Zhongguancun Laboratory Tsinghua University CZ.NIC Tsinghua University USA National Institute of Standards and Technology Huawei This document describes AS_PATH verification based on Autonomous System Provider Authorization (ASPA) for egress eBGP speakers. ASPA is a Resource Public Key Infrastructure (RPKI) object that allows an AS to register its transit provider ASes. Performing ASPA-based AS_PATH verification at egress can prevent inadvertent propagation of route leaks to external peers, check for local misconfigurations, and help detect potential ASPA registration errors. This approach complements ingress-side verification and BGP Roles/Only to Customer (OTC); it also provides operational assurance for partial deployment and for export-side configuration or registration problems.