Tsinghua University Tsinghua University Tsinghua University Tsinghua University ByteDance Inc. This document presents use cases and the routing requirements they imply for operating the BGP Link State (BGP-LS) Shortest Path First (SPF) routing developed in the Link-State Vector Routing (LSVR) Working Group, across multiple administrative domains and over hybrid overlay/underlay topologies. After motivating the work, it describes three scenarios of increasing complexity: a single overlay domain, the interconnection of multiple overlay domains, and hybrid overlay/ underlay networks. Each scenario gives the topology, its distinguishing challenges, and the requirements that follow. The scenarios arise in globally distributed edge- and cloud-Point-of- Presence (PoP) deployments that serve performance-sensitive applications such as cross-region real-time communication, collaborative productivity, cloud gaming, and large-scale SaaS.