dcast world. Telecom facilities are often called services. For example, it's quite common, but a misuse of the term to say or write T1 Service or DS3 Service when describing or mean- ing a T1 or DS3 access or transport facility. FEC Forward Error Correction is Bits or Bytes of information added to content that can be used to detect and reverse errors caused in the transport process. For example, terrestrial and satellite wireless (radio) transmission is said to rely on 3/4 or 7/8 FEC. Take this to mean that for every 3 units of payload, add 1 unit, or for every 7 units, add 1 unit of specifically coded information to be used to detect and correct errors in transmission. Interface An interface is a connector, or connection point, some- times also called service handoff or service demarcation. Such a desig- nation is most useful when it carries a reference to a single standard such as G.703, RS-232, DVB-ASI, or IEEE 802.11. Internet The Internet is a global network based on a set of proto- cols, depending on units of data encapsulated into packets or protocol data units. Each unit or entity consists of a header followed by a payload. The header contains all the information necessary for routing or moving the payload through the network. IP Internet Protocol Address The IP address is the unique number assigned to a host or other devices in dotted decimal format. It is used to route packets through the network using packet switching techniques. The IP address is functionally similar to telephone numbers used by the PSTN to route phone calls with circuit switching techniques. IP Multicast IP multicast is a routing technique used to route packets from a single source or location to multiple destinations using a common address. Functionally similar to classical bridged networks built on analog and TDM networks and point-to-multi- point ATM networks. GLOSSARY IP Unicast IP unicast is the act of sending IP datagrams, or protocol data units, from one location or address to a single destination or address. Conceptually, IP 