From Classic L3VPN to EVPN: Mastering Type 5 Routes on the Backbone#

Samuel Emanuel Urbano Tomassoni, Fernando Neiverth

• Why: This is the talk in the program squarely inside physical datacenter/campus fabric design — eliminating the centralized-L3-gateway tromboning problem in a leaf-spine EVPN-VXLAN fabric.
• What: A migration from an edge running EVPN-VXLAN as "dumb" L2 transport with IRB gateways concentrated on a heavy core router, to distributed anycast gateways extended to the leaf/edge switches using EVPN Type 5 (IP prefix) routes. Reported control-plane effect on their network: the bgp.evpn table dropped from 141,156 routes (Type-2 host routes) to 276 summarized Type-5 advertisements — over 99% reduction. Spines act as route reflectors, removing full-mesh iBGP.
• How: First-hop routing at the network edge via distributed anycast IRB on the leaves; Type-5 IP-prefix advertisements associated with BGP communities for granular inter-VRF traffic control; the EVPN control plane is decoupled from transport, so the underlay can move from VXLAN to SR-MPLS or SRv6 without refactoring edge configurations; BUM and management traffic confined to the edge.
• Where applicable: Leaf-spine datacenter and campus fabrics with routing-capable (EVPN Type-5 capable) edge switches. The before/after route counts are from the presenters' own network — org-specific — but the design pattern and the Type-2-to-Type-5 summarization argument are general.