Hi, Marco Bob has given you good comments.
AFAIK, Atheros chipset that uses ath9k driver should able to run "iw meshX survey dump". ---- Chun-Yeow On Wed, Jan 21, 2015 at 11:09 PM, Bob Copeland <[email protected]> wrote: > On Wed, Jan 21, 2015 at 11:28:32AM +0000, Steger, Marco via Devel wrote: >> Are there any parameters which will change while I'm increasing the >> distance between the two nodes? Bit rate? Anything else? Any parameter >> which can probably change? (I really want to have a clear and proper >> result) > > You can expect rate to decrease as distance increases. In practice, > it's difficult to control for the channel conditions in such an experiment, > because small movements may cause large changes in the channel properties. > >> To get the packet error rate I want to periodically/permanently send >> message from one node to the other one. Can I use normal UDP packets >> for that? Is there a possibility to send packets on a lower layer in >> Linux? (I think raw Ethernet sockets will be helpful but I will have >> to investigate some more here) > > You may wish to distinguish (layer 3) packet loss and (layer 2) frame loss. > The frame loss is probably the more interesting number... for that I > believe there are some counters you can use that are exported in debugfs. > > Note that for unicast traffic over wifi, there is a retry mechanism at > the MAC layer, so some levels of frame loss may not show up as UDP packet > loss but as latency instead. > > For multicast traffic, there's no retry, but there's also no rate > scaling. > > Relevant to mesh: besides channel conditions, latency and bandwidth are > also determined by the number of nodes that are communicating, because > only one station in a given listening area can transmit at a time. So > consider that in a 3-node, multihop scenario (A<->B<->C), you'll probably > see a factor of 2 reduction in achievable throughput compared to just two > nodes. > > -- > Bob Copeland %% http://bobcopeland.com/ _______________________________________________ Devel mailing list [email protected] http://lists.open80211s.org/cgi-bin/mailman/listinfo/devel
