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diff --git a/zarb-ml/mageia-discuss/20101025/002631.html b/zarb-ml/mageia-discuss/20101025/002631.html new file mode 100644 index 000000000..bc57897ad --- /dev/null +++ b/zarb-ml/mageia-discuss/20101025/002631.html @@ -0,0 +1,181 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN"> +<HTML> + <HEAD> + <TITLE> [Mageia-discuss] network balancing by default + </TITLE> + <LINK REL="Index" HREF="index.html" > + <LINK REL="made" HREF="mailto:mageia-discuss%40mageia.org?Subject=Re%3A%20%5BMageia-discuss%5D%20network%20balancing%20by%20default&In-Reply-To=%3C201010250857.38844.maarten.vanraes%40gmail.com%3E"> + <META NAME="robots" CONTENT="index,nofollow"> + <META http-equiv="Content-Type" content="text/html; charset=us-ascii"> + <LINK REL="Previous" HREF="002630.html"> + <LINK REL="Next" HREF="002651.html"> + </HEAD> + <BODY BGCOLOR="#ffffff"> + <H1>[Mageia-discuss] network balancing by default</H1> + <B>Maarten Vanraes</B> + <A HREF="mailto:mageia-discuss%40mageia.org?Subject=Re%3A%20%5BMageia-discuss%5D%20network%20balancing%20by%20default&In-Reply-To=%3C201010250857.38844.maarten.vanraes%40gmail.com%3E" + TITLE="[Mageia-discuss] network balancing by default">maarten.vanraes at gmail.com + </A><BR> + <I>Mon Oct 25 08:57:38 CEST 2010</I> + <P><UL> + <LI>Previous message: <A HREF="002630.html">[Mageia-discuss] network balancing by default +</A></li> + <LI>Next message: <A HREF="002651.html">[Mageia-discuss] network balancing by default +</A></li> + <LI> <B>Messages sorted by:</B> + <a href="date.html#2631">[ date ]</a> + <a href="thread.html#2631">[ thread ]</a> + <a href="subject.html#2631">[ subject ]</a> + <a href="author.html#2631">[ author ]</a> + </LI> + </UL> + <HR> +<!--beginarticle--> +<PRE>Op maandag 25 oktober 2010 08:41:01 schreef Luca Berra: +><i> On Mon, Oct 25, 2010 at 12:00:46AM +0200, Maarten Vanraes wrote: +</I>><i> >Op zondag 24 oktober 2010 22:39:29 schreef Luca Berra: +</I>><i> >> On Sun, Oct 24, 2010 at 11:43:28AM +0200, Maarten Vanraes wrote: +</I>><i> >> >I would propose the following: +</I>><i> >First off, the timing of this proposal is probably too soon, i just wanted +</I>><i> >to get it out there, in case i forgot later. +</I>><i> +</I>><i> open an enhancement on initscripts :P +</I> +imho, this in itself is wrong; i want network-scripts to be split off from +initscripts; especially if we're going to use systemd later on. + +><i> >> >A.) by default, add for every interface, a little advanced routing +</I>><i> >> >which makes packets return from the same way they came. +</I>><i> >> >This usually is only useful with incoming packets, but can still be +</I>><i> >> >useful if laptops have for example 2 gateways because the wifi is +</I>><i> >> >still on and the cable is too. That would mean that from both +</I>><i> >> >interfaces it'd be possible to use ssh or vnc or whatever. +</I>><i> >> +</I>><i> >> this is possible with incoming packets, but, how do you select the +</I>><i> >> source of a new one? +</I>><i> > +</I>><i> >this step is only for the replies of incoming packets and never has any +</I>><i> >effect on new outgoing packets; this step doesn't change anything for new +</I>><i> >outgoing packets. and this can even be used on interfaces that aren't +</I>><i> >used as default gateway. +</I>><i> +</I>><i> i did not understood the second and third sentence in A.), then. +</I>><i> +</I>><i> anyways i believe A is useful and can be implemented without any issue +</I> + +it will not conflict with current situation. + + +><i> >possible problems: +</I>><i> >A) interface down +</I>><i> >B) DHCP expired +</I>><i> >C) gateway down +</I>><i> >D) further routing down +</I>><i> >E) DNS down +</I>><i> > +</I>><i> >A is trivial, so we'll just skip that one. +</I>><i> > +</I>><i> >B seems easy to do too; however, reusing the last DHCP lease could still +</I>><i> >be usefull, it might well be only a dhcp failure; we should try with the +</I>><i> >current lease if possible. +</I>><i> +</I>><i> if it is expired you should not. doing this will result in