Draytek Vigor 160 Series User Manual page 52

Available settings are explained as follows:
Item
Enable Channel 3/4/5
WAN Type
General Settings
42
Description
Check it to enable this channel.
The connections and interfaces created in every channel may
select a specific WAN type to be built upon.
VPI - Type in the value provided by your ISP.
VCI - Type in the value provided by your ISP.
Protocol - Select a proper protocol (PPPoA, PPPoE or MPoA)
for this channel.
Encapsulation - Choose a proper type for this channel. The
types will be different according to the protocol setting that
you choose.
Vigor160 Series User's Guide