240 ITU‐T's Technical Reports and Specifications Figure 25 – Sensing and Network Layer Source: Ministry of Transportation and Communications of Peru MPLS and Ethernet as Access Networks These types of networks are used mainly as part of the transport facilities inside telecommunication networks; but also can be used as access networks specifically in business environments for the connectivity for example of branch offices. FTTX Access Networks Fiber to the X (FTTX) is a generic term for any broadband network architecture using optical fiber to provide all or part of the local loop used for last mile telecommunications. The term is a generalization for several configurations of fiber deployment, ranging from FTTN (fiber to the neighborhood) to FTTD (fiber to the desktop). One of the most used technologies for FTTX is the passive optical network (PON). It is a point‐to‐multipoint fiber to the premises network architecture in which unpowered optical splitters utilizing Brewster's angle principles are used to enable a single optical fiber to serve multiple premises, typically 32 to 128. A PON consists of an optical line terminal (OLT) at the service provider's central office (CO) and a number of optical network units (ONUs) near end users. A PON configuration reduces the amount of fiber and CO equipment required compared with point to point architectures. The telecommunications industry differentiates between several distinct FTTX configurations. The terms in most widespread use today are: 1. FTTN / FTTLA (fiber‐to‐the‐node, ‐neighborhood, or ‐last‐amplifier): fiber is terminated in a street cabinet, possibly miles away from the customer premises, with the final connections being copper. FTTN is often an interim step toward full FTTH and is typically used to deliver advanced triple‐play telecommunications services.