The standard for PPP over Ethernet is L2TP. The pre-standard

woody wrote: proprietary

implementations were L2F and PPTP, from Cisco and Microsoft, respectively. I believe you'll find Internet Drafts on all three.

L2TP is currently an Internet Draft: <http://www.ietf.org/internet-drafts/draft-ietf-pppext-l2tp-11.txt> L2F was an Internet Draft, but has since been published as an RFC: <ftp://ftp.isi.edu/in-notes/rfc2341.txt> PPTP was an Internet Draft but has since been deleted (see note): <http://www.ietf.org/internet-drafts/draft-ietf-pppext-pptp-06.txt> -Richard