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Re: PPPoverEthernet vs. PPPoverATM

On Fri, Feb 22, 2002 at 04:47:02PM +0100, VERBEEK, Francois wrote:
| Note that PPPoE is anyway encapsulated in ATM so you eventually get an
| additional (and useless) overhead.

Possibly.  I expect, but have no facts or proof, that a "dsl modem"
will strip out the ethernet frames and use only the payload as the
data part of the ATM cells.  Thus the ATM cell will only contain the
PPP packet, not the entire ethernet frame.  If this is the case, using
    PPPoE->ATM bridge->DSL signalling->DSLAM->PPP(oE)->internet
will be no worse than
    PPPoA->DSL signalling->PPPoA->internet
apart from the "extra" ethernet segments.

The real difference, then, is ATM vs. ethernet at your box (and the
availability of a corresponding setup at the ISPs end).

| Some say you never feel it, others say you do.
| Anyway, to avoid unnecessary encapsulation is always an advantage. 


My current setup is
    (TCP/IP) ethernet -> ATM bridge (cicso 677) -> DSL signalling ->
        DSLAM (ATM at ISPs end) -> internet
and it works great.



Microsoft is to operating systems & security ....
                                     .... what McDonald's is to gourmet cooking

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