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Glossary
VoIP
abbreviation for Voice over IP, also known as Internet tele-
phony
Voice over IP makes telephone calls possible via the Inter-
net. The technology has already been in use for years, but
today it allows even private customers the convenience fa-
miliar from conventional telephony, usually at significant-
ly lower prices. VoIP has also made it considerably more
convenient to use applications like conference calls and
answering machines in networks. Added to this are global
accessibility under a single telephone number and new
VoIP features like the Buddy List known from chat rooms.
Internet telephony used to be possible only with a head-
set connected to the computers of the callers and their
conversation partners. Today voice connections via the In-
ternet, even to fixed-line and mobile networks, can be
conducted conveniently using VoIP telephone systems
that allow already existing analog telephones to be used
even when the computer is switched off. Various Internet
Service Providers and telephony carriers provide SIP fixed-
line gateways for this purpose. Such a gateway is used to
provide voice connections between the Internet and con-
ventional telephone networks. In principle VoIP conversa-
tions are possible via every DSL access point, but for
convenient use with existing terminal devices, and for
conversations with the fixed-line and mobile networks, it
is important that the DSL provider support what is known
as the SIP standard. SIP is the current standard defined for
VoIP by the IETF (Internet Engineering Task Force).
WLAN
abbreviation for Wireless Local Area Network
The term WLAN designates the industry standard for wire-
less local networks passed by the Institute of Electrical
and Electronics Engineers (IEEE) in 1997 under the title
IEEE 802.11.
By means of WLAN technology, individual computers or
network devices like printers or DSL access points can be
linked wirelessly to an existing cable-connected local net-
work (LAN), or LANs can be converted completely to a
