ISP network topology implementing three-tier architecture with BGP routing at core, CGNAT load balancing, and PPPoE access. Huawei NE8000 BGP router peers with Internet and feeds Distribution Switch, which branches to dual MikroTik CCR routers for CGNAT client aggregation and Huawei NE8000 BNG for PPPoE subscriber termination. This design separates routing, address translation, and access functions across dedicated layers, enabling carrier-grade redundancy and subscriber scaling. Fork this diagram on Diagrams.so to customize IP addressing, add failover links, or model your own ISP access network. The dual-CGNAT architecture demonstrates load distribution best practices for high-volume residential broadband deployments.