multiWAN

MultiWAN refers to configurations that allow a network to use more than one wide-area network (WAN) connection to reach the internet or other remote networks. It is commonly implemented with a multi-WAN router or firewall that provides multiple WAN interfaces and built-in policy tools. The main goals are redundancy (failover) and increased bandwidth through load sharing.

Operation and configuration: A multi-WAN device monitors the health and performance of each link and routes traffic according to configured rules. In active-passive setups, a primary link carries traffic and a backup link takes over if the primary fails. In active-active setups, traffic is distributed across links. Traffic distribution can be based on per-flow or per-destination policies, per-user rules, or simple round-robin. Some systems offer SLA-based routing or application-aware decisions.

Approaches and relationships: MultiWAN intersects with SD-WAN and BGP-based multi-homing. In small offices, consumer-grade devices provide basic load balancing and failover. In larger networks, BGP multihoming provides redundancy across ISPs, while SD-WAN optimizes routes across multiple links, including MPLS, broadband, and cellular.

Considerations and limitations: Effective multiWAN requires health checks, monitoring, and careful policy design. Load sharing can add latency or cause packet reordering, and NAT/firewall rules may become complex. Using multiple providers raises risk of DNS and routing leakage if not properly configured.

Use cases: It supports business continuity for small and mid-size organizations, improved outbound bandwidth, and resilience for critical services. Devices and platforms range from enterprise routers and firewalls to consumer-grade routers that support multiple WAN links.