aves, PRACTICAL IP AND TELECOM FOR BROADCAST ENGINEERING AND OPERATIONS waveguide, and fiber. Magnetic and optical storage enable physical transport as an alternative or in addition to network or electronic transport. Multi-Media Multi-media (also spelled multimedia) is a truncation of the word multiple, appended to the plural of medium, media. Meaning different things to different people, its use herein is avoided in an attempt to reduce confusion. Network A network is a collection of equipment, software, and systems connected together physically and configured to provide services. Networks are generally thought of in the context of their geographical or physical coverage. Networks may provide one- or two-way services with symmetrical or asymmetrical bandwidth and multiple classes of service. The term, as used in this book, includes electronic communications facilities and specifically ex- cludes physical transportation facilities. Content on media can be read from the media and placed on a network for transport in real time or as a file transfer. Networks are implemented with different conceptual approaches, standards, and technologies. NID A Network Interface Device is typically a piece of equipment with standard television and network interfaces on the customer side and network interfaces on the network side. It performs the function of mapping the digital television payload to the network channel and may also be used to aggregate voice and data traffic into and out of the network. Port Port is one of those widely used terms meaning the input, output, or both of equipment, network node, or software applica- tion. POTS Plain Old Telephone Service PCR Program Clock Reference (MPEG Jargon) Primary Clock Reference (Telco Lingo) Peak Cell Rate (ATM Speak) Private Line A privacy line is typically a point-to-point circuit or facility provisioned by a common carrier or service provider accord- ing to a formal tariff or on an individual-case basis with specific amount of bandwidth and capabilities not shared with othe