WAN Port on Router Explained - What is it and How to use it
Wireless Router] Dual WAN introduction and setup - Failover and Load Balance | Official Support | ASUS Global
Amazon.com: UTT ER840G 4 WAN Ports Internet Router with 4 Gigabit WAN Ports, Wired VPN Router with Load Balance & Failover, IPSec and PPTP VPN, Access Control, for Home and Small Business :
WAN Port on Router Explained - What is it and How to use it