Axis Communications 1011W Manuale Utente

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AXIS M1011/M1011-W/M1031-W - Glossary of Terms
video bridges as well as multicast-to-unicast translators.
RTCP offers quality-of-service feedback from receivers to 
the multicast group as well as support for the 
synchronization of different media streams. 
RTP (Real-Time Transport Protocol) - RTP is an Internet 
protocol for the transport of real-time data, e.g. audio and 
video. It can be used for media-on-demand as well as 
interactive services such as Internet telephony. 
RTSP (Real Time Streaming Protocol) - RTSP is a control 
protocol, and a starting point for negotiating transports 
such as RTP, multicast and Unicast, and for negotiating 
codecs. 
RTSP can be considered a ‘remote control’ for controlling 
the media stream delivered by a media server. RTSP servers 
typically use RTP as the protocol for the actual transport of 
audio/video data.
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 creates and/or maintains a 
special routing table that stores information on how best to 
reach certain destinations. A router is sometimes included 
as part of a network switch. See also switch.
Server - In general, a server is a computer program that 
provides services to other computer programs in the same 
or other computers. A computer running a server program 
is also frequently referred to as a server. In practice, the 
server may contain any number of server and client 
programs. A web server is the computer program that 
supplies the requested HTML pages or files to the client 
(browser). 
Sharpness - This is the control of fine detail within a 
picture. This feature was originally introduced into color 
TV sets that used notch filter decoders. This filter took 
away all high frequency detail in the black and white 
region of the picture. The sharpness control attempted to 
put some of that detail back in the picture. Sharpness 
controls are mostly superfluous in today's high-end TVs. 
The only logical requirement for it nowadays is on a VHS 
machine. 
Simplex - In Simplex operation, a network cable or 
communications channel can only send information in one 
direction.
SMTP (Simple Mail Transfer Protocol) - SMTP is used for 
sending and receiving e-mail. However, as it is ‘simple,’ it 
is limited in its ability to queue messages at the receiving 
end, and is usually used with one of two other protocols, 
POP3 or IMAP. These other protocols allow the user to save 
messages in a server mailbox and download them 
periodically from the server. 
SMTP authentication is an extension of SMTP, whereby 
the client is required to log into the mail server before or 
during the sending of email. It can be used to allow 
legitimate users to send email while denying the service to 
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.
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