BGP Deterministic Path Forwarding (DPF)

Modern data center (DC) fabrics typically employ Clos topologies with External BGP (EBGP) for plain IPv4/IPv6 routing. While hop-by-hop EBGP routing is simple and scalable, it provides only a single best- effort forwarding service for all types of traffic. This single best-effort service might be insufficient for increasingly diverse traffic requirements in modern DC environments. For example, loss and latency sensitive AI/ML flows may demand stronger Service Level Agreements (SLA) than general purpose traffic. Duplication schemes which are standardized through protocols such as Parallel Redundancy Protocol (PRP) require disjoint forwarding paths to avoid single points of failure. Congestion avoidance may require more deterministic forwarding behavior. This document introduces BGP Deterministic Path Forwarding (DPF), a mechanism that partitions the physical fabric into multiple logical fabrics. Flows can be mapped to different logical fabrics based on their specific requirements, enabling deterministic forwarding behavior within the data center.