Openwrt mt7620n dual SSID implementation principle

For more information, see [Qian guozheng's column http://blog.csdn.net/qianguozheng/article/details/37574373]

Preface

To meet the customer's needs, you need to establish a private SSID and a shared SSID, which requires dual SSID.

Principle

The wireless NIC Driver supports multiple SSID. Different SSID can be used to divide different user ranges. However, the bandwidth and performance of different SSID tests also need to be well studied.

Technical difficulties

It is not difficult to implement multiple SSID, but it is still challenging for a newbie, especially for openwrt on a new platform, the source code of qdk is put on GitHub. This is good, but it is found that the second SSID cannot be started normally during firstboot. This problem exists after any factory reset.

Solution

The analysis shows that the openwrt system starts some processes through/sbin/procd, including init, askfirst, ubus, and ubox, wiFi detect will be included in the script to initialize information related to the wireless driver, and the subsequent done script will contain the link switch2jffs pointing to mount_root, which is compiled from ubox, it is used to mount the root file system/jffs file system, And/ROM is squashfs partition to implement the file system's read and write functions. For the first time, the star switch2jffs may be stuck or the broken script execution process may appear. I cannot fully understand this matter and need further study. I suspect that this process has led to an error when the wireless driver looks for the DAT file or when using it.

Directly create the file/etc/wireless/rt2860/rt2860.dat to achieve this goal. In this way, when the factory settings are restored, the wireless driver will get up.

Unexpected gains

Through this debugging, I found that the Luci page determines whether to display the Wireless Configuration page through the/etc/config/wireless file.

Summary

It took me three days to add the dual SSID. In fact, this problem is not as difficult as I imagined. It is just that the main program or driver dependencies are needed during use, I tried to port the latest openwrt official website about start-up information, but I found it was not feasible. In the end, the console is required when the system is started or when the wireless driver is debugged. Otherwise, it is difficult to identify the problem. I still have a lot of information to see even though I cannot enter it so far.

For more information, see [Qian guozheng's column http://blog.csdn.net/qianguozheng/article/details/37574373]