RIFT: Routing in Fat Trees + RIFT Auto-EVPN — draft-ietf-rift-rift, draft-ietf-rift-auto-evpn#
IETF 123 (Madrid) digest Program Wildcard pick Madrid · 19–25 July 2025
- Tier: Wildcard
- Why: You wouldn't go searching for a brand-new IGP, but RIFT is genuinely novel: a routing protocol purpose-built for Clos/fat-tree DC fabrics rather than retrofitted (like BGP-in-the-DC). It's link-state northbound and distance-vector southbound, which is an elegant fit for the topology. Auto-EVPN layering on top is a tell that it's aiming at real DC deployment, not just academic interest.
- What: A fat-tree-specific routing protocol; the auto-EVPN draft automates EVPN service provisioning over a RIFT underlay. (from abstract only)
- How: Exploits the regularity of fat-tree topologies to minimize flooding and state — flooding link-state info toward the spine, summarizing toward the leaves. (Mechanism stated from general draft framing; treat specifics as unconfirmed pending the draft.)
- Where applicable: Clos/fat-tree datacenter fabrics specifically — by construction it's not a general-purpose IGP. Worth a look as a contrast to the "BGP everywhere in the DC" orthodoxy (cf.
draft-ietf-rtgwg-bgp-routing-large-dc).