I configured br1 to the @Peter Havekes practice from https://www.snbforums.com/threads/ipv6-for-guest-network.30787/
And used tcpdump to capture packages on the ppp0.
These packages were sent out and responsed remotely.
It may be that I used the same network segment in br1 and br0 to cause routing problems, and finally make these package not successfully forwarded to the device.
The IPv6 is set native mode and the mask length on ppp0 and br0 are 64 and 60, respectively.
May I use a script to apply for a new network segment to br1 from the ISP, or separate the network segment of the br0 into two small network segments.
And used tcpdump to capture packages on the ppp0.
These packages were sent out and responsed remotely.
It may be that I used the same network segment in br1 and br0 to cause routing problems, and finally make these package not successfully forwarded to the device.
The IPv6 is set native mode and the mask length on ppp0 and br0 are 64 and 60, respectively.
May I use a script to apply for a new network segment to br1 from the ISP, or separate the network segment of the br0 into two small network segments.