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AXIS 216FD/FD-V - Glossary of Terms
which requires knowledge about the network and how to
determine the route. Some switches include the router
function. See also
Router
.
TCP (Transmission Control Protocol) -
TCP is used along
with the Internet Protocol (IP) to transmit data as packets
between computers over the network. While IP takes care of
the actual packet delivery, TCP keeps track of the individual
packets that the communication (e.g. requested a web page
file) is divided into, and, when all packets have arrived at
their destination, it reassembles them to re-form the
complete file.
TCP is a connection-oriented protocol, which means that a
connection is established between the two end-points and is
maintained until the data has been successfully exchanged
between the communicating applications.
Telnet -
Telnet is a simple method with which to access
another network device, e.g. a computer. The HTTP protocol
and the FTP protocols allow you to request specific files
from remote computers, but do not allow you logon as a
user of that computer. With Telnet, you log on as a regular
user with whatever privileges you may have been granted
for specific applications and data residing on that computer.
TVL (TV Lines) -
A method of defining resolutions in
analog video.
UDP (User Datagram Protocol) -
UDP is a communications
protocol that offers limited service for exchanging data in a
network that uses the Internet Protocol (IP). UDP is an
alternative to the Transmission Control Protocol (TCP). The
advantage of UDP is that it is not required to deliver all data
and may drop network packets when there is e.g. network
congestion. This is suitable for live video, as there is no
point in re-transmitting old information that will not be
displayed anyway.
Unicast -
Communication between a single sender and a
single receiver over a network. A new connection is
established for each new user.
URL (Uniform Resource Locator) -
An "address" on the
network.
USB -
(Universal Serial Bus) A plug-and-play interface
between a computer and peripheral devices, e.g. scanners,
printers, etc.
Varifocal lens -
A varifocal lens provides a wide range of
focal lengths, as opposed to a lens with a fixed focal length,
which only provides one.
VPN (Virtual Private Network) -
This creates a secure
"tunnel" between the points within the VPN. Only devices
with the correct "key" will be able to work within the VPN.
The VPN network can be within a company LAN (Local Area
Network), but different sites can also be connected over the
Internet in a secure way. One common use for VPN is for
connecting a remote computer to the corporate network, via
e.g. a direct phone line or via the Internet.
VOP (Video Object Plane) -
A VOP is an image frame in an
MPEG-4 video stream. There are several types of VOP:
- An I-VOP is complete image frame.
- A P-VOP codes the differences between images, as long as
it is more efficient to do so. Otherwise it codes the whole
image, which may also be a completely new image.
WAN (Wide-Area-Network) -
Similar to a LAN, but on a
larger geographical scale.
W-LAN (Wireless LAN) -
A wireless LAN is a wireless local
area network that uses radio waves as its carrier: where the
network connections for end-users are wireless. The main
network structure usually uses cables.
Web server -
A Web server is a program, which allows
Web browsers to retrieve files from computers connected to
the Internet. The Web server listens for requests from Web
browsers and upon receiving a request for a file sends it
back to the browser.
The primary function of a Web server is to serve pages to
other remote computers; consequently, it needs to be
installed on a computer that is permanently connected to
the Internet. It also controls access to the server whilst
monitoring and logging server access statistics.
WEP (Wireless Equivalent Privacy) -
A wireless security
protocol, specified in the IEEE 802.11 standard, which is
designed to provide a wireless local area network (WLAN)
with a level of security and privacy comparable to that
usually expected of a wired LAN. Security is at two different
levels; 40-bit and 128-bit encryption. The higher the bit
number, the more secure the encryption.
WINS (Windows Internet Naming Service) -
Part of the
Microsoft Windows NT Server, WINS manages the
association of workstation names and locations with IP
addresses, without the user or administrator having to be
involved in each configuration change.
WPA-PSK (Wi-Fi Protected Access - Pre-Shared Key) -
This wireless encryption method uses a pre-shared key (PSK)
for key management. Keys can usually be entered as manual
hex values, as hexadecimal characters, or as a Passphrase.
WPA-PSK provides a greater degree of security than WEP.
Zoom lens -
A zoom lens can be moved (zoomed) to enlarge
the view of an object to show more detail.
