Hi Marek,

Thank you for your help, as I did not subscribe to the mailing list, I did not get your reply. I subscribe to the mailing list now and I am writing a new email thread.

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We have been building openwrt 15.05 + batman-adv mesh network for over 2 years, they work great.

hopefully, the batman-adv version you are using is newer than 15.05 ...

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1. My first thought is to use batman-adv gateway (with 4G modem

connected) as dhcp server, and forward batman-adv interface to wan interface (modem).

1.1)  But, there is an issue with this setup. Once a modem is down, nodes that are connected to this batman-adv gateway (with modem) can not automatically "roam" to another batman-adv gateway (with good modem connection).

Why not ? What should prevent nodes or clients to choose another

batman-adv

gateway ?

When modem (for WAN uplink) at gateway is down and loses internet connection (but batman-adv connections with clients are good and dhcp server works good), can batman-adv clients know that internet connection at gateway is lost and "roam" to another gateway with good internet connection?

Thanks. Xuebing Wang