ESP8266 Community Forum

- Wed Sep 24, 2014 6:25 pm #892 Ad Hoc can hook to an arbitrary number of random nodes without needing to be set up. With AP/STA you will need to manually construct the mesh and authorize each pair. I also believe ESP8266 only supports a single STA while in AP mode. If nodes are moved Ad Hoc can automatically repair, AP/STA will need adjustment. So it is possible to build a mesh on AP/STA but it is not recommended. Almost all wifi networks running the BATMAN protocol use Adhoc mode for mesh traffic.

It is also likely that the node will run all three modes - Adhoc, AP, STA. STA hooks to an Internet router if available. AP is for normal PC/tablets. Adhoc is for mesh traffic. This is a common BATMAN configuration and why most people use the AR9331 for BATMAN meshes. Many wifi chips can't run all three simultaneously and AR9331 is one of the few that can. RT5350 cannot so that's why you don't see it used in mesh nodes.

Running all three modes is a lot for a tiny chip like an ESP8266. So in a mesh I'd expect it to only run Adhoc mode and not function as a main routing node. This is another area where mixing chips makes sense. Build larger nodes using the AR9331 and then make mesh only nodes using the ESP8266. TL-WR703N is a very popular AR9331 router - $20.

BATMAN is used a lot since it will route across mixed networks - ie wired links between nodes are allowed. The links have different weights and BATMAN will preferentially use the wired links. A few strategic wired links makes large, campus wide BATMAN networks possible.

http://www.open-mesh.org/projects/open-mesh/wiki

Where I get my modules

- Wed Sep 24, 2014 6:53 pm #894

Ad Hoc can hook to an arbitrary number of random nodes without needing to be set up. With AP/STA you will need to manually construct the mesh and authorize each pair.

Well the data sheet lists mesh networks and WiFi direct. But with AP/STA you could still approximate a mesh by having each STA connect to the AP with the highest RSSI and a route to the master. Implement healing/optimization as necessary. More like a chain than a true mesh I guess.

- Wed Sep 24, 2014 7:18 pm #897 WifiDirect is supposed to be some new PTP wifi mode. I don't know anyone who has played around with it for meshing purposes. The main use case for it is doing something like using a printer from a phone without logging into an AP. To my limited understanding WifiDirect just looks like sugarcoated soft AP.

I Googled around for a few minutes and can't find anyone with a working mesh on top of WifiDirect.

BTW - that source code for the Rockchip ESP8089 driver may contain enough info to get Adhoc mode working on the ESP8266.

Also - people don't like the STA/AP chain topology since it is fragile. It is too easy to break things to where you need to physically access the broken node in the chain to fix things.

Last edited by jonsmirl on Thu Sep 25, 2014 6:07 am, edited 1 time in total.

Where I get my modules

- Wed Sep 24, 2014 7:54 pm #899 WiFi direct does support groups, but I'm not familiar with the details.

AP/STA has its drawbacks, but is probably adequate for many situations.