Three backup options compared
Costs for a second ISP or fixed wireless line vary by address, so the table shows what to compare instead of prices we could not verify.
| Option | Setup on a GL.iNet router | Main limit | Fits |
|---|---|---|---|
| Phone USB tethering | Plug the phone into the USB port; INTERNET, then Tethering [1] | Hotspot data allowance and carrier tethering rules [1][2] | Rare, short outages |
| Second wired ISP | Second Ethernet WAN on models with dual Ethernet WAN [3] | A second monthly bill; the same street cabling may fail too | Frequent or long outages, heavy upload |
| Fixed wireless or 5G home internet | Its gateway plugs into an Ethernet WAN like a second ISP [3] | Plan terms and signal at your address | No second wired provider, or you want a different path |
| Wi-Fi repeater | Repeater interface to a neighbor's or shared network [3] | Only with permission, and their network may be down too | Shared buildings with an agreed backup |
How GL.iNet Multi-WAN failover works
Multi-WAN is under NETWORK, then Multi-WAN. It can use Ethernet (up to two ports on dual-Ethernet-WAN models), Repeater, Tethering and Cellular interfaces. Failover is the default mode: one link is active and the router switches when it fails. You set a priority for each interface, and the router returns to the preferred link automatically when it recovers. [3]
Online detection uses ping to a tracking IP by default. Detection Mode can be Normal (checks continuously), Low Data (checks only when an interface network error occurs, to save data on limited plans) or Strict. Sensitivity Options (firmware 4.5 and later) trade faster switching against false switches on unstable links. Load Balance mode is separate and approximate. GL.iNet notes that live connections are not guaranteed to match the ratio. [3]
On Flint 2, the datasheet lists a USB 3.0 port and an Ethernet port that can switch between WAN and LAN. So a phone, a second ISP, or both can be attached. [4]
Phone tethering: data caps decide how long it lasts
GL.iNet supports USB tethering from both iPhone and Android. On an iPhone you tap Trust, turn on Allow Others to Join in Personal Hotspot, then connect from the router. GL.iNet notes some carriers restrict tethering or charge extra. [1]
Hotspot data is usually limited separately from phone data. As one example, Verizon's unlimited plans page, checked 30 Oct 2026, lists 10 GB of mobile hotspot data on the Simplicity Plan. That plan is listed at $30 a month per line after AutoPay and a $15 a month switch discount, plus taxes and fees. The page also lists Unlimited Hotspot for $15 a month per line plus taxes and fees, with speeds reduced to up to 4 Mbps after 200 GB in a billing cycle. Read your own carrier's plan terms for the allowance and the speed after it runs out. [2]
To size the cap, measure. Reset your phone's hotspot data counter, tether for one typical work hour including a call, and read the counter. Divide your allowance by that number to get the hours of outage the plan can cover.
Worked example: is a backup line worth paying for?
All numbers here are fictional assumptions. Replace them with your own.
| Input | Assumed value | Result |
|---|---|---|
| Value of one lost work hour | $50 | |
| Outage hours in a year on the main line | 12 | 12 x $50 = $600 a year at risk |
| Phone hotspot already in plan | $0 extra | Covers outages if your measured use fits the allowance |
| Hotspot add-on (if your cap is too small) | $15 a month, as on Verizon's page [2] | $180 a year, below the $600 at risk |
| Second wired or fixed wireless line | Your quoted price, say $50 a month | $600 a year, equal to the risk; only worth it if outages are longer or uploads heavier than this |
Settings that avoid surprises
- Put the main line at the highest priority and the phone or second line below it. [3]
- On a metered backup, consider Low Data Mode, which tests only when a network error occurs. GL.iNet says reconnecting after a disconnection may be slightly slower than in Normal mode, so check which mode your tethering interface uses. [3]
- If the router flips back and forth on a flaky main line, lower the sensitivity. [3]
- If you run a VPN on the router, confirm the tunnel reconnects over the backup link.
- Power the modem, router and any backup gateway from a UPS, or a power cut takes the backup down too.
Failover test checklist
- Connect the backup and confirm it shows green on the Multi-WAN page. [3]
- Start a test call or a long download, then unplug the main WAN cable from the modem side.
- Note how many seconds until pages load again, and whether the call recovered or had to be rejoined.
- Check the phone's hotspot counter afterward to confirm data use matches your estimate.
- Plug the main line back in and confirm the router returns to it on its own. [3]
- Repeat every few months and after firmware upgrades, and keep a dated note of the result.
Questions before you decide
Will my video call survive the switch to backup?
Do not assume it will. GL.iNet's Multi-WAN detects failure by tracking and then moves traffic to the next available interface. How fast that happens depends on the detection mode and sensitivity. Test with a real call and treat a dropped and rejoined call as the likely outcome until you see otherwise.
Does my carrier allow tethering to a router?
Check your plan. GL.iNet's tethering guide notes that some carriers restrict tethering or charge extra for it. Verizon's plans page lists a hotspot allowance on its base plan and an Unlimited Hotspot add-on at $15 a month per line, plus taxes and fees.
Sources & verification
Product details and prices can change. Check the linked provider before buying.
- GL.iNet Router Docs 4: Tethering Accessed 30 Oct 2026
- Verizon: Unlimited plans Accessed 30 Oct 2026
- GL.iNet Router Docs 4: Multi-WAN Accessed 30 Oct 2026
- GL.iNet: GL-MT6000 datasheet (ver. 20251103) Accessed 30 Oct 2026
Sources link directly to providers. Product buttons may use separately labeled affiliate links. Read our disclosure.