DOCSIS, a short form for “Data Over Cable Service Interface Specification,” is the technology on which all cable modems are based. DOCSIS 3.0 is the standard currently being used by almost all cable providers, but even though it offers theoretical speeds of up to 1Gbps, most ISPs in the U.S. don’t go beyond 600Mbps over DOCSIS 3.0. You’ll need a DOCSIS 3.1 cable modem to get actual multi-gigabit plans. Don’t worry if your ISP doesn’t support the newer standard yet, though, as all DOCSIS 3.1 modems are fully backward compatible with DOCSIS 3.0, so you can buy one now to be ready when those faster speeds do come along.