User's Manual

74
Glossary
Gigaset C450 IP / GBR PTT / A31008-M1713-L151-1-7619 / glossary.fm / 15.5.06
Version 4, 16.09.2005
Port Number
Indicates a specific application of a net-
work subscriber. Depending on the
setting in the LAN, the port number is
permanently assigned or else it is
newly assigned with each access.
The combination of IP address/port
number identifies the recipient or
sender of a data packet within a net-
work.
PPPoE
Point-to-Point Protocol over Ethernet
Protocol for connecting network sub-
scribers within an Ethernet network to
the Internet via a modem.
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 the IP
address/domain name 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 or 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. Such items 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
subscriber'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 No Reply).
If a participant does not respond when
called, a caller can arrange an auto-
matic ringback. As soon as the destina-
tion phone has completed a call and is
free again the caller is rung back. This
feature must be supported by the
exchange. The ringback request is
automatically cancelled after about 2
hours (depending on the VoIP pro-
vider).