"Virtual" Network Cards

[Accessdabbler]

I use ADSL and my ISP (Sympatico) provides some software (Access Manager) to handle the connection process (PPPoE).

I'm curious how this software works. I've noticed that it appears to put a "virtual" NIC on my system. The actual NIC has a 169.x.x.x address and the "virtual: NIC gets the IP that the ISP assigns. However, the "virtual" NIC still has to operate through the real NIC to send and receive data packets.

Can anyone shed some light on how this gets accomplished?

 

[thedaver]

In linux, it is common to be able to bind a virtual interface for a kind of service/driver to a real NIC. This allows the machine's IP stack to talk in application-speak to the virtual interface which then talks to the "real" nic.

In the case of PPP or PPPoE you'll see a virtualized driver/nic instance that is the application's interface. Then this talks to the NIC and back again to execute real network traffic.

It's an abstraction technique for the most part.

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[cadaveca]

the reason you see the virtual adapter is because PPPoE is ppp ( or point to point) over ethernet..or analogue over digital, and the virtual adapter is what handles the conversion.

the only right answer to "why?" is: "why not?"