What is PPPoA and PPPoE?
PPPoA (point-to-point protocol over ATM) and PPPoE (point-to-point protocol over Ethernet) are authentication and connection protocols used by many service providers for broadband Internet access. In particular, many LECs (local exchange carriers) such as Verizon, SBC and Bell South use these protocols to manage their ADSL users. These protocols are popular with the service providers because they make the broadband connection look like a dial-up connection from an accounting and billing perspective. Also, they let the service provider get more users onto the same facilities by logging off users that have no activity.
Cable modem services and business quality DSL services don't require PPPoE and PPPoA because they are true always-on services. If your service provider is using PPPoE or PPPoA, you need to make sure that your access device or VPN box supports the protocol. These vary by service provider, so you should first check with them to see what access devices they support.