A metropolitan area network (MAN) is usually a backbone that connects LANs to each other and LANs to WANs, the Internet, and telecommunications and cable networks. A majority of today’s MANs are Synchronous Optical Networks (SONETs) or FDDI rings and Metro Ethernet provided by the telecommunications service providers.
SONET is a standard for telecommunications transmissions over fiber-optic cables.
SONET is self-healing, meaning that if a break in the line occurs, it can use a backup redundant ring to ensure transmission continues.
Metro Ethernet
Ethernet LANs can connect to previously mentioned MAN technologies, or they can be extended to cover a metropolitan area, which is called Metro Ethernet.
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