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From: Marek Lindner <lindner_marek@yahoo.de>
To: b.a.t.m.a.n@lists.open-mesh.org
Subject: Re: [B.A.T.M.A.N.] [PATCH 5/5] batman-adv: avoid temporary routing loops by being strict on forwarded OGMs
Date: Mon, 12 Mar 2012 16:36:17 +0800	[thread overview]
Message-ID: <201203121636.17494.lindner_marek@yahoo.de> (raw)
In-Reply-To: <CAG7VhQTT-x3WKXahkN5LCbEqFQnhT=0a5ZvX_JA=CRsfS1KdOA@mail.gmail.com>

On Monday, March 12, 2012 16:23:30 Daniele Furlan wrote:
> 2012/3/12 Marek Lindner <lindner_marek@yahoo.de>:
> > On Monday, March 12, 2012 15:49:26 Daniele Furlan wrote:
> >> > I don't quite understand what you are proposing. Are you saying
> >> > removing the averaging mechanism makes this patch obsolete and allows
> >> > replacing the TTL/TQ values as the code does now (without the patch)
> >> > ?
> >> 
> >> No no this patch is good, the removing of TQ average can be a following
> >> step as now average is not forwarded anymore, but only used as a
> >> comparative value between path in another point of the source code.
> > 
> > This follow-up step needs a volunteer. It is a bigger operation to remove
> > the averaging and ensure everything still works.  :-)
> 
> I can try  to send some patch next week to start this operation.. :)

Wow - cool!


> > Do you mind explaining in simple words how the averaging could cause
> > routing havoc together with the strict OGM forwarding patch ? I did not
> > understand. Or are you in favor of removing the averaging for style /
> > performance reasons?
> 
> Actually the average as it is calculated in the current version
> (without "considering" lost OGMs) is not monotonically decreasing. This
> cause routing loops when it is forwarded so with this patch the problem does
> not happen. 

That is what I thought. This patch also enforces monotonicity, thereby 
eliminating the loop "potential" created by averaging the TQ.


> Also maintaing only the latest TQ guarantee to have a more updated
> information about the path. Furthermore an average is already done at
> every link TQ calculation so it is superfluous to have another window.
> This reduce also memory and computational requirements.

Full agreement on this part. 
At the moment, I was more worried about temporary loops which seems to be 
addressed with this patch.

Thanks for all your feedback!

Cheers,
Marek

  reply	other threads:[~2012-03-12  8:36 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-10 22:17 [B.A.T.M.A.N.] [PATCH 1/5] batman-adv: ignore protocol packets if the interface did not enable this protocol Marek Lindner
2012-03-10 22:17 ` [B.A.T.M.A.N.] [PATCH 2/5] batman-adv: refactoring API: find generalized name for bat_ogm_update_mac callback Marek Lindner
2012-03-15  6:44   ` Marek Lindner
2012-03-10 22:17 ` [B.A.T.M.A.N.] [PATCH 3/5] batman-adv: rename sysfs macros to reflect the soft-interface dependency Marek Lindner
2012-03-15  6:46   ` Marek Lindner
2012-03-10 22:17 ` [B.A.T.M.A.N.] [PATCH 4/5] batman-adv: Adding hard_iface specific sysfs wrapper macros for UINT Marek Lindner
2012-03-15  6:48   ` Marek Lindner
2012-03-10 22:17 ` [B.A.T.M.A.N.] [PATCH 5/5] batman-adv: avoid temporary routing loops by being strict on forwarded OGMs Marek Lindner
2012-03-11 21:50   ` Simon Wunderlich
2012-03-12  7:24     ` Daniele Furlan
2012-03-12  7:41       ` Marek Lindner
2012-03-12  7:49         ` Daniele Furlan
2012-03-12  7:55           ` Marek Lindner
2012-03-12  8:23             ` Daniele Furlan
2012-03-12  8:36               ` Marek Lindner [this message]
2012-03-15  6:50   ` Marek Lindner
2012-03-15  6:43 ` [B.A.T.M.A.N.] [PATCH 1/5] batman-adv: ignore protocol packets if the interface did not enable this protocol Marek Lindner

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