aware that realization of lower cost is dependent on obtaining use of facilities and services at unit prices based on time used and type of bandwidth occupied for each session or transmis- sion just like the old fashioned long distance telephone call. Standard network performance and characteristics must be under- stood before they can be applied to content transport networks. The next few paragraphs provide an introduction to time division multi- plexing (TDM), ATM, and IP network technology. TDM technology characteristics and performance are the standard cell and packet based network performance should be measured 3 CONTENT TRANSPORT NETWORK DEFINED against. If a standard for TDM is required, then use wire, fiber, or another passive conductor of known performance. The characteristics of interest include available channel bandwidth, bit error rate, and jitter. However, in cell and packet networks, bit errors cause cell and packet loss or impairment, as can jitter. ATM transport technology offers 5 classes of service. Constant bit rate (CBR), variable bit rate-real-time (VBR-rt), variable bitrate- non-real-time (VBR-nrt), unspecified bit rate, and available bit rate. While it may change in the future, ATM CBR is currently the only ATM class of service capable of transporting high-quality, high bit rate content in real time. Packet-switched networks are inherently chaotic unless specifically configured to deal with continuous signal, or mixed-signal traffic and class-of-service. Packet networks are either Ethernet or IP. (Several packet or packet-like techniques exist; however, they only support content transport as a file transfer, not real time.) In general there are two types of IP technology and methodology: Ethernet and Internet. The IEEE 802.1 standard defines Ethernet. Internet or more precisely, IP is defined in RFC 791. Ethernet trans- port of IP is defined in RFC894. Ethernet architecture is built around shared media in the form of common set of cabling where the information is carried in packets, and th