Siemens Gigaset S685 IP User Manual page 169

Glossary
Routing
Routing is the transfer of data packets
to another subscriber in your network.
On their way to the recipient, the data
packets are sent from one router to the
next until they reach their destination.
If data packets were not forwarded in
this way, a network like the Internet
would not be possible. Routing con-
nects the individual networks to this
global system.
A router is a part of this system; it trans-
fers data packets both within a local
network and from one network to the
next. Transfer of data from one net-
work 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 that is used to send and
receive voice data packets for VoIP.
S
Server
Provides a service to other Network
subscribers (Clients). The term can
indicate a computer/PC or an applica-
tion. A server is addressed via IP
address/Domain namen 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 which is used to send and
receive SIP signalling data for VoIP.
SIP provider
See VoIP provider.
168
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 the
Dynamic IP address a static (fixed) 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 with symmetric NATs.
See also: ALG, Firewall, NAT,
Outbound proxy.
Subnet
Segment of a Network.
Subnet mask
IP addresses consist of a fixed line
number and a variable subscriber
number. The network number is identi-
cal for all Network subscribers. The
proportion of the IP address made up of
the network number is determined in
the subnet mask. In the subnet mask
255.255.255.0, for e.g., the first three
parts of the IP address are the network
number and the last part the subscriber
number.
Symmetric NAT
A symmetric NAT assigns different
external IP addresses and port numbers
to the same internal IP addresses and
port numbers – depending on the
external target address.