Axis 221 User Manual page 52

Pre/post alarm image - The images from immediately
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before and after an alarm.
Privacy mask - An image or specified area used to block
out certain parts of the video image.
Protocol - A special set of rules governing how two entities
will communicate. Protocols are found at many levels of
communication, and there are hardware protocols and
software protocols.
Router - A device that determines the next network point
to which a packet should be forwarded on its way to its
final destination. A router is often included as part of a
network switch (see below).
RTP- Real-Time Transfer Protocol. A transfer protocol
designed for delivery of live contents, e.g. MPEG-4.
SMTP - A common e-mail protocol.
SNMP - Simple Network Management Protocol. An
application layer protocol that facilitates the exchange of
management information between network devices. It is
part of the Transmission Control Protocol/Internet Protocol
(TCP/IP) protocol suite.
Subnet Mask - An IP address consists of two components:
the network address and the host address. "Subnetting'
enables a network administrator to further divide the host
part of the address into two or more subnets. The subnet
mask identifies the subnet to which an IP address belongs.
Switch - Whilst a simple hub transmits all data to all
devices connected to it, a switch only transmits the data to
the device it is specifically intended for.
TCP/IP - Transmission Control Protocol/Internet Protocol.
A suite of network protocols that determine how data is
transmitted. TCP/IP is used on many networks, including
the Internet. TCP keeps track of the individual packets of
information and IP contains the rules for how the packets
are actually sent and received.
Unicast - Communication that takes place over a network
between a single sender and a single receiver.
TM
UPnP - An "address" on the network. UPnP is an
architecture for pervasive peer-to-peer network
connectivity of intelligent appliances, wireless devices, and
PCs of all form factors.
URL - Uniform Resource Locator. An "address" on the
network.
Varifocal - A varifocal lens provides a wide range of focal
lengths, as opposed to a lens with a fixed focal length,
which only provides one.
WAN - Wide-Area-Network. Similar to a LAN, but on a
larger geographical scale.
Web server - A program on a computer (server) providing
the resources (e.g. web pages) requested by the user (client).
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