Panasonic KX-TDA0490, Getting Started

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A1 VoIP Requirements
Getting Started 49
Is network address translation (NAT/NAPT) disabled?
In a network where address translation techniques (e.g., NAT/NAPT) are used to convert between
global and local IP addresses, VoIP communications based on the H.323 protocol cannot be carried
out appropriately. Generally, NAT/NAPT are features that are available with routers.
Note
If the router on the network supports the "H.323 NAT" feature, it may be possible to have VoIP
communications over the network. For more information, consult your network administrator.
Does only a single router provide access to the IP network?
In a dual network, 2 routers provide access to the IP network as shown in the diagram below.
However, the VoIP Gateway Card cannot take the advantage of having 2 routers as access points to
the IP network.
For example, if router A, whose IP address is assigned as the default gateway IP address of the card,
fails, VoIP communications are no longer possible; the card is not able to switch its default gateway
from router A to router B to access the IP network. For more details about the default gateway setting,
refer to "2.2.1 Network Parameters" of the VoIP Gateway Card Programming Guide.
Router
(NAT/NAPT enabled)
IP Network
Global IP Address Domain
Local IP Address Domain
IP Network
Router A Router B
Default gateway
of the card:
Router A