overlay = Virtual Network running on top of Underlay. Allows host-IP to be much more mobile as well.
Anycast Gateway : One IP for multiple gateways. This avoid hairpinning.
AS : BGP Autonomous System Number : Depending on same or different BGP-ID. BGP connections are viewed as internal or external
VTEP : Point of Entry/Exit between Underlay and Overlay
VLTi : Layer 2 Interconnect Between two Dell OS10 Switches. Similar to vPC on Cisco Nexus switches.
VRF : Virtual Routing and Forwarind : Each VRF has it’s own routing table in a router allowing different behaviour for same destination. An interface can not be in two VRF’s at the same time.
BFD : Failover detection of links. Used here to accelerate BGP-Down/Up Response.
