Failover vs load balancing
Failover keeps one line as primary and switches everything to the second line only when the first one fails, then switches back when it recovers. It is simple and predictable, and is the right choice when the second line is a slower or metered backup, such as a 4G/5G router.
Load balancing uses both lines at the same time, spreading connections between them, and still fails over if one goes down. You get more total capacity for many users, which helps in hotels and offices.
One thing load balancing does not do: it does not make a single download or video call faster than one line. Each connection uses one line; the gain comes from many users and many connections being spread across both.
Picking the two lines
- Use two different providers. Two connections from the same ISP often fail together.
- Prefer different physical paths: two fibre lines entering from different sides, or fibre plus a wireless or 4G/5G backup.
- Ask both ISPs to put their router or ONT in bridge mode where possible, or at least note their LAN IP ranges so they do not clash with yours.
- If you need VPN access from outside (for CCTV or remote staff), ask for a static IP on at least one line.
Routers that handle two or more lines
| Model | Type | Notable for |
|---|---|---|
| TP-Link Omada ER605 | Multi-WAN VPN router | Up to 4 WAN, load balancing, VPN; easy Omada management |
| TP-Link Omada ER7206 | Multi-WAN VPN firewall router | SPI firewall, up to 4 WAN, site-to-site VPN |
| Grandstream GWN7002 / GWN7003 | Multi-WAN VPN router | Also manages up to 100 / 150 Grandstream access points; 2 PoE-out ports |
| MikroTik hEX, L009, RB5009 | RouterOS router | Any port can be a WAN; fine control over balancing, failover checks and hotspot |
| UniFi Cloud Gateway Ultra / Dream Machine Pro | Security gateway | Multi-WAN failover plus the UniFi controller built in |
Product pages with current prices: ER605, ER7206, GWN7002, GWN7003, hEX, L009, RB5009, Cloud Gateway Ultra, Dream Machine Pro.
Which one for your site
- Small office, shop or clinic, no IT staff: Omada ER605, or a UniFi Cloud Gateway Ultra if you are already on UniFi.
- Growing office with branches or remote staff: Omada ER7206 for site-to-site VPN, or a UniFi gateway.
- Hotel or office on Grandstream access points: GWN7002 or GWN7003, since the same box manages the access points.
- Hotel with a guest login page, many users, or more than two lines: MikroTik (L009 for small hotels, RB5009 for larger ones). See which MikroTik router.
Details that decide whether it works
Most failover problems are not the router failing; they are the router not noticing. An ISP line can stay 'up' on the cable while the internet behind it is dead. A good setup checks real reachability (pinging a public address through each line) rather than only the link light. MikroTik calls this recursive routing or netwatch; Omada, Grandstream and UniFi have their own online detection settings.
Some websites, especially banking and government portals, do not like a session that jumps between two public IP addresses. Routers solve this by keeping each connection on one line (MikroTik's PCC, or 'sticky' sessions on other brands). If staff complain that a portal logs them out, this is the first thing to check.
On a hotel hotspot, balancing also has to keep each guest's login on one line. That is part of what we configure in our managed firewall and MikroTik setup services.
Questions
+Will two 100 Mbps lines give me 200 Mbps?
In total across many users, roughly yes. For a single download or speed test, no: one connection uses one line.
+Can I use a 4G/5G router as a backup line?
Yes. Connect the 4G/5G router's LAN port to a WAN port on the multi-WAN router and set it as the failover line.
+Do I need a firewall as well as a dual WAN router?
The routers listed here include a firewall. A separate gateway such as the ER7206 or a UniFi gateway adds stronger VPN and network separation features in one box.
+Can you set up load balancing on our existing MikroTik?
Yes, on site or remotely. WhatsApp us the model and your two ISPs.
Prices change often, so this guide does not quote them. Each product page shows the current price including GST. Specifications are from the manufacturers' listings; check the product page or datasheet before you order.