GoKawiilExplainer: Why cable internet upload speeds lag behind download speeds
Cable internet relies on coaxial lines originally built for one-way cable TV broadcasts, so providers allocate most available bandwidth to downloads rather than splitting it evenly with uploads. The DOCSIS standard lets internet signals run over these legacy cables, but upgrading equipment to boost upload capacity is costly for ISPs. Fiber internet avoids this tradeoff entirely, using light signals with vastly more bandwidth, allowing equal upload and download speeds without the congestion or interference issues that affect shared copper cable networks.