The common cables for Ethernet are coaxial cables, twisted pairs, and optical fibers. The coaxial cable is classified into two types: thin cable and thick cable. The twisted-pair cable is classified into shielded twisted pair cable and unshielded twisted pair cable. The optical fiber is classified into multi-mode and single-mode. Among them, the coaxial cable is used for early Ethernet. The transmission distance of the thick cable can reach 500 meters, and the thin cable can reach 185 meters. However, the use of coaxial cable networks has basically disappeared due to the fact that a single point of failure of the coaxial cable will cause the entire network to collapse and the coaxial cable cannot support high-speed Ethernet.