An OC-12 is 622 Mb/s I don't think he has one. His internal lan speed is probably 100Mb/s fast ethernet but then again I doubt that's his external internet speed. PPPoE overhead is the space it takes to encapsulate the packets using the point to point protocal. Oversubscription is the amount of people an ISP subscribes compared to the amount of bandwidth availible. Most residential dsl/cable ISPs are somewhere around 1:50. This is what causes latency, headaches and prime time slow downs - when the ISP "guesses " wrong about oversubscription. Oversubscription is also what allows the ISP to make money and stay in business. Hope this helps with the terms,