Chapter 1 Introducing the ISG50
ISG50 User’s Guide
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1.1.3.1 All-in-one
Use the ISG50 to provide VoIP and security services.
Figure 2 All-in-one Application Scenario
VoIP Services:
• VoIP phones and smartphones can make internal calls and external calls.
• Least Cost Routing (LCR) dialing rules put calls through the appropriate outbound line. Long
distance calls (to C in the figure) use VoIP and local calls (to D) use PSTN or ISDN.
• Auto attendant menu systems act as automatic switchboard operators to help route incoming
calls to the proper extension.
• Customers (like B) use Web services such as Click To Talk, Skype, or Google Voice to call in.
• Voice mail stores voice messages for users and can also forward them by email.
• Conference room extensions allow callers from within and outside your organization to join
conference calls by dialing a conference room extension.
• Use call recording to record all calls for specific extensions or trunks or let users record calls.
• VLAN and QoS enhance voice quality.
•Fax over IP.
• PSTN or ISDN outbound voice trunks and fax service.
Security Services:
• Firewall protected Internet access and DMZ network for publicly accessible servers.
• IPSec VPN-secured VoIP services and internal server access for teleworkers (A and C in the
diagram).
• Multiple WAN gives fail-over protection for VPN connections and VoIP.
1.1.3.2 DMZ Installation
Use the ISG50 with a USG, ZyXEL’s Unified Threat Management (UTM) firewall to add more security
services like IDP and anti-virus. If you connect the ISG50 to a USG model’s DMZ, the ISG50
FAX
ITSP
PSTN/ISDN
ISG
DMZ
LAN
A
C
Headquarters
B
D
WAN1
WAN2
