one RB433
3 mikrotik wireless cards
3 sector 120 antenna

I want to make something like an omni 360 antenna:
same SSID on all wireless cards
same frequency on all cards
and no frequency conflict
with roaming capability

whatever setup I test results in something like a loop and there will be no access to MT unless I remove wireless cards!!!

• 1. Define a bridge
  2. Configure all three radios to ap-bridge, same frequency, same SSID, dynamic WDS, with WDS-bridge set to the bridge you just defined
  3. Add all three radios as ports to the bridge

You will end up with CSMA problems if you use the same frequency on all sectors. Use non-overlapping channels for best results. In the USA that's 2412MHz, 2437Mhz, and 2462Mhz.
If you use the same SSID you can have clients choosing which antenna is the best e.g. "Roaming".
For best results when a client hops sectors, use the bridging configuration described above.

If you use different channels, and don't use WDS, doesn't this mean the client has to drop association with the first radio card before it can associate with another? If so, the resulting experience for the user is temporary loss of connectivity (and probably dropped VoIP/streaming media) at each transition.

Which begs the question: is there another way to get radios to hand clients to each other seamlessly, without putting them on the same channel and using WDS?

The Nature of Roaming in 802.11

802.11 roaming is known as "break before make," referring to the requirement that a station serves its association with one AP before creating an association with a new one. This process might seem unintuitive because it introduces the possibility for data loss during roaming, but it facilitates a simpler MAC protocol and radio.

If 802.11 were "make before break," meaning a station could associate to a new AP before disassociating from the old AP, you would need safeguards in the MAC to ensure a loop-free topology. A station connected to the same Layer 2 broadcast domain via simultaneous network connections has the potential to trigger broadcast storms. A "make before break" architecture would necessitate an algorithm such as 802.1D spanning tree to resolve any potential loops, adding overhead to the MAC protocol. In addition, the client radio would have to be capable of listening and communicating on more than one channel at a time, increasing the complexity of the radio (and adding to the overall cost of the devices).

I currently have several multi-radio APs set up as follows:

• 1. Define a bridge
  2. Configure all three radios to ap-bridge, same frequency, same SSID, dynamic WDS, with WDS-bridge set to the bridge you just defined
  3. Add all three radios as ports to the bridge

Now use this three-radio bridge as a single interface, as you would use any other: for DHCP server, hotspot server, etc..

Dan

If I remember correctly, the Mikrotik shows the wireless as being down when there is no one associated to the access point. If you associate to the wireless interface it should show it as enabled.