User's Manual

75
Glossary
Gigaset C450 IP / GBR PTT / A31008-M1713-L151-1-7619 / glossary.fm / 15.5.06
Version 4, 16.09.2005
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 Ether-
net networks and WLAN. Can be the
gateway to the Internet.
Routing
Routing is the transmission of data
packets to another subscriber in your
network. On its way to the recipient,
the data packet is sent from one router
to the next until it reaches its destina-
tion.
If data packets were not forwarded in
this way, a network like the Internet
would not be possible. Routing con-
nects the individual network to this glo-
bal system.
A router is a part of this system; it trans-
mits data packets both within a net-
work and from one network to the
next. Transmission of data from one
network to another is performed on the
basis of a common protocol.
RTP
Realtime Transport Protocol
Global standard for transferring audio
and video data. Often used in conjunc-
tion with UDP. In this case, RTP packets
are embedded in UDP packets.
RTP port
(Local) port by means of which voice
data packets are sent and received for
VoIP.
S
Server
Makes a service available to other net-
work subscribers (clients). The term
can indicate a computer/PC or an appli-
cation. A server is addressed via the IP
address/domain name and port.
SIP (Session Initiation Protocol)
Signalling protocol independent of
voice communication. Used for estab-
lishing and ending a call. It is also pos-
sible to define parameters for voice
transmission.
SIP Address
See URI.
SIP port/Local SIP port
(Local) port by means of which SIP sig-
nalling data is sent and received for
VoIP.
SIP Provider
See VoIP provider.
SIP Proxy Server
IP address of your VoIP provider's gate-
way server.
Static IP address
A static IP address is assigned to a net-
work component manually during net-
work configuration. Unlike a dynamic
IP address, a static IP address never
changes.
STUN (Simple Transversal of UDP over NAT)
NAT control mechanism.
STUN is a data protocol for VoIP tele-
phones. STUN replaces the private IP
address in the data packets of the VoIP
telephone with the public address of
the secure private network. To control
data transfer, a STUN server is also
required on the Internet. STUN cannot
be implemented by symmetric NATs.
See also: ALG, Firewall, NAT, Outbound
Proxy.
Subnet
Segment of a network.