open 80211s on XO 1.5

Ed McNierney ed at
Fri Oct 30 15:50:17 EDT 2009

On Oct 30, 2009, at 3:32 PM, Sameer Verma wrote:

>  scenarios of a handful of XOs in the under-a-tree model

Sameer -

Under a tree, using mesh networking is pointless (unless, I suppose,  
it is an extraordinarily large tree).  Mesh networking allows packet  
forwarding from node A to node B, where such nodes cannot normally  
communicate with one another directly.  Packets are forwarded through  
node C, visible to both A and B, or through multiple such intermediate  
nodes.  If A can communicate with B, mesh is neither helpful nor  
advisable.  It just confuses things, which is the problem we see with  
large numbers of children in a classroom.  The mesh efforts to keep  
track of how to get from A to B can quickly saturate the RF spectrum  
with a lot of unhelpful traffic.

I can't tell what it is you're doing at your meetings when your users  
"all use mesh".  At a typical in-person meeting, you have a number of  
people using XOs all in the same room.  Any XO in the room can  
communicate over WiFi directly with every other machine in the room  
(except in extremely unusual circumstances, or too many attendees  
wearing their tinfoil hats).  There's no need for or value to mesh  
network - A doesn't need C to forward packets to B because A can see B  
directly as another ad hoc node.

If there's an AP providing routing to the Internet or other external  
networks, there's no mesh required there, either, presuming that each  
XO can communicate with the AP directly.

I can't answer your question about whether those scenarios use ad hoc  
networking because I don't quite see what it is the users are doing in  
those scenarios.  What (lowercase) activity are users engaged in when  
you say they "all use mesh"?  What do you think they would be unable  
to do if they all stopped using mesh?  Thanks for the info.

	- Ed

More information about the Devel mailing list