[Cerowrt-devel] [Babel-users] switching cerowrt to quagga-babeld issues
dpreed at reed.com
dpreed at reed.com
Thu Jul 5 10:15:02 EDT 2012
Regarding radio benchmarking, note that the effect of the surface of the dirt/vegetation below line of sight seriously affects 2.4 and 5 GHz. It's been measured and reported (forget which journal) by folks from Berkeley who just did some empirical studies. E.g. 6 inch vs 11 inch grass 5 feet below the antenna makes a big difference, etc.
On the other hand, you know that in the real world, lab benchmarks of radios mean nothing at all, especially in a protocol based on contention where the energy in the beginning of the packet is crucial, independent of the decodability of the bits, but the decodability of the bits affects the backoff, etc.
I would suggest that tests that matter will be carried out in the densely populated worlds of cities, towns, ... If a mesh cannot survive in that environment, it's going to be of very, very limited usefulness, other than to provide Ph.D. dissertations in "optimal" routing in *imaginary* conditions.
Forget "optimal". Stable, scalable, resilient, simple, and good enough is far more important, practically.
From: "Denis Ovsienko" <infrastation at yandex.ru>
Sent: Wednesday, July 4, 2012 7:34am
To: "cerowrt-devel" <cerowrt-devel at lists.bufferbloat.net>
Subject: Re: [Cerowrt-devel] [Babel-users] switching cerowrt to quagga-babeld issues
>> The project may get more options, if we drive the prototype towards a finished deliverable.
> I am very enthusiastic about babel's new authenticated mesh routing!
> It is also my opinion that without a decent drop and packet mixing
> strategy that mesh networks will perform badly under load. I'm hoping
> that fq_codel does well, although it seems very likely that an
> aggregation aware and fq_codel-like strategy needs to move into the
> mac80211 layer, which is perhaps years worth of work.
> What would a deliverable look like? What would interest people enough
> to get some good data, papers written, progress made, more
> users/developers and cash in the door?
Considering CeroWrt as a free software project, it may be the right time to measure each of the following:
1. Amount of manpower/cash required to keep the project afloat and developing.
2. Added value, which exists due to its unique properties.
3. Population of developers willing to invest their manpower/cash.
4. Population of users willing to use the outcomes as long as it helps them stay focused on their own needs.
Accounting and distributing CeroWrt daily duties will make some space for a day job, at least part-time, which is very important. Focusing the 2nd item to help users understand the point of switching a Netgear box to CeroWrt will help the community grow naturally. The deliverable could come like this:
"Here is a small automatic test, which will measure the jitter, delay and RTT of your connection through a Netgear box to a server far on the Internet. Record these numbers and repeat the test after flashing the 3800 with this stable CeroWrt release. Let us know the difference and consider these unique features, which are available in CeroWrt only:
* something good
* something else
> I presently have 4 Nanostation M5, 3 picostation HP, and 5 wndr3700s.
> I've found a good site to work with 2.4ghz and 5.x ghz radios (a 110
> acre campground that has given me permission to play here) and test
> fq_codel in various forms of cerowrt in, for as long as I like.
> One of the things we've really struggled with was in today's saturated
> 2.4ghz environment there is no way to benchmark both radios. We've
> been reduced to suggesting we 'flee to the mountains' in order to get
> good results. OK, I just did that.
Picking some antenna types other than omnidirectional may be another solution, but it depends.
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