5G Home Internet Gateways: Can They Replace Cable?

Fixed wireless 5G home internet has emerged as a legitimate competitor to cable broadband in many US markets. T-Mobile Home Internet and Verizon 5G Home promise speeds rivaling or exceeding cable connections, often at lower prices and with no data caps. But the gateway devices themselves and their networking capabilities deserve closer scrutiny.

Understanding the Hardware

Unlike a cable modem that you can buy off the shelf, 5G home internet gateways are provided by the carrier — usually at no upfront cost as part of the service. T-Mobile's current gateway is the Sagemcom Fast 5688W, while Verizon uses their proprietary 5G Home Router. Both devices combine a 5G modem, Wi-Fi router, and 2-port Ethernet switch into a single unit.

These gateways receive 5G signals from nearby cell towers using internal or external antennas and convert them to a standard home network connection. Placement matters enormously — even a few feet can make a significant difference in signal strength and speed, particularly for millimeter wave (mmWave) connections.

Networking Limitations

Here's where things get interesting for networking enthusiasts. 5G gateways have notable limitations compared to traditional broadband:

• CGNAT — Most 5G home internet uses Carrier-Grade NAT, meaning you don't get a public IP address. This breaks port forwarding, self-hosting, and some VPN configurations
• Limited ports — Typically just one or two Ethernet ports on the gateway itself
• No bridge mode — You generally can't disable the gateway's router function and use your own router in its place
• Double NAT — Connecting your own router creates a double NAT situation that can cause issues with gaming, VoIP, and peer-to-peer applications

Working Around the Limitations

Despite these constraints, you can build a functional home network on 5G internet. Connect your own router to the gateway's Ethernet port and let it handle DHCP and Wi-Fi for your devices. The double NAT is manageable for most users — web browsing, streaming, and most applications work fine. For gaming, enable UPnP on both the gateway and your router.

Some users have had success getting T-Mobile to provide an IPv6 prefix, which effectively bypasses the CGNAT issue for devices that support IPv6. This varies by market and isn't guaranteed.

Performance Reality

Real-world speeds on 5G home internet typically range from 30 to 300 Mbps, depending on your distance from the tower, congestion, and whether you're on sub-6 GHz or mmWave spectrum. Latency is higher than cable — usually 20 to 50 ms versus 5 to 15 ms for cable. For most households, these numbers are perfectly adequate. For competitive online gaming or latency-sensitive work applications, cable or fiber remains the better choice.

5G home internet works best as a primary connection in areas underserved by cable, or as a secondary/backup connection for redundancy. It's a viable alternative, not yet a universal replacement.