> So why do ISP's use that hideous PPPoE?  What's wrong DHCP?  Are they
> paranoid that someone is going to hack a connection into their network or
> something?

A big advantage of PPPoE is that it looks just like dialup from our end.  You
don't have to tell the router about a new DSL customer (other than adding the
ATM interface); you just stick 'em in Radius and they're online.  Likewise,
Radius accounting works, so you can see how long they've been connected, etc.
This also makes it easy to allocate dynamic IP addresses out of a pool - again,
just like dialup.

Another reason is historical.  Originally, Cisco routers only supported bridged
DSL in the form of a giant Ethernet broadcast domain.  Customers could see each
other, for example.  Security and efficiency were big issues. Customers could
steal other people's IP addresses just by configuring any old IP address on
their PC, and it didn't scale well at all.  There were various filtering hacks
to help with these problems, but it was a big pain.  We considered switching to
PPPoE at times, ourselves.

Fortunately, Cisco came out with something called RBE - Routed Bridged
Encapsulation.  That lets the packets come in over ATM in the form of
Ethernet frames, but the router converts them into normal IP packets before
it presents them on an interface.  Essentially, it treats the Ethernet frame
as just another encapsulation of an IP packet.  Works great, scales great.
That's what we're using now.

--
Bruce Robertson, President/CEO                               +1-775-348-7299
Great Basin Internet Services, Inc.                     fax: +1-775-348-9412
http://www.greatbasin.net


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