I wasn't aware that LECs have the money to provide a DSLAM port per pair. =) PPPoA/E wasn't invented to prevent DSL sharing (not possible), but was the result of extending the dial-up approach of PPP with usernames and passwords to provide end-users IP connectivity. As Arie mentions in his posting, the separation of physical link termination and session termination, done in the dial-up world at the time, lent to setting up DSL in the same manner. You don't have to read too many commentaries on IRB & RFC 1483 to recognize that that approach is all that great, either. Frank -----Original Message----- From: William McCall [mailto:william.mccall@gmail.com] Sent: Thursday, April 23, 2009 7:24 AM To: nanog@nanog.org Subject: Re: Broadband Subscriber Management My understanding of the PPPoA/E deal is that SPs (originally) wanted to prevent some yahoo with a DSL modem from just being able to hook in to someone's existing DSL connection and using it, so they decided to implemement PPPoA and require some sort of authentication to prevent this scenario. <snip>