Route distribution between the border and core levels is done using the standard BGP/OSPF deployment practice. Further protection at the switch level can be achieved using the spanning. In this tech paper, you will learn about the key protocols for building a redundant network and discover—based on five examples—how to design highly available three-tier or two-tier networks using LANCOM products. This paper is part of the series “switching solutions“. What method is there? 04-19-2024 02:04 PM 04-19-2024 04:47 AM You need first to use PO for all connection. 04-19-2024 05:51 AM. A Core Switch is a critical device that operates in the backbone portion of a network, primarily used for high-speed data switching. We usually follow this order: Internet > WAN > NAT (Router) > Core Layer Switch > Aggregation.