Rob,
While similar in names, PPPoA and PPPoE are different and incompatible approaches. The PPPoA is about taking the PPP frames, directly chopping them into ATM cells and having them sent via the DSLAM to the BRAS. No special processing of these PPP frames is taking place (apart from using the usual AAL5 ATM adaptation layer and possibly adding a SNAP header). This approach requires that you have an ATM interface directly built into your router.
The PPPoE is originally a LAN access technology in which the PPP packets were transported over an Ethernet LAN to an access concentrator, thereby allowing dedicated, individual and isolated PPP sessions from possibly many stations on the LAN to be built towards the access concentrator. PPPoE involves encapsulating the PPP frames into Ethernet frames with an additional header that allows to differentiate between several simultaneous sessions on the same LAN. Also, before the PPP session can come up, the end station has to perform a so-called PPPoE Active Discovery procedure in which it searches for available access concentrators, registers with one of them and obtains a session ID. Only then, the PPP session (carried over the Ethernet) can come up. This technology was later retaken into DSL service as well. Note that even with DSL, the entire Ethernet+PPPoE+PPP+IP+... is carried from the end host towards the BRAS, as opposed to the relatively simple PPP+IP+... with PPPoA.
One of the great confusions about this is whether the PPPoE is applied on an Ethernet interface (assuming that there is a separate external Ethernet-to-DSL modem connected to the interface) or directly on a built-in DSL/ATM interface. The PPPoE stays still the same, the difference is only where does the additional stage of chopping the entire Ethernet frames (i.e. Ethernet+PPPoE+PPP+payload) into ATM cells take place. The configuration of PPPoE on Ethernet interfaces is therefore sometimes called PPPoEoE while configuring the PPPoE on a DSL interface is sometimes called PPPoEoA.
In any case, as you can see so far, the PPPoE and PPPoA use different approaches to perform the same trick. They are not interchangeable and they cannot be configured on arbitrary interfaces. If your service provider requires PPPoA and not PPPoE, and your router does not contain DSL interface then sadly, there is no way to make this work.
Please do an inquiry to our service provider to make absolutely sure what kind of PPPoX it is requesting from you, and let us know.
Best regards,
Peter
