APS

An automatic service restoration function by which a network senses a circuit or node failure and automatically switches traffic over an alternate path. SDH and SONET specifications require APS in order that the self-healing fiber optic network can recover from a fiber or node failure.The physical topologies specified in SDH/SONET standards are path-switched ring and line-switched ring. See also circuit, line-switched ring, node, path, path-switched ring, SDH, self-healing, SONET, and topology.