Siemens Gigaset C450IP Owner's Manual page 95

Glossary
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.
Subnet mask
IP addresses consist of a fixed network
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. For the subnet mask
255.255.255.0, for example, the first
three parts of the IP address are the net-
work number and the last part the sub-
scriber 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.
T
TCP
Transmission Control Protocol
Transport Protocol. Session-based
transmission protocol: it sets up, moni-
tors and terminates a connection
between sender and recipient for trans-
porting data.
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TLS
Transport Layer Security
Protocol for encrypting data transmis-
sions on the Internet. TLS is a superor-
dinated Transport Protocol.
Toggling
Toggling allows you to switch between
two callers or between a conference
call and an individual caller without
allowing the waiting caller to listen in.
Transmission rate
Speed at which data is transmitted in
the WAN or LAN. The transmission rate
is measured in data units per unit of
time (Mbit/s).
Transport Protocol
Controls data transport between com-
munication partners (applications).
See also: UDP, TCP, TLS.
U
UDP
User Datagram Protocol
Transport Protocol. Unlike TCP, UDP is
a non session-based protocol. It does
not establish a fixed connection. The
data packets (datagrams) are sent as
Broadcast. The recipient is solely
responsible for making sure the data is
received. The sender is not notified
about whether it is received.
URI
Uniform Resource Identifier
Character string used to identify
resources (e.g. Email recipient, http://
siemens.com, files).
On the Internet URIs are used as a
unique identification for resources.
URIs are also described as an SIP
address.
URIs can be entered in the phone as a
number. By dialling a URI you can call
an Internet subscriber with VoIP equip-
ment.