3Com NBX 100 Administrator's Manual - page 456
456
G
LOSSARY
field is an 8-bit number (0 through 255). IP addresses can be permanently
assigned, or they can be temporarily assigned by
DHCP
.
IP telephony
Technology that allows voice, data, and video to be transmitted over
IP-based networks.
ISDN
Integrated Services Digital Network. An international telecommunications
standard for transmitting voice, video and data over digital lines running
at 64 Kbit/s. ISDN uses B channels, or “bearer” channels, to carry voice
and data. It uses a separate D channel, or “delta,” channel for control
signals to the telephone company computer.
ITU
International Telecommunication Union. An international standards
organization for telecommunications.
J
jitter
The variation in latency (waiting time) for different packets on the
network. For real time data such as voice transmission, jitter must be kept
to a minimum.
K
key mode
A telephone system operating model in which each telephone in the
system has buttons for each available outside line. Also known as a
square plan or a direct system inward access (DISA) system. See also
hybrid mode
.
L
LAN
local area network. A communications system that links computers,
printers, and other devices. LANs allow users to communicate and share
resources like hard disk storage and printers. Devices linked by a LAN may
be on the same floor or within a building or campus.
LAN segment
A section of a local area network that is used by a particular workgroup or
department and separated from the rest of the LAN by a bridge, router or
switch.
LAN switch
A network device that connects stations or LAN segments, also known as
a frame switch.
latency
The sum of all the delays in an end-to-end connection.