BGP Deterministic Path Forwarding (DPF)#

Kevin Wang, Michal Styszynski, Wen Lin, Mahesh Subramaniam, Thomas Kampa, Diptanshu Singh (Juniper)

• Why: Hop-by-hop EBGP gives every flow one best-effort service; AI/LLM flows, multi-tenant GPU-as-a-service SLAs, and PRP-style replication need path separation that plain IP fabrics don't offer. This is a lightweight traffic-engineering answer for IP fabrics.
• What: Partitions a physical Clos fabric into multiple logical fabrics by "coloring" EBGP sessions and routes. Use cases shown: queue-pair pinning for ROCEv2 (pinning QPs to disjoint paths), per-tenant SLA separation for GPU-as-a-service, and fate-sharing avoidance (exception flows and PRP redundant flows mapped to different logical fabrics).
• How: Each EBGP session carries a color community; a route is only accepted over a session of matching color (uncolored routes match any). A new SESSION-COLOR capability in the BGP OPEN negotiates color, in strict mode (early misconfiguration detection, session flaps on color change) or loose mode (no flap, late detection). Coloring modes: primary-only, primary+backup (AIGP makes backup劣 — backup paths carry AIGP so primary wins), primary+all-backups (the QPP mode), and all-colors ECMP with firewall-filter flow mapping.
• Where applicable: Any EBGP Clos fabric (RFC 7938 style). Individual draft (-00) presented at IDR — early, no adoption signal yet; vendor-driven (Juniper) with concrete switch-level use cases.