multiSwitch – user manual
© TOPEX 2008 163
E1
– The European format for digital transmissions, equivalent to the T1 format is USA. E1 has a data
rate of 2.048 Mbps, containing 32 channels, each of them having 64 Kbps, and includes two channels
reserved for signaling and control. The US standard, T1, has 24 channels, each having 2.048 Kbps,
and the data rate is 1.544 Mbps. E1 and T1 lines can be interconnected for international usage.
FXS
– Abbreviation for
Foreign Exchange Station
– a phone interface that sends dial tone and
generates call voltage. A standard phone is entered in such an interface to receive telephony services.
An example of a FXS interface is the switch system. FXS can be any device that from the point of view
of a telephone represents a switching system. This system must be capable of offering power voltage
to the connected phone, call signal and dial tone, as well as capable of knowing when the phone is on
or off the hook, when it sends or receives voice messages.
H.323
– an ITU-T recommendation that defines the protocols which sustain the audio-video
communication sessions via any network with packet switching. Currently, this standard is
implemented in several real-time internet applications, such as NetMeeting or Ekiga (the latter uses
the OpenH323 variant).
H.323 is a component of the H.32x protocol series, which provides communications over ISDN, PSTN
or SS7. H.323 is frequently used for Voice over IP (VoIP, internet telephony or IP telephony) and IP-
based videoconferencing.
H.323 was initially created to provide a transport mechanism for multimedia applications in local
networks, but it rapidly evolved to the much bigger requirements of VoIP networks. One of the critical
features of the H.323 standard is the availability of a standards set which define not only a basic call
model, but also additional services. H.323 was the first VoIP standard that adopted the RTP IETF
standard for audio and video transport over IP networks.
IP
– Abbreviation for
Internet Protocol
. This is the TCP/IP protocol that determines the way data is
sent from one computer to another over internet. The messages are divided into data packets, routed
from the source network to the destination network and reassembled in the correct order to obtain the
original message. As each message is divided in a number of packets, each packet can be sent
through a different route over internet. This means it is possible for the data packets to be received in
a different order than the sending order. The IP protocol only delivers them. It is the TCP protocol
(Transmission Control Protocol) that orders the packets in the correct order.
The IP protocol is a connection-less protocol. IP corresponds to the level 3 network in the OSI
communication model (Open Systems Interconnection).
IP Address
– Abbreviation for
Internet Protocol Address
. The numerical address of a network
device or resource, in the format specified by the IP protocol (Internet Protocol). In the current format,
IPv4, the IP address is a sequence of 32 bits (4 bytes) divided in 4 groups of decimal numbers, each
group separated by a full stop. Each number can have a value between 0 and 255. An example would
be "127.0.0.1" or "213.154.120.170". The four numbers in the IP address are used for different
purposes, to identify a particular network and subsystem (host) of that network.
ISDN
– Abbreviation for
Integrated Services Digital Network
.
This represents the worldwide digital
network that offers high speed connection among terminal devices (phone, fax, PC) for a wide range
of telecommunication services, using the existing telephony infrastructure.
ISUP
– Abbreviation for
ISDN User Part
– this represents a component of the Signaling System #7,
used to establish phone calls in the public phone network with circuit switching. When a phone call is
established between one subscriber and another, several phone switching systems will be implied,
even from different countries. In order for the call to be correctly established, the switches signal, in
the network, the call information such as the caller/destination phone number, via ISUP messages.
INAP
– Abbreviation for
Intelligent Network Application Part
– signaling method used in the
intelligent network architecture. This represents a component of the SS7 protocol suite, usually above
the TCAP (Transaction Capabilities Application Part) level. INAP is a signaling protocol between a
SSP (Service Switching Point), the media resources of the network (intelligent devices) and a
centralized database, SCP (Service Control Point).
LCR
– Abbreviation for
Least Cost Routing
– This is the call delivery method that uses the lowest
cost network. Most of the times, there are several networks that can deliver a call, at different costs.
The LCR Softswitch contains a database with networks and the corresponding destinations and costs,
and will connect the call using the lowest cost network. This process determines a search for the
optimal traffic routes and a reduction in the call cost.
