Technical Terms
191
Peer-to-Peer
Network principle in which the data exchange
occurs decentrally, directly between the individual
computers. In the VoIP field, this means that the
connection exists directly between the two
subscribers, without server or provider.
POTS
Plain Old Telephony System
This is the classic analog telephone.
Power over
Ethernet
Power over Ethernet is used to identify a property of
devices with Ethernet connection, e.g. IP
telephones. Thus, the power supply is provided via
the Ethernet connection line and not via a power
mains plug, as usual. In this case, the Switch or the
Hub to which this device is connected per Ethernet
must be able to guarantee the power supply via the
Ethernet line.
PSTN
Public Switched Telephone Network
Umbrella term for analog telephone networks,
which usually use digital switches.
QoS
Quality of Service
The quality in communication networks. Depending
on the standard or protocol, different parameters
are used for evaluating the properties, such as loss
rate, availability, transfer rate and delay.
Router
A router connects different kinds of networks to
each other. It recognizes the bordering networks
and neighboring routers and it determines the path
of the data packet. This connection can be created
by using either a software or a hardware solution.
RSVP
Resource Reservation Protocol
IETF standard to guarantee a certain transmission
qualities, such as bandwidth and priority via TCP/IP.
Servers
The workstation computers are connected (e.g. via
Ethernet) to the server, which is the “central
computer”.
Term
Explanation
SIP
Session Initiation Protocol
A network protocol which establishes a communica-
tion session between two or more subscribers.
Smartphone
A smartphone unites the functional scope of a
mobile phone with that of a PDA. You can use a full
keypad or touch screen and speak from a PDA
phone. Digital cameras are sometimes also incorpo-
rated, as in many mobile phones.
SNMP
Simple Network Management Protocol
Network protocol developed by the IETF - an open
international voluntary association of network
engineers, manufacturers and users, which is
responsible for proposals for Internet standardiza-
tion -, to enable network elements (e.g. routers,
servers, switches, printers, computers etc.) to be
monitored and controlled from a central station.
SNTP
Simple Network Time Protocol
Standard for synchronizing clocks in computer
systems over packet-based communication
networks. Although mostly handled via UDP, can
also be transported using other layer 4 protocols
such as TCP. Specifically developed to enable relia-
ble timing over networks with variable packet
propagation time (ping).
Voice
Compression
The voice data are compressed and sent via the
network. This reduces the amount of data to be
transmitted. This is especially important for the
Home Office connection and the coupling of
several branch offices via the Internet.
STUN
STUN is a simple network protocol that recognizes
the existence and type of firewalls and NAT routers
and uses this information to bypass them.
Term
Explanation
