 Time Warner Cable, with cable fran- Requirements published in a Bellcore (now chises in many cities. Telcordia) technical reference for products placed in a central office environment. Bell- MTA (Major Trading Area) core is the former Bell Telephone central A region that includes multiple cities or research organization. There are eight stan- states. They are made up of some of the 491 dards referring to issues such as environmen- BTAs. The FCC auctions off spectrum in tal, electrical, and cabling requirements, as both BTAs and MTAs. well as resistance to natural disasters such as MTSO (Mobile Telephone Switching earthquakes. Office) A central office used in mobile networks. network They connect cellular network calls to the An arrangement of devices that can commu- PSTNs, and vice versa. nicate with one another. An example of a net- work is the PSTN over which residential and multicasting commercial telephones and modems commu- The transmission of the same message from a nicate with one another. single point to multiple nodes. NAS (Network-Attached Storage) multiplexing (muxing) The use of servers for storing files that can A technique in which multiple devices can be accessed directly by computers located on share a circuit. With multiplexing, carriers the LAN. NAS is less costly than traditional do not have to lay cabling for each computer SANs. that communicates. T1 multiplexers and fiber multiplexers enable many devices to nonblocking share strands of fiber, air waves, and copper Switches that have enough capability for cabling. each connected device to communicate at the same time up to the full speed of the port to MVNOs (Mobile Virtual Network which it is connected. Operators) MVNOs such as Tracfone and cable TV number pooling operators resell cellular service on cellular carriers' networks. Allows local carriers to share a "pool" of tele- phone numbers within the same exchange. NAT (Network Address Translation) Number pooling is a way to allocate scarce Translates external IP addresses to internal IP te