Siemens Gigaset S450 IP User Manual page 118

Pre-dialling
See Block dialling.
Private IP Address
See Public IP address.
Protocol
Describes the agreements for commu-
nicating within a Network. It contains
rules for opening, administering and
closing a connection, about data for-
mats, time frames and possible error
handling.
Proxy/Proxy server
Computer program that controls the
exchange of data between Client and
Server in computer networks. If the
phone sends a query to the VoIP server,
the proxy acts as a server towards the
phone and as a client towards the
server. A proxy is addressed via
IP address/Domain namen and Port.
Public IP address
The public IP address is the address for
a network component on the Internet.
It is assigned by the Internet Service
Provider. Devices that act as a link from
a local network to the Internet (gate-
way, router) have a public and a local IP
address.
See also: IP address, NAT
Q
Quality of Service (QoS)
Describes the Quality of Service in com-
munication networks. Differentiations
are made between various Quality of
Service classes.
QoS influences the flow of data packets
on the Internet e.g. by prioritising data
packets, bandwidth reservation and
packet optimisation.
In VoIP networks, QoS influences the
voice quality. If the whole infrastruc-
ture (router, network server etc.) has
QoS, the voice quality is better, i.e.
fewer delays, less echoing, less crack-
ling.
R
RAM
Random Access Memory
Memory in which you have reading and
storage rights. Items such as melodies
and screen pictures are saved in the
RAM after being loaded onto the phone
via the Web configurator.
Registrar
The registrar manages the Network
subscribers's current IP addresses.
When you register with your VoIP pro-
vider, your current IP address is saved
on the registrar. This means you can
also be reached when on the move.
Ringback when the call is not answered
= CCNR (Completion of Calls on No
Reply). If a participant does not
respond when called, a caller can
arrange an automatic ringback. As
soon as the destination phone has
completed a call and is free again the
caller is rung back. This feature must be
supported by the exchange. The ring-
back request is automatically cancelled
after about 2 hours (depending on the
VoIP provider).
Ringback when the number is busy
= CCBS (Completion of Calls to Busy
Subscriber). If a caller hears the busy
tone, he or she can activate the ring-
back function. As soon as the connec-
tion is free the caller is rung back. As
soon as the caller lifts his receiver the
connection is made automatically.
ROM
Read Only Memory
A type of memory that can only be
read, as opposed to RAM which can be
both read and written.
Router
Routes data packets within a network
and between different networks via the
quickest route. Can connect Ethernet
networks and WLAN. Can be a
Gateway to the Internet.
Glossary
117