BELGACOM Forum 523, Mounting And Commissioning Manual

Page: 119 / 244

SIP Telephony 117
Voice over IP (VoIP)
SIP Telephony
The SIP Internet (Session Initiation Protocol) protocol provides
you with a low-cost, standardised option for telephoning via IP-
based networks. The Forum 523/524 enables you to use external
SIP telephone connections (“SIP trunk lines”). The Forum 523/
524 communications system supports configuration of standard
SIP lines with one call number for each as well as extension-capa-
ble SIP-DDI lines with base call number and extension.
Furthermore, internal SIP subscribers, SIP telephones or SIP
telephony software are also supported (see also
Quick Start :
External SIP Line starting on page 104 and Internal SIP Telephony
starting on page 105).
External SIP Connections
The Telephony : Trunks : Route menu gives you the option to
configure a bundle overflow, which automatically occupies a sec-
ond line in case of a breakdown or over-occupancy of the SIP con-
nection. You can also set up your system to route certain types of
calls, such as international calls, to an SIP connection.
Note: You will need a Media Gateway card for SIP telephony.
You will also need a fast Internet connection such as DSL for SIP
telephony.
You will also usually need the services of a SIP provider. A SIP
provider operates a special server (the SIP Registrar) to handle
connections. The SIP provider also operates a gateway to the
ordinary telephone network which users pay to use and which
enables the SIP provider to provide calls to the telephone net-
work. A SIP connection can also accept incoming calls from the
telephone network.
The same voice transmission techniques as those explained in
Fundamentals starting on page 107 are used for SIP telephony.
SIP telephony has the following distinctive features:
z
Subscribers are identified through an e-mail-like “SIP ID” such
as 12345@domain.net or name@sip-provider.com.