Altigen AltiContact Manager Version 4.6 Administration Manual page 252

Configuration Guidelines for NAT
In the corporate network, AltiWare and AltiGatekeeper are installed and
running on a host with private IP address 192.168.1.2. This gatekeeper
redirects requests from local IP phones and from remote IP phones through
VPN.
Both Router 1 and Router 2 are VPN-capable and compatible with each
other. (It is recommended that the routers come from same vendor.) A VPN
tunnel exists between these two routers. The local IP phones, IP Phone 1
and IP Phone 2, directly connect to the corporate network with private IP
address 192.168.1.100 and 192.168.1.101. And the three remote IP phones,
IP Phone 3, IP Phone 4 and IP Phone 5, connect to the branch office
network with private IP addresses 192.168.2.100, 192.168.2.101 and
192.168.2.102, respectively.
Setup
For the Corporate LAN:
• AltiWare
AltiWare is installed and running at same host with private IP
address 192.168.1.2.
• IP Phone 1 and IP Phone 2
When configuring the local IP Phone 1 and IP Phone 2, you should
set up the AWIP to AltiWare's IP address, which is 192.168.1.2.
For the Branch office LAN:
• IP Phone 3, IP Phone 4 and IP Phone 5
When configuring the remote IP phones, IP Phone 3, IP Phone 4
and IP Phone 5, you should set up the AWIP to AltiWare's IP
address, which is 192.168.1.2.
For the VPN Tunnel between the Two Private Networks:
You must set up a VPN tunnel to connect the two private networks. The
VPN setup procedure may be complicated and is generally performed by a
professional IT technician.
The following minimum guidelines need to be considered for setting up the
VPN tunnel:
• WAN Bandwidth - should be greater than the aggregate of
maximum VoIP session bandwidth usage. Each G.711 codec
requires 17 Kbps and each G.723.1 codec requires 85 Kbps.
• QoS - if the IP WAN network provides QoS (Quality of Service), it
should be configured to honor VoIP RTP packet transmission.
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