EVPN/VXLAN Fabric

Primary Backends

• pyats-network
• pyats-routing
• pyats-topology
• netbox-reconcile

Focus Areas

• VTEP reachability and loopback consistency
• VXLAN VNI to VLAN mapping
• EVPN route types 2, 3, and 5
• Anycast gateway consistency
• Multihoming and Ethernet Segment state
• Underlay routing health vs overlay symptoms

When to Use

• EVPN MAC/IP reachability issues
• Silent hosts or asymmetric flooding complaints
• Anycast gateway or ARP suppression problems
• Leaf-spine underlay failures impacting overlay forwarding
• Data-center fabric audit and documentation

Workflow: Overlay Reachability

1. Verify underlay reachability between VTEPs.
2. Check BGP EVPN session health and route-type presence.
3. Validate VNI mapping, bridge domains, and anycast gateway settings.
4. Cross-check local MAC learning against EVPN advertisements.
5. Reconcile intended VLAN/VNI mappings against NetBox or ACI intent.

Workflow: Multihoming / ESI Trouble

1. Confirm the access device and leaf pair are both healthy.
2. Validate Ethernet Segment identifiers and DF election state.
3. Check for duplicate MAC movement or split-horizon symptoms.
4. Verify LACP state, access VLANs, and host-facing port consistency.

Important Rules

• Always validate the underlay before blaming the overlay
• Do not push fabric config without approved change control
• Use route-type evidence, not assumptions, to explain forwarding