Draytek VigorAP 910C User Manual page 202

Available settings are explained as follows:
Item
ACS Settings
CPE Settings
Periodic Inform
Settings
STUN Settings
After finishing this web page configuration, please click OK to save the settings.
VigorAP 910C User's Guide
Description
URL/Username/Password – Such data must be typed according
to the ACS (Auto Configuration Server) you want to link. Please
refer to Auto Configuration Server user's manual for detailed
information. The setting for URL can be domain name or IP
address.
Such information is useful for Auto Configuration Server (ACS).
Enable– Check the box to allow the CPE Client to connect with
Auto Configuration Server.
Port – Sometimes, port conflict might be occurred. To solve
such problem, you might change port number for CPE.
DNS Server IP Address – Such field is to specify the IP
address if a URL is configured with a domain name.

Primary IP Address –You must specify a DNS server IP
address here because your ISP should provide you with usually
more than one DNS Server. If your ISP does not provide it, the
modem will automatically apply default DNS Server IP address:
194.109.6.66 to this field.

Secondary IP Address –You can specify secondary DNS
server IP address here because your ISP often provides you more
than one DNS Server. If your ISP does not provide it, the modem
will automatically apply default secondary DNS Server IP
address: 194.98.0.1 to this field.
The default setting is Enable. Please set interval time or
schedule time for the AP to send notification to VigorACS
server. Or click Disable to close the mechanism of notification.
Interval Time – Type the value for the interval time setting. The
unit is "second".
The default is Disable. If you click Enable, please type the
relational settings listed below:
Server Address – Type the IP address of the STUN server.
Server Port – Type the port number of the STUN server.
Minimum Keep Alive Period – If STUN is enabled, the CPE
must send binding request to the server for the purpose of
maintaining the binding in the Gateway. Please type a number as
the minimum period. The default setting is "60 seconds".
Maximum Keep Alive Period – If STUN is enabled, the CPE
must send binding request to the server for the purpose of
maintaining the binding in the Gateway. Please type a number as
the maximum period. A value of "-1" indicates that no
maximum period is specified.
192