are the abstraction of physical hardware addresses just as an internet is an abstraction of physical networks. Actually assigned to the interconnection of a host to a physical network, an IP address consists of a network portion and a host portion. IP backbone A packet-switching network interconnected by routers along with protocols that allow them to function logically as a single, large, virtual network. IP backbones are oper- ated by individual service providers, unlike the Internet, which is composed of more than 10,000 service providers. IP Cablecom The name by which the international community knows PacketCable. See also PacketCable. Glossary IP datagram datagram The basic unit of information passed across a TCP/IP internet. An IP datagram is to an internet as a hardware packet is to a physical network. It contains a source and destina- tion address along with data. IP forwarding The process of forwarding internet packets from one network to another. IP fragmentation A multibridge feature that handles packet size mismatch problems between FDDI and Ethernet endpoints. The maximum FDDI packet size is 4,500 bytes. The maximum Ethernet packet size is 1,548 bytes. Messages that are longer than 1,548 bytes must be fragmented into smaller packets to allow them to enter the Ethernet network. IP long-distance wholesaler A VoIP service provider that offers IP services to domestic and international carriers, corporations, and service providers to carry their traffic, particularly international transit. IP Multicast A protocol for transmitting IP datagrams from one source to many destinations in a LAN or WAN. IP over DWDM The use of IP on an intermediate architecture that runs on a DWDM net- work. Today's networks operate largely with IP running over ATM running over SDH/SONET running over DWDM. IP PBX A new-generation PBX that uses packet-switching technology and offers an attractive platform for the integration of voice and data in the enterprise. IP switch A switch that replaces slower, more processing-intensive rou