IP GETS UNREACHABLE IF INTERFACE ADDED TO BRIDGE

RouterOS General
1

Hello Experts,
I’m having an unusual problem on Mikrotik & BDCOM EPON OLT. My goal is to manage connectivity centrally through EoIP. My EoIP tunnel is working smoothly. I have installed a BDCOM OLT in my network. BDCOM is connected to Mikrotik port 2. IP Gateway is on central router’s side (on EoIP tunel, example IP: 192.168.1.1). I’m bridging EoIP tunnel with the BDCOM connected port (Port 2). When I add these two ports to bridge, from gateway to host connected to BDCOM EPON OLT is unreachable (Host IP: 192.168.1.2). If I connect the host directly to Mikrotik’s ether2 (BDCOM connected port) port, the host gets reachable. What I am missing?

Bridge configuration:
name=“bridge-43” mtu=auto actual-mtu=1500 l2mtu=1500 arp=enabled arp-timeout=auto mac-address=64:D1:54:81:EA:6E protocol-mode=none fast-forward=yes igmp-snooping=no auto-mac=yes ageing-time=5m vlan-filtering=no dhcp-snooping=no

Your suggestion is highly appreciated.

2

l2mtu should definitely be higher than 1500 … at least by 18 bytes (which is minimum size of ethernet headers + CRC overhead). And that should be true for bridge and all bridge ports. l2mtu can be different on different links/ports, but have to be big enough to contain full-sized ethernet frame with standard 1500-byte IP packet as payload.

3

Hi mkx
Thanks for your reply. I tried increasing L2MTU. Same result.
Is there any suggestion please?

4

Found the solution. The problem was on the BDCOM EPON OLT. Issuing following command on BDCOM, solved it.

epon local-mac forward
no switchport trunk vlan-untagged