I've five custom ethernet switch device in my network (custom ethernet switch include stm32+microchip ethernet switch). They have RSTP protocole and blocking loops perfectly. But when I connect the device cascad my connection like this PC-SW1-SW2(RootBridge)-SW3-SW4-SW5, when I start to ping my device SW3 not pinging SW4-SW1-SW5 pinging successfully but after the Root Bridge device I could not ping. When I disable the RSTP on my switch they communicate successfully. How could I found my problem, I check between SW1 and SW2 device SW1 route all ping to SW2, but SW2 couldnt forward SW3's ICMP and ARP packets. What is the reason for anybody have an idea?