Fiber, Cable, and DSL use different modems. Most modern high-speed plans use DOCSIS 3.1 (for cable) or an ONT (for fiber). Speed Tier:
Always check your provider's "Approved Modems" list (e.g., Xfinity , Spectrum). how to buy a router and modem
Match your hardware to your plan. A 1Gbps plan needs a modem with a (like the Motorola MB8611 Go to product viewer dialog for this item. ) to avoid bottlenecks. Fiber, Cable, and DSL use different modems