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19 Configuring Autodetect
Autodetect enables the modem to automatically detect and
configure a valid ATM VC at startup. Autodetect eliminates the need
to have users configure VC values as described in “
Configuring the
ATM VC” on page
58.
How Autodetect Works
When enabled, Autodetect attempts to establish a DSL connection
with the ISP using VC values (VPI/VCI) selected in either of two
ways:
f from a pre-determined list preconfigured on the modem
f from the complete range of valid values
Note
The method of operation is preconfigured by the ISP and cannot
be changed using the Web-based interface.
A valid connection is found when a PPP, EoA, or IPoA interface is
found on the ISP's access server. If the initial VPI/VCI values do not
detect a valid connection, then Autodetect tries again using the next
set of available values. When a successful connection is
discovered, that connection is used for the current session and the
VPI/VCI values are "remembered" for initial use the next time the
modem starts up.
Autodetect Modes
Autodetect can be used to establish PPPoE, PPPoA, IPoA-1577
and EoA connections and can be configured in either of two modes:
bridging mode and routing mode. These modes are specific to the
Autodetect feature and are configured in addition to the system
operating mode defined on the modem.
f When Autodetect is configured in bridging mode, it can
detect the presence of PPPoE and EoA interfaces on the
access server. In this mode, the modem must be
configured as a bridge and a PPPoE or DHCP client is
expected to be running on the LAN PC (behind the
modem).
f When configured in routing mode, Autodetect can detect
PPPoE, EoA, PPPoA, or IPoA-1577 interfaces on the
access server. Autodetect searches for these interfaces in
the order stated. Depending on the interface detected,
Autodetect creates a PPP, an EoA, or an IPoA interface on
the modem. In this mode, the modem is expected to be
configured as a router.
