signals from the customers avoid colliding at the intersection because the powered equipment there provides buffering. Active Ethernet (a type of ethernet in the first mile) is a common AON, which uses optical ethernet switches to distribute the signal, incorporating the customers' premises and the central office into a large switched ethernet network. Such networks are identical to ethernet computer networks used in businesses and academic institutions, except that their purpose is to connect homes and buildings to a central office rather than to connect computers and printers within a location. Each switching cabinet can handle up to 1,000 customers, although 400–500 is more typical. This neighborhood equipment performs layer 2 switching or layer 3 switching and routing, offloading full layer 3 routing to the carrier's central office. The IEEE 802.3ah standard enables service providers to deliver up to 1000 Mbit/s, full-duplex, over one single-mode optical fiber FTTP, depending on the provider. Passive optical network A passive optical network (PON) is a point-to-multipoint FTTP network architecture in which unpowered optical splitters are used to enable a single optical fiber to serve up to 128 customers. A PON reduces the fiber and central office equipment required compared with point-to-point architecture. The downstream signal coming from the central office is broadcast to each customer premises sharing a fiber. Encryption is used to prevent eavesdropping. Upstream signals are combined using a multiple-access protocol, usually time-division multiple access (TDMA). Ethernet point-to-point Point-to-Point Protocol over Ethernet (PPPoE) is a common way of delivering triple- and quad-play (voice, video, data, and mobile) services over both fiber and hybrid fiber-coaxial (HFC) networks. Active PPPoE uses dedicated fiber from an operator's central office all the way to the subscribers' homes, while hybrid networks (often FTTN) use it to transport data via fiber to an intermediate point to ensure sufficiently high throughput speeds over last-mile copper connections. This approach has become increasingly popular in recent years with telecoms service providers in both North America (AT&T, Telus, for example) and Europe's Fastweb, Telecom Italia, Telekom Austria and Deutsche Telekom, for example. Google has also looked into this approach, amongst others, as a way to deliver multiple services over open-access networks in the United States. Electrical network Once on private property, the signal is typically converted into an electrical format. The optical network terminal (ONT, an ITU-T term) or unit (ONU, an identical IEEE term) converts the optical signal into an