An architect is designing a connectivity solution for a customer.

Dual multihomed is the only listed WAN design that satisfies all failure conditions: CE, PE, ISP, and link failure. A single-homed design has one provider attachment and cannot survive most of those events. A single multihomed design uses more than one provider or provider connection, but if it still has only one customer edge device, a CE failure remains a single point of failure. A dual-homed design can provide multiple links to one provider, but it may not protect against a complete ISP failure. Dual multihoming combines redundant customer edge devices with connections to multiple provider edge devices and, typically, multiple providers. Cisco WAN and BGP design guidance uses multihoming to increase availability, control inbound and outbound path selection, and avoid dependence on a single provider path. This design gives the architect the necessary device, link, and provider diversity. Reference topics: WAN edge redundancy, BGP multihoming, dual-provider design, CE and PE resiliency, internet edge high availability.