EVPN: BGP says where every host is, VXLAN takes it there
Every mechanism has a step-by-step animation, the configuration explained line by line and the exam notes. Where a parameter changes the outcome, you get a simulator where you change it yourself.
TL;DR
EVPN is a BGP control plane (the L2VPN EVPN family, AFI 25 / SAFI 70) for MAC and IP addresses: each VTEP advertises its local hosts as type 2 routes, so the other VTEPs know in advance where to send, with no flood-and-learn. The encapsulation is VXLAN in data centers (UDP 4789, 24-bit VNI, 50 extra bytes) or MPLS at service providers. Type 3 routes organize BUM traffic (ingress replication or multicast), type 5 carries prefixes, types 1 and 4 do all-active multihoming with a DF and mass withdraw. On top of that: ARP suppression, mobility with sequence numbers and duplicate detection, distributed anycast gateway with symmetric IRB through the L3VNI, border leaves toward the outside and Multi-Site between fabrics. The classic incidents: MTU 1500 in the underlay, mismatched auto route-target between ASes, missing send-community, missing PIM with mcast-group.
How to read the notes: red = critical for the exam, green = theory, blue = numbers, yellow = pitfalls, cyan = differences between platforms (NX-OS, IOS-XE, IOS-XR) and RFCs. In the animations, the configuration lines used at the current step are highlighted automatically; the ← → arrows change the step while the animation is focused.
The analogy, in short
Think of a hotel chain in a city, with a central guest registry: when someone checks in, their front desk sends a card to the registry, which copies it to every hotel with the same wing. Messages between guests travel on the streets in sealed envelopes with the hotel's address on the outside; nobody shouts across the whole chain anymore to find out where someone is.
The model holds up to §10. From §11 on (MPLS labels, Multi-Site, RT constraint), it stretches; see the full analogy and its limits in §16.