duplicate +</I>><i> ips. +</I> +ok. + +><i> >E is a bit of an extra (it's not really routing, but a DNS that's down +</I>><i> >(does not answer) could well be eliminated (not sure if this should be +</I>><i> >done separately or not)) OTOH, failure of the recursive DNS of the ISP +</I>><i> >seems to be somewhat frequent in my experience. +</I>><i> +</I>><i> so a connectivity issue will leave users without dns? +</I> + +more the other way around; in the event of dns failure; the dns of the other +gateway could be used. if it would be a routing issue to the DNS (and others), +then other rules could be triggered (C+D) + + +><i> >C+D are tricky: D is even a bit of a grey area; my ISP frequently has a +</I>><i> >few routes broken. icmp can definately not be relied on in all cases. and +</I>><i> >even if you ping your gateway, you don't know if it goes any further. +</I>><i> > +</I>><i> >This could be circumvented by putting known servers that actually echo +</I>><i> >icmp in a list and ping those. but for that matter, it doesn't have to be +</I>><i> >icmp; we could easily have a list of public services that can be +</I>><i> >connected to. but is this really what we want? +</I>><i> > +</I>><i> >We could even just monitor how much packets are unreplied to per interface +</I>><i> >and choose that. +</I>><i> > +</I>><i> >Or we could try to have each retry of unreplied packet go through the next +</I>><i> >default route. +</I>><i> > +</I>><i> >Or we could just not handle that (like it is now). +</I>><i> +</I>><i> +1 +</I>><i> you are considering the only scenario of a home user. doing some things +</I>><i> you propose above would prevent using mageia in any medium sized +</I>><i> network. (i.e. i could not use my mageia laptop at work) +</I> +I don't see what you mean by this. i list 4 options; knowing full well that +some of those options are not usefull by default. also, this is only required +if more than one default gateway is active; which is a small percentage in +itself. (my personal favourite is having it sent to the other default gateway +after failure; or seeing which has more unreplied packets; and then check some +public services) + +><i> >remember that right now only A(+B) is used; and having balanced default +</I>><i> >routes would probably mean that there is 50% packet loss, instead of 100% +</I>><i> >in most cases. +</I>><i> +</I>><i> which may be worse. +</I>><i> if nothing works the user will try switching to a different connection +</I>><i> if stuff do not work at random the user will not know what to do. +</I> +it could be worse, depending on the type of person. + +><i> btw, the assumption about 50% is flawed, i don't know if it is an +</I>><i> oversimplification or a failure to understand how load balancing over +</I>><i> multiple network links work in practice. +</I>><i> it is not round-robin, it is route-based (on ip hash) +</I>><i> the result of a failure upstream will result in the user being able to, +</I>><i> say, watch some videos on youtube, but not update her fb profile, or +</I>><i> worse. +</I> +i meant on average in total, depending on what kind of balancing is used. + +><i> >also remember that if the metrics are the same for some reason, you will +</I>><i> >get much stranger things when both are working perfectly. +</I>><i> +</I>><i> L. +</I>><i> +</I>><i> btw, there is no need to cc me on discussions, in fact it breaks my +</I>><i> filters. +</I> +sorry, +</PRE> + + +<!--endarticle--> + <HR> + <P><UL> + <!--threads--> + <LI>Previous message: <A HREF="002630.html">[Mageia-discuss] network balancing by default +</A></li> + <LI>Next message: <A HREF="002651.html">[Mageia-discuss] network balancing by default +</A></li> + <LI> <B>Messages sorted by:</B> + <a href="date.html#2631">[ date ]</a> + <a href="thread.html#2631">[ thread ]</a> + <a href="subject.html#2631">[ subject ]</a> + <a href="author.html#2631">[ author ]</a> + </LI> + </UL> + +<hr> +<a href="https://www.mageia.org/mailman/listinfo/mageia-discuss">More information about the Mageia-discuss +mailing list</a><br> +</body></html> |