My goal is for two or more devices (incidentally LinkIt Smart 7688s) to communicate over WiFi in a field situation where there is no access point such as a Wifi router. It's preferable that all devices are "peers", i.e. I'd prefer there not be one "special" device that acts as an "Access Point" for the others. Also preferable that no DHCP server is required.
I've configured the devices for an Ad Hoc networking with link local addresses. I run the same commands on each device except that I bump the last number in the ip for each.
modprobe mt7603e iwconfig wlan0 mode ad-hoc channel 11 essid my-network ifconfig wlan0 up 169.254.0.2 netmask 255.255.0.0 # In above commend I replaced 169.254.0.2 with 169.254.0.3 on 2nd device
They appear to join the same network, the first device reports:
wlan0: Creating new IBSS network, BSSID 2a:fa:72:1d:eb:56
And the second device reports:
wlan0: Selected IBSS BSSID 2a:fa:72:1d:eb:56 based on configured SSID
Note that the second device appears to have "selected" the network that the first device created.
I thought this looked promising, however trying to ping one device from the other fails:
ping 169.254.0.2 PING 169.254.0.2 (169.254.0.2) 56(84) bytes of data. From 169.254.0.3 icmp_seq=1 Destination Host Unreachable From 169.254.0.3 icmp_seq=2 Destination Host Unreachable
One device cannot ping the other. Incidentally each device can ping its own ip successfully.
I'm running a custom Linux created using Build Root so I don't necessarily have access to all the tools you would get on a more standard Linux install but I have or can get many of the common ones.
Thanks so much for reading. I'd really appreciate any suggestions for troubleshooting this!
For what it's worth here is the output of
iwconfig, this is from one device, the other device reports identical results aside form ips and mac addresses. I checked both and the
Cell that's output in
iwconfig is the same for both:
# ifconfig lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:20 errors:0 dropped:0 overruns:0 frame:0 TX packets:20 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1 RX bytes:1515 (1.4 KiB) TX bytes:1515 (1.4 KiB) wlan0 Link encap:Ethernet HWaddr 9C:65:F9:1B:83:99 inet addr:169.254.0.3 Bcast:169.254.255.255 Mask:255.255.0.0 inet6 addr: fe80::9e65:f9ff:fe1b:8399/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:0 errors:0 dropped:0 overruns:0 frame:0 TX packets:14 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:0 (0.0 B) TX bytes:1152 (1.1 KiB) # iwconfig lo no wireless extensions. wlan0 IEEE 802.11 ESSID:"my-network" Mode:Ad-Hoc Frequency:2.462 GHz Cell: 2A:FA:72:1D:EB:56 Retry short limit:7 RTS thr:off Fragment thr:off Encryption key:off Power Management:off eth0 no wireless extensions.
Update: In addition, here is the output from
ip route show:
# ip route show 169.254.0.0/16 dev wlan0 proto kernel scope link src 169.254.0.3