- with PPPoE-speaking Internet DSL services where a PPPoE-speaking modem-router connects to the DSL service. Here both ISP and modem-router need to speak PPPoE. (Note that in this case, the PPPoE-over-DSL side of things is occasionally referred to as PPPoEoA, for ‘PPPoE over ATM’.)
- or when a PPPoE-speaking DSL modem is connected to a PPPoE-speaking Ethernet-only router using an Ethernet cable. For such two-box systems, DSL modem plus Ethernet-only router, PPPoE is now the preferred solution.
In fact, the term ‘PPPoE’ is used sometimes confusingly to refer to either or both of two things: (i) a modem-to-router protocol; (ii) on the DSL side of things, a part of a protocol stack (part group of nested protocols) which is PPPoEoA. (See the section on protocol stacks below.); or both (i) and (ii) chained together.
It is possible to find DSL modems, such as the Draytek Vigor 120, where PPPoE is confined to the ethernet link between a DSL modem and a partnering router, and the ISP does not speak PPPoE at all (but rather PPPoA).
Older types of link used for connecting modems to PCs or to routers, RS232 and then USB 1.1, are not fast enough to handle DSL services, so by the mid-1990s a new type of link was urgently needed (this being some years before the arrival of USB 2.0), and PPPoE became the solution for tunneling packets over the DSL connection to the ISP's IP network, and from there to the rest of the Internet.
For more information please click here