Axis CAMERA STATION User Manual page 37

unauthorized users, such as spammers.
SNMP (Simple Network Management Protocol) - SNMP 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 client 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 cryptographic 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 separate 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 network 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 network 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 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.
AXIS Camera Station - Glossary of Terms
37
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.