Re: Critical Mass

Matthew Pitts <daywalker_blade_2004@...>


From what I've been reading on the hsmm-mesh forum, there probably isn't a significant difference between the default olsrd and the one that is a part of the hsmm-mesh firmware. My thoughts at this point would be to use the mesh as primary local transport and have the UDR56K as an interconnection backbone between areas. I am planning some experimentation with a local ham that is interested in hsmm-mesh and will keep the group informed about the potential uses.

Matthew Pitts

Mesh Networking/Self Healing Networks

There have been several people who have talked  about putting HSMM into the UDR56K-4.  I can report that olsrd compiles on the radio's ARM processor but we have not been able to do any testing at this point. I also don't have experience with the HSMM implementation to know if there are incompatibilities with standard OLSR.  This is not a priority for initial release of the radio, however, it would be interesting to have someone in the community provide what differences there might be and possibly take up the port and support of HSMM to the radio.  I have also taken a look at B.A.T.M.A.N. My main question about these protocols is can they scale back to to a 9600-56000 bps CDMA network?  When a protocol assumes a high data rate transport, it just may be too "chatty" for a lower speed network.

Certainly some of these protocols could run on a WiFi dongle attached to the radio, or the radio could be part of the mix via Ethernet or other transport.  I think a self healing network makes a lot of sense, we just have to keep in mind there are always tradeoffs.  With the UDR56K-4 you are trading bandwidth and data rate for power and propagation advantages.  This permits a network to be built with lower density of stations.  The frequency of node beacons needs to be tempered by the speed and number of adjacent nodes -- so a mobile station can run further against a base station before it needs to switch base nodes, but conversely topology updates may be slower.   It may be necessary for inventive hams to build up a light weight protocol that can create a balance between speed and network intelligence. Time will tell, but first we need to get the radio out with stated functionality.

John D. Hays
PO Box 1223, Edmonds, WA 98020-1223 

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