... PSK or a certificate for authentication, various L2TP options as redial- timeout and attempts and of course all important PPP options. It also allows you to configure PPP for tunnel splitting because you can add routes as you want.
When applying your settings, all necessary configuration files are written accordingly (ipsec.conf, xl2tp.conf, options.xl2tpd, opensc.conf up and down scripts ...).
It relies on Openswan and xl2tp packages as the underlying protocol handlers.