netdev
[Top] [All Lists]

Re: [PATCH, untested] Support for PPPOE on SMP

To: Paul Mackerras <paulus@xxxxxxxxx>
Subject: Re: [PATCH, untested] Support for PPPOE on SMP
From: Ben Greear <greearb@xxxxxxxxxxxxxxx>
Date: Wed, 25 Jun 2003 15:53:10 -0700
Cc: Jamal Hadi <hadi@xxxxxxxxxxxxxxxx>, Stephen Hemminger <shemminger@xxxxxxxx>, mostrows@xxxxxxxxxxxxxx, rusty@xxxxxxxxxxxxxxx, davem@xxxxxxxxxx, netdev@xxxxxxxxxxx, dfs@xxxxxxxxxxxxxxxxxx, carlson@xxxxxxxxxxxxxxx
In-reply-to: <16122.8374.178895.287907@nanango.paulus.ozlabs.org>
Organization: Candela Technologies
References: <20030625072602.529AF2C0B9@lists.samba.org> <1056547262.1945.1436.camel@brick.watson.ibm.com> <20030625091531.5ebed618.shemminger@osdl.org> <20030625122128.V84526@shell.cyberus.ca> <20030625093902.7431efc3.shemminger@osdl.org> <20030625125518.N84526@shell.cyberus.ca> <16122.8374.178895.287907@nanango.paulus.ozlabs.org>
Sender: netdev-bounce@xxxxxxxxxxx
User-agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030529
Paul Mackerras wrote:
Jamal Hadi writes:


a protocol or implementation which wishes to do state maintanance
properly oughta be able to do the synchronization on its own.
Separation between policy and mechanism has been the strength of unix.
A clean separation between control and a data path is very important.
Control protocols tend to be very rich environments which are
constantly changing. Take STP, there are so many features that could be
added to STP that are much harder to add because it is in the kernel.

Maybe what needs to be looked at i sthe design of pppoe or ppp.


OK, now that we have had our little flight of fancy about what things
will be like once we get to heaven, can we talk about this bastard
protocol called PPPoE? :)

Or are you going to go personally to each ISP in the world and tell
them they shouldn't use PPPoE? :)

In any case the problem isn't strictly with PPPoE, since ethernet
doesn't reorder packets on the wire.  The problem is that the lower
parts of the Linux network stack lose information.

Paul.

Nothing is guaranteed, but you may be right at least most of the time. Btw, if you want a proprietary tool that will emulate an ethernet network that reorders packets, I write such a thing and will give it to you. It could help you with testing perhaps.

Also, if you have a PCMCIA Zircom NIC, it seems to reorder packets
just for the hell of it (and no, I'm not using a dual-cpu laptop :))

I don't know of any other protocols that can't handle reordering,
since most of them seem to be designed to run over the real internet,
where reordering/drop/duplication is a part of life.

Ben




--
Ben Greear <greearb@xxxxxxxxxxxxxxx>       <Ben_Greear AT excite.com>
President of Candela Technologies Inc      http://www.candelatech.com
ScryMUD:  http://scry.wanfear.com     http://scry.wanfear.com/~greear



<Prev in Thread] Current Thread [Next in Thread>