Filter
Top Products
65
AXIS 231D+/232D+ - Glossary of Terms
forms part of the Internet Protocol suite, as defined by the
Internet Engineering Task Force. The protocol can support
monitoring of network-attached devices for any conditions
that warrant administrative attention.
Sockets - Sockets are a method for communication between
a clie
nt program and a server program over a network. A
socket is defined as "the endpoint in a connection." Sockets
are created and used with a set of programming requests or
"function calls" sometimes called the sockets application
programming interface (API).
SSL/TSL (Secure Socket Layer/Transport Layer Security)
These two protocols (SSL is succeeded by TSL) are
c
ryptographic protocols that provide secure communication
on a network. SSL is commonly used over HTTP to form
HTTPS, as used e.g. on the Internet for electronic financial
transactions. SSL uses public key certificates to verify the
identity of the server.
Subnet & subnet mask - A subnet is an identifiably
sep
arate part of an organization's network. Typically, a
subnet may represent all the machines at one geographic
location, in one building, or on the same local area network
(LAN). Having an organization's network divided into
subnets allows it to be connected to the Internet with a
single shared network address.
The subnet mask is the part of the IP address that tells a
ne
twork router how to find the subnet that the data packet
should be delivered to. Using a subnet mask saves the router
having to handle the entire 32-bit IP address; it simply looks
at the bits selected by the mask.
Switch - A switch is a network device that connects
ne
twork segments together, and which selects a path for
sending a unit of data to its next destination. In general, a
switch is a simpler and faster mechanism than a router,
which requires knowledge about the network and how to
determine the route. Some switches include the router
function. See also Router.
TCP (Transmission Contr
ol 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
c
onnection 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
an
other 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 vide
o.
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
sin
gle receiver over a network. A new connection is
established for each new user.
UPnP
TM
- A set of computer network protocols that allows
the automatic peer-to-peer detection of devices on the
network. UPnP is promoted by the UPnP Forum.
URL (Uniform Resource Locator) - An "address" on the
network.
USB - (Universal Serial Bus) A plug-and-play interface
betwe
en a computer and peripheral devices, e.g. scanners,
printers.
Varifocal lens - A varifocal lens provides a wide range of
foc
al 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 geogra
phical scale.
W-LAN (Wireless LAN) - A wireless LAN is a wireless local
area netw
ork 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 brow
sers 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