pppoe router on a stick error！！！

RouterOS General
1

My ros only have one single network port(eth1 rename to wan)。A.I want ros to pppoe dial-up。B.ros send lan data to modwan C.eth1 not only for wan feature but also have lan feature.
Can you help me how to send lan data to modem.
A.pppoe:
(1)eth1 receive vlan8 data(from a modem) in eth1.
(2)I create a vlan8 interface in eth1。
(3)create a pppoe with vlan8 interface。
(4)all is ok.
B.lan data
(1)eth1 reveive untag data(from a modem,use this data is lan data) in eth1.
(2)I create a brige1(it is a brige interface) open vlan filtering(pvid 1),i think ros transform untag lan data to vlan 1 data in ros(pvid feature).
(3)ros defalut add eth1 vlan1 untag port(ros transform vlan 1 data to untag datag,untag port feature)
(4)i set vlan8 in eth1 tag port.
(5)i think all ting is ok. but i have broadcast storm。！！！！！

2

Your photographs of screen are unreadable to me, so they don’t help.

But conceptually:
A.pppoe seems fine to me

B.lan data: you’re overthinking. Simply use ether1 as base for LAN IP settings

But: are you sure your modem supports this kind of hybrid port usage?

3

B.I only want use one port for lan and wan.I am sure my modem support this hybrid port.

4

How do you want to connect more than one device to one ETH port with one cable? Can you explain this phenomena?

5

Q:Why we must used one port.
A:modem only one port is 2.5G port. if we used this port for wan and lan.we will get more 1G speed。

Q:Why we must push lan data to modem.
A:my modem is a FTTR deivce.if we not push lan data to modem. mesh node will not to used.