Nomadix AG 5500, User Manual, Page: 331 / 338

AG 5500
Glossary of Terms 319
Tunneling
A technology that enables one network to send its data via another network's connections. Tunneling works by
encapsulating a network protocol within packets carried by the second network. For example, Microsoft's PPTP
technology enables organizations to use the Internet to transmit data across a Virtual Private Network (VPN). It does
this by embedding its own network protocol within the TCP/IP packets carried by the Internet. See also,
TCP/IP
and
VPN .
ToS
(Type of Service) A field within an IP header which can be used by the device originating the packet, or by an
intermediate networking device, to signal a request for a specific QoS level. ToS uses three bits to tell a router how to
prioritize a packet and one bit apiece to signal requirements for delay, throughput, and reliability. See also,
Packet
,
QoS , Router , and Throughput .
URL
(Uniform Resource Locator) The standard method used for identifying the location of information available to the
Internet. This is effectively the “address” of a document or file, expressed in the form:
protocol://domain.filename/
path.type (for example, http://www.myfile.com/nextpage.html ).
UTC
(Coordinated Universal Time) A time scale that couples Greenwich Mean Time (GMT), which is based solely on the
Earth's inconsistent rotation rate, with highly accurate atomic time. When atomic time and Earth time approach a one
second difference, a leap second is calculated into UTC. UTC was devised on January 1, 1972 and is coordinated in
Paris by the International Bureau of Weights and Measures. UTC, like GMT, is set at 0 degrees longitude on the prime
meridian
VoIP
(Voice over IP) An emerging technology for transporting integrated digital voice, video, and data over IP networks. A
major advantage of VoIP and Internet telephony is that it avoids the tolls charged by ordinary telephone services. See
also,
Internet
and
IP
.
VPN
(Virtual Private Network) A network that is constructed by using public wires to connect nodes. For example, there are
a number of systems that enable you to create networks using the Internet as the medium for transporting data. These
systems use encryption and other security mechanisms to ensure that only authorized users can access the network and
that the data cannot be intercepted.
VxWorks ®
A real-time operating system, manufactured and sold by Wind River Systems of California, USA. VxWorks program
development requires a host machine running Unix or Windows.
W3C
(World Wide Web Consortium) An international consortium of companies involved with the Internet and the Web. The
organization's purpose is to develop open standards so that the Web evolves in a single direction rather than being
splintered among competing factions. The W3C is the chief standards body for HTTP and HTML. See also,
HTML
and HTTP .
WAN
(Wide Area Network) Take two local area networks, hook them together, and you've got a WAN. Wide area networks
can be made up of interconnected smaller networks spread throughout a building, a state, a country, or the entire globe.
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