There are two reasons to use L2TP to connect in to AAISP:
#As a backup for your existing AAISP circuit in the event of a fault.
#*Logging in over L2TP using your DSL credentials (ie email@example.com) from a different ISP will
#*This is enabled by default and available to everyone, there are no extra charges. Usage is taken from your quota in the usual way as if you were connecting over DSL.
#Connect in to AAISP over a third-party internet connection.