[OLPC Networking] Mesh network?

Krishna Sankar (ksankar) ksankar at cisco.com
Wed Sep 6 17:03:33 EDT 2006

As usual, excellent questions & insights. Actually these need to go in
the Wiki.
a)    802.11s support (hardware and device drivers) will be built by

b)    I haven't had the exposure to see if it will support 802.11(a/b/g)
as well. We also need to check if the modes can be switched without a

c)    Things like multiple heterogeneous connections are the "magic", to
happen in the OLPC version of the network manager 

d)    Load balancing across multiple heterogeneous connections is a good
idea, am not sure it can be done even now.

e)    Most probably the laptops will support infrastructure 802.11g as
well as ad-hoc mode, but not simultaneously to act as a rely.

f)	Naturally, the first version will have constrained capabilities,
which will improve as we understand more about the
topology/interference/power requirements and their interactions in the
OLPC scenario i.e. the software that runs on the network substrate. 

g)	Many of the mesh features and network protocol switching will be
controllable by software; thus leaving the hardware/firmware/drivers to
optimize to the max, under normal circumstances. 

	We cannot add networking features with reckless abandonment, as
we are constrained by power and maximize functionality with minimum
power. Hence many cautionary e-mails, on the protocols, message
exchanges et al.

All in all, exciting times are ahead !



	From: MBurns [mailto:maburns at gmail.com] 
	Sent: Wednesday, September 06, 2006 1:43 PM
	To: Krishna Sankar (ksankar); networking at laptop.org
	Subject: Re: [OLPC Networking] Mesh network?

	On 9/6/06, Krishna Sankar (ksankar) <ksankar at cisco.com> wrote: 

		        c)    The mesh (802.11s) will be implemented as
a Layer1/L2 artifact

	Nice. This was what I was looking for. Does anyone know on how
well/if at all  802.11s is supported in the wild thus far? Is it
something the OLPC will be building into the networking stack from the
ground up, or is the heavy moving already done? 
	With regards to an Internet access. I assume that a laptop
plugged in to, say, a modem, or some type of wired connection would
seemlessly (auto-magically?) announce/forward that connection to other
laptops on the ad hoc mesh? Is the idea of 2 different laptops, each
with 2 different connections (1 broadband, 1 narrowband connection) both
on the same mesh? Would they both share connectivity, and if so, would
we be providing metrics to choose best route or load balancing? 
	Finally, will a laptop be able to be on a wireless LAN (802.11g
network) and also be able to share/relay that connection to other
laptops (that might be out of range of the .11g network). That is to
say, can we virtualize our wireless nic so as to be on two networks at
once, etc. 
	Lots of questions and few answers, no doubt. But this is the
place to ask. :)
	Michael Burns
	Network Engineering
	Oregon State University

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