Cisco end-to-end enterprise network solutions form the most comprehensive line of networking products available in the industry. From the branch office to the WAN and campus backbone, Cisco products are the leading choice of the enterprise. The interface processors implement the network interfaces making it possible to support the most heavily used network interfaces.The Packet-Over-SONET specification for optical-fiber transmission defines two types of fiber: single mode and multimode. Modes can be thought of as bundles of light rays entering the fiber at a particular angle. Single-mode fiber allows only one mode of light to propagate through the fiber, while multimode fiber allows multiple modes of light to propagate through the fiber. Multiple modes of light propagating through the fiber travel different distances depending on the entry angles, which causes them to arrive at the destination at different times (a phenomenon called modal dispersion); therefore, single-mode fiber is capable of higher bandwidth and greater cable run distances than multimode fiber.