VXLAN EVPN Troubleshooting: What Actually Breaks
Four faults hit in a real Nexus fabric, the output that identified them, and an ordered method for the next one.
VXLAN
The overlay encapsulation behind every modern fabric, 50 bytes of header that turn a routed underlay into a stretched Layer 2 domain. Articles tagged VXLAN cover L2VNI and L3VNI config, packet walks and MTU traps.
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EVPN L3VNI and the Distributed Anycast Gateway
Symmetric IRB routes between VNIs on the leaf that receives the packet. Here is the L3VNI build and the real output that proves it worked.
A Real VXLAN Packet, Header by Header
A genuine VXLAN packet captured between a spine and a leaf, taken apart byte by byte from the outer MAC down to the ICMP echo request inside.
VXLAN L2VNI Configuration on Nexus, Proven
An L2VNI build on a real Nexus fabric, including the vPC anycast VTEP mistake that produced an empty peer table and how it was fixed.
BGP EVPN Route Types Explained with Real Output
EVPN route types stop being abstract the moment you read them off a real fabric. Here are Types 2, 3 and 5 from a working Nexus lab.
Ingress Replication vs PIM Anycast RP in VXLAN
BUM traffic still has to get everywhere in a VXLAN fabric. Here is how ingress replication handles it, and what you give up by not running PIM.