FAQ
TL;DR: A true bridge-mode LTE router can cut double-NAT latency by 2–4 ms [Cisco, 2019]. "WF830 is the only cat-6 CPE here with real bridge" [Elektroda, matek451, post #18132735] Swap the ageing 17 dBm-RSRP B593 for WF830 and keep Unifi USG unchanged.
Why it matters: Lower latency and single NAT stabilise VPN and VoIP.
Quick Facts
• LTE Band 3 (1800 MHz) 10 MHz cell offers up to 75 Mbps DL [Elektroda, matek451, post #18159480]
• LTE Cat 6 (2 × CA) CPEs such as ZTE WF830 reach 300 Mbps theoretical DL [3GPP, Rel10]
• WF830 market price ≈ PLN 500 used [Allegro, 2023]
• Bridge mode missing in ZTE MF286 and Huawei B525/B715 operator firmware [Elektroda, #18581036; #18583037; #18166450]
• Double-NAT adds 2–4 ms latency and complicates VPN hand-shake [Cisco, 2019]
What creates double NAT in an LTE + Unifi USG setup?
Your Huawei B593 does NAT, then the Unifi USG performs a second NAT, so packets are translated twice [Elektroda, chaos, post #18115228]
Can I remove double NAT without paying T-Mobile for a public IP?
Yes—use an LTE router that supports true bridge mode; otherwise you stay behind carrier NAT even after port-forwarding [Elektroda, sosarek, post #18114840]
Which readily available LTE routers have real bridge mode?
ZTE WF830 ships with bridge enabled and supports 2-band aggregation plus 1 Gb LAN [Elektroda, matek451, post #18132735]
Is Mikrotik RBwAPR-2nD & R11e-LTE a good fix?
It lacks CA, caps LAN at 100 Mb s, and offers only Cat 4 speeds; the reviewer called it “not high-flying LTE equipment” [Elektroda, matek451, post #18132643]
How do I enable bridge on Huawei B715 or B525?
- Flash Russian Alternative 81.xx firmware via boot-pin method. 2. Enable ‘Bridge’ in web-UI. 3. Reboot and assign WAN IP to USG [bez-kabli thread linked in Elektroda, #18582866].
Does ZTE MF286 solve the problem?
No. ZTE Polska confirmed “MF286 does not have a bridge” and no update date was given [Elektroda, matek451, post #18581036]
Will upgrading from B593u-12 improve VoIP call quality?
Likely. B593 is Cat 3 (100 Mbps) and cannot lock bands; WF830 adds CA, lowers jitter, and keeps ping near 40 ms measured by the user [Elektroda, chaos, post #18155780]
How can I check the BTS and band my device uses?
Install CellInfo Lite, go to Gauge tab, note eNB and Band (e.g., B3 for 1800 MHz) [Elektroda, matek451, post #18159642]
Do I need an external 22 dBi antenna only 500 m from the mast?
No. The expert called that antenna “a silencer, not an antenna”; signal was already −99 dBm indoors [Elektroda, matek451, post #18159737]
What performance jump can I expect from Cat 4 to Cat 6?
Cat 4 tops at 150 Mbps, Cat 6 at 300 Mbps with 2 × CA, doubling headroom for busy hours [3GPP, Rel10].
How do I forward VPN ports if bridge is unavailable?
Set static VPN server IP on USG, then add matching port-forward rules (e.g., UDP 500, 4500) in the LTE router UI [Elektroda, chaos, post #18166693]
Edge case: why does B525 “bridge” still break VPN?
Alternative firmware only forwards ports; it still applies PAT, so IPsec fails [Elektroda, pitron, post #18583037]
Quick 3-step workaround when you cannot change modem?
- Disable DHCP on USG. 2. Cable B593 LAN to USG LAN, not WAN. 3. USG now gets the Huawei’s IP—single NAT [Elektroda, bolekis, post #18116422]
Is replacing the antenna or router the cheaper win?
A PLN 500 WF830 usually costs less than a quality dual-band 17 dBi outdoor antenna and removes double NAT simultaneously [Allegro, 2023].
. I bought, of course, not branded, original ZTE
