Subject: Re: in-kernel PPPoE
To: None <tech-kern@netbsd.org>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: tech-kern
Date: 04/11/2001 09:44:12
>> In my famous naivity I tried to use an old 486 @ 50 MHZ as my DSL
>> router.  Running the rp-pppoe pkg from pkgsrc this results in
>> abysmal performance [...]

> Dumb question...  PPPeE implies that your DSL modem provides ethernet
> yes?

Yes and no.  PPPoE is a method of encapsulating PPP frames in Ethernet
packets (see RFC 2516).  The box accepts Ethernet (typically 10baseT)
signals and Ethernet framing, but packets not having one of the PPPoE
values in the type field won't go very far.

It's a somewhat broken design, in that dialup PPP links typically have
MTUs of 1500, but the Ethernet MTU and the various overheads imposes a
lower limit (1475? I use 1400) on the effective MTU.  And it's amazing
the number of things which break when you're behind a link with an MTU
lower than 1500. :-(

> What does the PPP bit get you?

Connectivity.  There are DSL providers out there (eg, mine) that simply
won't talk anything but PPPoE.

					der Mouse

			       mouse@rodents.montreal.qc.ca
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