What function does a fusion router provide in an SD-Access solution?

A fusion router in an SD-Access solution is responsible for route leaking, which is the process of exchanging routing information between user-defined virtual networks (VNIs) and shared services (e.g., data centers, internet access). This allows endpoints within different virtual networks to access common resources. It does not act as a DNS server; that's a separate infrastructure service. While it might contribute to overall forwarding, its primary role isn't just "additional forwarding capacity." Connectivity to external networks is typically handled by a border node, not a fusion router.