EVPN
What the EVPN domain tests
JNCIP-ENT tests EVPN control-plane concepts and Junos configuration: MP-BGP EVPN routes, VXLAN data plane, route targets, ESI multihoming, and anycast gateways. You must explain why a MAC or IP prefix is missing from a remote VTEP.
Core rules
- EVPN uses MP-BGP with AFI 25 and SAFI 70; common route types are 1 (auto-discovery), 2 (MAC/IP), 3 (inclusive multicast), 4 (Ethernet segment), and 5 (IP prefix).
- Type 2 routes advertise MAC and optionally IP; Type 5 advertises IP prefixes for routing.
- VNIs map to VLANs or VRFs; route targets control import and export between EVPN instances.
- ESI identifies a multihomed Ethernet segment; all-active and single-active modes affect forwarding.
- Anycast gateway uses the same IP and MAC on all VTEPs to avoid traffic tromboning.
Worked example
A VM MAC is learned locally but not on a remote VTEP. The local Type 2 route is generated, but the remote VTEP imports nothing. The route target on the local EVPN instance does not match the remote import target. Correcting the route target makes the Type 2 route acceptable; the remote VTEP installs the MAC and VXLAN forwarding works. The VNI mismatch would be a separate data-plane fault.
Traps
Do not confuse a VLAN ID with a VNI. Do not assume Type 2 carries all IP prefixes; Type 5 is for prefix routing. Do not ignore route-target direction. Check ESI and designated forwarder state in multihomed designs.