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diff --git a/zarb-ml/mageia-discuss/20101025/002630.html b/zarb-ml/mageia-discuss/20101025/002630.html new file mode 100644 index 000000000..bd1fba0e3 --- /dev/null +++ b/zarb-ml/mageia-discuss/20101025/002630.html @@ -0,0 +1,158 @@ +<!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=%3C20101025064101.GB10424%40maude.comedia.it%3E"> + <META NAME="robots" CONTENT="index,nofollow"> + <META http-equiv="Content-Type" content="text/html; charset=us-ascii"> + <LINK REL="Previous" HREF="002619.html"> + <LINK REL="Next" HREF="002631.html"> + </HEAD> + <BODY BGCOLOR="#ffffff"> + <H1>[Mageia-discuss] network balancing by default</H1> + <B>Luca Berra</B> + <A HREF="mailto:mageia-discuss%40mageia.org?Subject=Re%3A%20%5BMageia-discuss%5D%20network%20balancing%20by%20default&In-Reply-To=%3C20101025064101.GB10424%40maude.comedia.it%3E" + TITLE="[Mageia-discuss] network balancing by default">bluca at vodka.it + </A><BR> + <I>Mon Oct 25 08:41:01 CEST 2010</I> + <P><UL> + <LI>Previous message: <A HREF="002619.html">[Mageia-discuss] network balancing by default +</A></li> + <LI>Next message: <A HREF="002631.html">[Mageia-discuss] network balancing by default +</A></li> + <LI> <B>Messages sorted by:</B> + <a href="date.html#2630">[ date ]</a> + <a href="thread.html#2630">[ thread ]</a> + <a href="subject.html#2630">[ subject ]</a> + <a href="author.html#2630">[ author ]</a> + </LI> + </UL> + <HR> +<!--beginarticle--> +<PRE> +On Mon, Oct 25, 2010 at 12:00:46AM +0200, Maarten Vanraes wrote: +><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> +</I>><i>First off, the timing of this proposal is probably too soon, i just wanted to +</I>><i>get it out there, in case i forgot later. +</I> +open an enhancement on initscripts :P + +>><i> >A.) by default, add for every interface, a little advanced routing which +</I>>><i> >makes packets return from the same way they came. +</I>>><i> >This usually is only useful with incoming packets, but can still be useful +</I>>><i> >if laptops have for example 2 gateways because the wifi is still on and +</I>>><i> >the cable is too. That would mean that from both interfaces it'd be +</I>>><i> >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 effect +</I>><i>on new outgoing packets; this step doesn't change anything for new outgoing +</I>><i>packets. and this can even be used on interfaces that aren't used as default +</I>><i>gateway. +</I>i did not understood the second and third sentence in A.), then. + +anyways i believe A is useful and can be implemented without any issue + +><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 be +</I>><i>usefull, it might well be only a dhcp failure; we should try with the current +</I>><i>lease if possible. +</I>if it is expired you should not. doing this will result in duplicate +ips. + +><i>E is a bit of an extra (it's not really routing, but a DNS that's down (does +</I>><i>not answer) could well be eliminated (not sure if this should be done +</I>><i>separately or not)) OTOH, failure of the recursive DNS of the ISP seems to be +</I>><i>somewhat frequent in my experience. +</I>so a connectivity issue will leave users without dns? + +><i>C+D are tricky: D is even a bit of a grey area; my ISP frequently has a few +</I>><i>routes broken. icmp can definately not be relied on in all cases. and even if +</I>><i>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 icmp in +</I>><i>a list and ping those. but for that matter, it doesn't have to be icmp; we +</I>><i>could easily have a list of public services that can be connected to. but is +</I>><i>this really what we want? +</I>><i> +</I>><i>We could even just monitor how much packets are unreplied to per interface and +</I>><i>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> ++1 +you are considering the only scenario of a home user. doing some things +you propose above would prevent using mageia in any medium sized +network. (i.e. i could not use my mageia laptop at work) + +><i>remember that right now only A(+B) is used; and having balanced default routes +</I>><i>would probably mean that there is 50% packet loss, instead of 100% in most +</I>><i>cases. +</I> +which may be worse. +if nothing works the user will try switching to a different connection +if stuff do not work at random the user will not know what to do. + +btw, the assumption about 50% is flawed, i don't know if it is an +oversimplification or a failure to understand how load balancing over +multiple network links work in practice. +it is not round-robin, it is route-based (on ip hash) +the result of a failure upstream will result in the user being able to, +say, watch some videos on youtube, but not update her fb profile, or +worse. + +><i>also remember that if the metrics are the same for some reason, you will get +</I>><i>much stranger things when both are working perfectly. +</I> +L. + +btw, there is no need to cc me on discussions, in fact it breaks my +filters. + +-- +Luca Berra -- <A HREF="https://www.mageia.org/mailman/listinfo/mageia-discuss">bluca at vodka.it</A> + + + + +</PRE> + + +<!--endarticle--> + <HR> + <P><UL> + <!--threads--> + <LI>Previous message: <A HREF="002619.html">[Mageia-discuss] network balancing by default +</A></li> + <LI>Next message: <A HREF="002631.html">[Mageia-discuss] network balancing by default +</A></li> + <LI> <B>Messages sorted by:</B> + <a href="date.html#2630">[ date ]</a> + <a href="thread.html#2630">[ thread ]</a> + <a href="subject.html#2630">[ subject ]</a> + <a href="author.html#2630">[ 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> |