Hi, i have some updates.
I tested passthrouth ICMP packet and PVST+ frames between CE switches.
ICMP:
CE1 -- ICMP (C-VLAN10) -> EX3400 -> ICMP (C-VLAN10, S-VLAN100) -> EX3400 -> ICMP (C-VLAN10) -- CE2
It works well, same as another L3 traffic.
PVST+
CE1 -- PVST+ (C-VLAN10) -> EX3400 -> PVST+ (S-VLAN) -> EX3400 -> PVST+ (NO VLAN TAG) -- CE2
EX3400 strip C-VLAN tag on input interface from PVST+ frames!
Its look like EX3400 strip VLAN tag from PVST+ (the same behavior for VSTP) on QinQ customer interface.
I think this is some kind of bug, because on EX2200 or EX4200 it does not happen.
Thx