Campus SONiC EVPN-VXLAN Fabric

Stand up a compact enterprise EVPN-VXLAN pod — 2 spines, 2 leaves, 2 PCs — and watch two hosts on different leaves reach each other across a stretched L2 overlay. Same EVPN-VXLAN building blocks as the AI fabric, at campus scale, on its own dedicated topology.

• EVPN-VXLAN at campus scale — the same overlay primitives as a hyperscale fabric, 2x2
• A stretched L2 segment (VNI 10100) across two leaves
• Reading Type-2/Type-3 EVPN routes on a small pod
• Proving overlay reachability with a cross-leaf host ping

Carve the campus access layer into per-device-class VLANs — workstations, IP phones, PoE cameras, and wireless APs — each stretched as its own EVPN-VXLAN segment across both leaves. Same-VLAN devices reach each other across the fabric; the classes stay isolated from one another (no inter-VLAN routing yet — that's the next module's anycast gateway).

• Per-device-class VLAN segmentation (data / voice / camera / wireless)
• Stretching multiple L2VNIs across leaves with advertise-all-vni
• Access ports as untagged PVID members of a vlan-aware bridge
• Why isolation is the default — and what it takes to cross VLANs (next module)

Give the segmented campus a distributed anycast gateway — a per-VLAN SVI carrying the same gateway IP and MAC on every leaf — so each endpoint's default gateway is local on its own switch and the device classes can route to one another, same-leaf and across leaves, over the EVPN-VXLAN fabric.

• Distributed anycast gateway — same gateway IP + MAC on every leaf
• Inter-VLAN routing at the ingress leaf, then bridge over EVPN
• Why a local-everywhere gateway beats a single centralized router
• Controlled reachability between device classes (vs. module 2's isolation)

Hand out addresses dynamically: turn each leaf into a DHCP relay agent that forwards the access endpoints' requests across the L3 boundary to a central DHCP server, and watch workstations, phones, cameras, and APs lease their address — and the right gateway — through the relay.

• Why DHCP needs a relay across subnets — the broadcast boundary
• giaddr: how the relay tells the server which subnet to serve
• Configuring a leaf as a DHCP relay agent to a central server
• Dynamic addressing per device class, with the correct gateway option