Efficient Remote Protection

This document specifies Efficient Remote Protection (ERP), a mechanism for IP Fast Reroute (IP-FRR) that utilizes network notifications to activate pre-computed backup paths at nodes multiple hops upstream of a failure. ERP addresses scenarios where local protection mechanisms, such as Loop-Free Alternates (LFA) or Topology-Independent LFA (TI-LFA), result in suboptimal paths, specifically traffic hairpinning. By activating protection at strategically selected upstream nodes rather than at the node immediately adjacent to the failure, ERP preserves routing optimality and prevents bandwidth waste. ERP applies to both complete link/node failures and performance degradations such as congestion or reduced link capacity. This makes ERP particularly beneficial in networks with high link utilization, such as AI data centers and Data Center Interconnect (DCI) networks.