Lancom 1722 VoIP User Manual page 18

LANCOM 1722 VoIP – LANCOM 1724 VoIP
Chapter 1: Introduction
Connecting local ISDN lines with a remote SIP gateway
Companies with nation-wide and internationally distributed sites are often
interconnected with VPN already. A LANCOM VoIP Router can be used not
only to connect the SIP and ISDN telephones at a branch office to the SIP-PBX
at headquarters; it can also integrate local ISDN networks into corporate com-
munications with help of the "SIP Gateway" function.
The SIP gateway is active for outgoing and incoming calls.
Local ISDN network
Advantages of the SIP gateway:
18
A company headquarters in New York can, for example, use a LANCOM
VoIP Router with SIP gateway located at the Los Angeles branch office to
telephone with customers and suppliers located in Los Angeles at local
rates ("local break-out").
For improved availability to customers located abroad, the New York
headquarters can, for example, use a LANCOM VoIP Router with SIP gate-
way located at their sales office in Italy. Customers can then reach support
or service numbers via a standard national telephone number. Calls from
the local ISDN network are received and directed within the company net-
work to the responsible employee. Call routing can be used which identi-
fies the customer's calling number and automatically selects the
appropriate connection to be used for forwarding the call.
LANCOM VoIP
Router
Branch office
The local ISDN connection at any site is available for use by any of the
offices throughout the entire company.
National and international long-distance calls can be mapped to local or
regional calls, so saving costs.
Internet
VPN tunnel
LANCOM
Headquarters
VoIP telephones
VoIP PBX