jamal writes:
>
> So lets try to identify what the other concerns are.
> Michal, i think this is a very good compromise if you can pull it.
> Maybe it will start with just PPPOE; and i suspect L2TP to follow
> it needs something similar.
I think we'd need to examine L2TP and see just how well it can
co-exist with PPPoE/PPPoATM. Doing PPPoE is easy... figuring out how
to do it in a manner which can co-exist with PPPoX is hard.
> I think the socket solution is acceptable if you can make it to be
> for more than just pppoe. This is my opinion however.
> I am afraid some of the people that i know to be concerned of this whole
> socket idea havent spoken yet ;-> The words "maintainance nightmare" were
> not really mine.
Yes... I'm really looking forward to hearing Andi's, Paul's and Dave's
comments (if they ever manage to read through all of the stuff we sent
around yesterday).
>
> sid should be enough for pppoe, no?
99.99999% of the time sid alone suffices. However, you have a problem
if you have multiple connections --- because the remote access
concentrator's may all assign you the same sid, in which case you must
identify them by MAC address as well. My view is that you can think
of sid's as analogous to TCP/UDP ports --- they're useless without an
IP address.
Let's not be quick to jump to conclusions as to how PPPoE will be
used. I've heard a rumour that PPPoE is being considered for use here
at the University of Waterloo to provided authenticated ethernet
access at public ethernet access points. Such a solution makes some
sense since one could leverage the existing RADIUS/PPP infrastructure
used to provide dial-up access. The point here is is that we may see
PPPoE being used beyond the traditional ADSL context (funny how ADSL
is already "traditional").
>
> There is always a unique way to identify a flow regardless of the
> protocol. Look at the way UDP does it (because it is simple).
>
I don't understand what you mean by this, please elaborate (or refer
to a specific code fragment).
My concern is that you need to know something about the protocol to be
able to identify the flow, since you need to be able to parse the
packet header and extract those bits that identify the stream.
Is it possible to find some sort of abstract addressing scheme which
can be used by PPPoE, PPPoATM, L2TP, etc...? (Essentially is it
possible to come up with a sockaddr_pppox which is appropriate for all
of them?) The answer to that IMO will determine whether or not you
can make AF_PPPOX work. I don't know the answer to that.
As a side note... I've been informed that our favorite PPPoE-using
ADSL provider's network architecture (Bell Nexxia) includes PPPoE,
L2TP, and PPPoUDP. By that I mean that it is actually possible for
you to send a packet which is carried by all of these protocols before
it reaches your ISP's IP network (in the case that your ISP is not
Sympatico). If your ISP is Sympatico, then you get to skip the
PPPoUDP step.
Michal Ostrowski
mostrows@xxxxxxxxxxxxxxxxx
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