7 Appendix A: Glossary
ARP: Address Resolution Protocol. A protocol used to "resolve" IP addresses into underlying Ethernet MAC addresses.
ATSC: Advanced Television Systems Committee. An American organisation working with standardisation of digital television broadcasts, primarily in the US but also in Asia and other parts of the world.
DiffServ: Differentiated Services. A mechanism used on layer 3 - e.g. the IP layer - to differentiate between traffic of various types. DiffServ is based on the ToS field and provides a mechanism for the network to give e.g. video traffic higher priority than other traffic (for example Internet traffic).
DVB: Digital Video Broadcasting. The European consortium defining standards for transmission of digital TV broadcasts, primarily in Europe.
DVB ASI: Digital Video Broadcasting Asynchronous Serial Interface. A common physical interface for transmission of MPEG2 Transport Streams (i.e.
DWDM: Dense Wavelength Division Multiplexing. A mechanism to utilize existing fiber with even more bandwidth by adding extra signals using other wavelengths/colors.
Ethernet: Originally a 10Mbit/s shared medium network type developed by Xerox. Later transformed into an official standard. Nowadays, most Ethernet networks are based on full duplex connections over twisted pair cables. Ethernet switches in the network take care of routing Ethernet frames between nodes. The speeds now supported are 10Mbit/s, 100Mbit/s and 1000Mbit/s. 10Gigabit/s Ethernet networks are now emerging.
FEC: Forward Error Correction. A mechanism to add extra data to a transmission in order to protect it. Dependent on the amount of extra data added, the receiver will be able to correct errors (i.e. regenerate lost packets) in case of network packet loss.
HDTV: High Definition Television. The new, coming television standard(s) that gives clearer and more detailed TV pictures. Many TV sets sold today (especially
HTTP: HyperText Transfer Protocol. The fundamental protocol used on the Internet for transmission of WEB pages and other data between servers and PCs.
ICMP: Internet Control Message Protocol. ICMP messages, delivered in IP packets, are used for
IGMP: Internet Group Management Protocol. IGMP is a protocol used to manage multicasts on the Internet. For a host (receiver unit) to receive a multicast, it needs to transmit IGMP "join" messages on the right
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