v6.41rc1+ bridges and broadcast

RouterOS Beginner Basics
1

Good day forum!
Sorry for maybe newbie question but i need to know how some stuff works:

As documentation says : When a switch receives a broadcast, it forwards it to each port on the switch except the incoming port.
Does new Mikrotik bridge replacement for switch chips do the same or i need to write filter rule to prevent source MAC broadcast packet flooding back?

2

I haven’t tested it myself, but I am pretty sure that it will work this way. These are pretty standard stuff for MikroTik to have overlooked.

3

Ok, i done some experiments and find that broadcast packet returned thru source interface and caused an loop in the neigbor device… Maybe i don’t understand new bridge well?

4

Any comments from MikroTik?

5

It would help if you post your config. Or send a support request to Mikrotik.

6

Config is simple.
sfp1 - Goes to provider device.
ether2, ether3, ether4 - customer devices (routers).

/interface bridge
add fast-forward=no name=main1 vlan-filtering=yes

/interface bridge port
add bridge=main1 interface=sfp1
add bridge=main1 interface=ether2 pvid=2
add bridge=main1 interface=ether4 pvid=3
add bridge=main1 interface=ether3 pvid=4

/interface bridge vlan
add bridge=main1 tagged=sfp1,ether2 vlan-ids=2
add bridge=main1 tagged=sfp1,ether4 vlan-ids=3
add bridge=main1 tagged=sfp1,ether3 vlan-ids=4

Problem is: broadcast packet from sfp1 with mac 12:34:56:78:9A:BC goes back in sfp1 causing loop in provider device…
What i’m missing?

7

It might be bad optical cable connection. What errors do you receive on sfp port in “Traffic” tab?

8
  1. There no issues with optical connection, tested with other switches.
  2. As i have written - there is no errors in Mikrotik itself, broadcast packet just returns thru source interface back to sender causing broadcast storm.
  3. All connected devices are OK and tested with Cisco and Extreme switches.