Can anyone assist with instructions on how to establish a 3-way bridge between three buildings using three Mikrotik 911G-5HPacD devices.

I have had great success running a PtoP bridge between two buildings for a number of months, but we have an urgent need to extend the network to a third building.

I will be ordering more equipment to implement a second PtoP link, but until that happens, I was hoping to build a three-way bridge.

I have the third Milrotik in place, and am able to get either one of the CPE devices to communicate with the AP, but I can't seem to get them sharing a connection art hte same time.

Both devices are in station-bridge mode, and I have tried both nstreme and NV2 protocols without success.

Any suggestions would be greatly appreciated.

I'm sure I have overlooked something fairly simple, but I am stumped at the moment.

One of them must be in AP Bridge and the others must be in Station Bridge and will connect to the AP Bridge.

I finally managed to get them both connected to the AP by manipulating WDS and AP/client settings.

I also switched to NV2 protocal rather than nstreme.

Although user devices can communicate over the three way bridge, there is still something not quite right, as I often find that I can only connect to one of the remote Mikrotik devices at a time.

by manipulating WDS and AP/client settings...

This "manipulating" might be the reason.

I finally managed to get them both connected to the AP by manipulating WDS and AP/client settings.

I also switched to NV2 protocal rather than nstreme.

Although user devices can communicate over the three way bridge, there is still something not quite right, as I often find that I can only connect to one of the remote Mikrotik devices at a time.

At all 3 sites, there should be a bridge interface - e.g. bridge1
At all 3 sites, the IP address for this bridged network should be applied to the bridge1 interface (not the wlan interfaces)
At all 3 sites, connect the wlan interface and at least one ethernet interface to the bridge1 bridge.

At the AP, the mode should be standard "ap bridge" mode, and in the WDS tab, mode should be dynamic and bridge = bridge1.

At the stations, the mode should be station wds.

On the AP, whenever a station connects, you should see a dynamically-created WDS interface appear, and it should be listed in bridge ports as a member of bridge1. If you look in the hosts tab of the bridge at the AP, the MAC addresses of LAN hosts at the two remote sites should appear to be on the dynamic WDS ports.

Make sure that each Mikrotik has a unique MAC address on its bridge1 interface, because this could be the reason you're getting intermittent pings. Also make sure that each has a unique IP address on the bridge interface.

Zerobyte... thanks for the thoughtful and detailed reply!

One detail I may not have been clear about is that the only wireless devices in play are the three Mikrotiks.

Client devices behind the MikroTik radios are wired devices.

In light of that, is WDS a required part of the setup, or can the configuration be simplified?

Also, if there is relevant documentation in the Wiki or elsewhere that someone could point me toward, that would help me wrap my head around some of the bridging options that Zerobyte pointed out.

I'm a little wary of experimenting too much on a live link... don't want to risk breaking anything, even if it is mostly held together with "beginner twine".

In light of that, is WDS a required part of the setup, or can the configuration be simplified?

Honestly, it's very simple. You would already need to create bridge interfaces at all locations anyway. The only added "complexity" of wds is turning it on at the AP and setting the clients to use station-wds (instead of plain-vanilla station mode),

WDS is completely required if you want to transparently bridge any ethernet segments using wireless. (well, Mikrotik has a proprietary bridge mode as well, but this is strictly for a point-to-point, where WDS works for P2P or P2MP just as easily.)

The reason you need WDS is that normally, only the wireless stations' MAC addresses will appear on the wlan. If you need to bridge a wired client onto the wlan, and you need the client's MAC address to appear on the wlan - well, you technically can't do it. What wds does is create a sort of "tunnel" across the wlan between the access point and the station.

The AP will dynamically add these tunnels to the bridge as if they were extra ethernet interfaces.

At that point, it's just normal bridging on the AP's side - bridging between the ethernet interfaces and the wds interfaces.

FYI: WiFi extenders work by using their own MAC address when repeating traffic to the access point - this is okay for end stations, but if you tried to put a non-NAT router behind an extender (for example) it wouldn't work.

If the AP has a Level 4 licence then set it to 'AP Bridge' mode and all the clients are set to 'Station Bridge' mode, you can have almost as many devices connected as you wish. No need for WDS at all. This is how we run PPPoE through to our customer's routers in our WISP. One Radio in AP Bridge, all the customers in Station Bridge mode. A totally transparent L2 network between our Base Station MikroTik and Customers' MikroTiks.

If the AP has a Level 4 licence then set it to 'AP Bridge' mode and all the clients are set to 'Station Bridge' mode, you can have almost as many devices connected as you wish.

I thought that mode was just for P2P links. Interesting.

Bridge -> Station Bridge is for ptp
In bridge mode only one station can connect.

p2p - peer to peer
ptp - point to point

As InoX states, 'Bridge' mode only allows Point to Point connections. But there is also 'AP Bridge' mode. It allows multiple connections and the interfaces are bridged on L2 if also using 'Station Bridge' mode on clients.