On 5 Feb 2007 05:51:05 -0800, "Karen" <(E-Mail Removed)> wrote in
<(E-Mail Removed) .com>:
>My understanding is that this is wireless from person to person,
>rather than from street corners, etc. I've signed to their mailing
>list.
>
>http://meraki.net/
>
>Meraki is coming.
>And we're bringing the Internet with us. We've developed a way to
>provide free or affordable access to the next billion people.
>
>We'll be ready to share with everyone very soon. You can sign up
>below
>to find out when we launch. Early adopters familiar with Meraki can
>still e-mail us to join the beta for $49.
$49 isn't "free".
"If it sounds too good to be true, it probably is."
Meraki is "a Wi-Fi network that is not top-down but rather ground-level,
peer-to-peer." In other words, a chaotic ad hoc mesh network, a truly
horrid idea. See
<http://www.dailywireless.org/2004/06/28/ugly-truth-about-mesh-networks/>
Ugly truths about mesh networks - they dont scale - for now.
by Francis daCosta
As founder and CTO of a Wireless Mesh networking company, I have
pondered long and hard about whether or not I should submit this.
The buzz on mesh networking certainly works in our favor. However,
there is more hype than reality around mesh networking. Its time for
a reality check on what mesh can and cannot do.
First, Mesh networks are not a new concept. In some ways, the
internet is a mesh network. And it works, despite its size - because
it does not suffer from the limitations of conventional wireless mesh
networks:
1- Radio is a shared medium and forces everyone to stay silent while
one person holds the stage. Wired networks, on the other hand, can
and do hold multiple simultaneous conversations.
2- In a single radio ad hoc mesh network, the best you can do is
(1/2)^^n at each hop. So in a multi hop mesh network, the Max
available bandwidth available to you degrades at the rate of 1/2,
1/4, 1/8. By the time you are 4 hops away the max you can get is 1/16
of the total available bandwidth.
3- That does not sound too bad when you are putting together a
wireless sensor network with limited bandwidth and latency
considerations. It is DISASTROUS if you wish to provide the level of
latency/throughput people are accustomed to with their wired
networks. Consider the case of just 10 client stations at each node
of a 4 hop mesh network. The clients at the last rung will receive
-at best- 1/(16,0000) of the total bandwidth at the root.
4- Why has this not been noticed as yet? Because first there are not
a lot of mesh networks around and second, they have not been tested
under high usage situations. Browsing and email don t count. Try
video - where both latency and bandwidth matter - or VOIP where the
bandwidth is a measly 64Kbps but where latency matters. Even in a
simple 4 hop ad hoc mesh network with 10 clients, VOIP phones wont
work well beyond the first or second hop the latency and jitter
caused by CSMA/CA contention windows (how wireless systems avoid
collisions) will be unbearable.
Mesh networks are a great concept. But the challenge lies in managing
the dynamics of mesh networks so users receive an acceptable level of
performance in terms of both latency and throughput.
Its time to focus on solving some real problems to make mesh networks
scale and provide stable performance.
--
Best regards, FAQ for Wireless Internet: <http://Wireless.wikia.com>
John Navas FAQ for Wi-Fi: <http://wireless.wikia.com/wiki/Wi-Fi>
Wi-Fi How To: <http://wireless.wikia.com/wiki/Wi-Fi_HowTo>
Fixes to Wi-Fi Problems: <http://wireless.wikia.com/wiki/Wi-Fi_Fixes>
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