On Wed, 28 Oct 2009, David E. Smith wrote:
With PPPoE, however, the end-user can't just plug in and go - they'll have to configure their PC, or a DSL modem, or something. That means a phone call to your tech support, most likely. In many cases, DHCP can lead to plug-and-play simplicity, which means they don't have to call you, and you don't have to answer their calls. Everyone wins. :)
One of the reasons for UUNET's PPPOE design was to reduce phone calls and configuration hassles. But in a different way. In the "old" days, people thought there would be separation between the ISP and the wholesale network. The idea that the provider could control/manage the CPE, like a cable set-top box, was probably more radical at the time than a dumb modem and PPPOE client on the PC. PPPOE can allow changing ISPs just by changing the username@domain, without needing to call wholesale provider's tech support and reconfiguring the circuit. You could even have multiple PC's sharing the same circuit, each connecting to different ISPs at the same time. Or use PPPOE to "call" a business' DSLAM pool for work access, and then call AOL's DSLAM pool for personal use. The concept of multiple "dialers" was well supported on most operating systems, and more familar to the public at the time than trying to set hostnames or read MAC addresses in DHCP configurations. In those days, VPN/IPSEC tunnel support wasn't very common. Businesses still had dial-up modem pools, X.25 PADs, and private PPP/PPPOE/PPPOA/PPPOx connections. Compared to the overhead for other point-to-point and tunneling protocols at the time, PPPOE's overhead didn't look that bad. And since it was based on PPP, PPPOE made route addressing (and other routing stuff) easy. Addressing a single host is the simple case of the more general router PPP information. As Milo used to say, with enough thrust you could get DHCP to do many of those same things too. There were a lot of experiments, and not all of them worked well. As they say, the world changed. Ethernet won, vertically integrated ISPs won, VPN won, and yes DHCP (with lots of options) won too. We can have a betamax/vhs-style argument of technical superiority; but the market made a choice.