I use Microtik APs to create a continuous Wi-Fi network (with overlapping cells) in underground mines. This unique topology has numerous L2 switches serially inter-connected, with a Microtik APs connected to each of these serially inter-connected L2 switches. When a client roams to a new AP it is critical to update the MAC address to port number mappings in all of the serially inter-connected switches to avoid drop-outs of real-time traffic (specifically remote control of unmanned vehicles).
From my initial tests with Microtik equipment it does not handle this scenario well.
[] The first problem was the fact that default bridge settings have RSTP enabled. Once this is set to None, packet flow after roaming occurs a lot faster.
[] The second problem is that Microtik AP firmware does not send out a L2 broadcast on the Ethernet interface on behalf of each new client after they associate. This broadcast on the Ethernet interface is implemented by other vendors typically as an LLC RNR or XID packet, but with the source address being the new station’s MAC address.
It would be great if the Microtik engineers could add this capability to a future firmware update, as it is important to send this LLC RNR packet out as fast as possible after the new association. In the interim, I have created a script that runs on each of the APs, which is scheduled to run at startup. This script “follows” the registration-table and sends out the LLC RNR packet whenever a new client associates, thus updating the upstream switch MAC address tables.
However, it is not particularly efficient as a script so having it built into the firmware would be better.
If anybody else has a similar scenario, I’d be keen to understand how they have solved it with Microtik APs.