Wi-Fi issues (5 routers with same SSID, machine keeps switching routers)

Question

I'm using a city wide Wi-Fi. It's really good, but I don't know where the routers actually are.

The problem is that my Mac OS X Lion machine shows all bars for this network's SSID and some of the routers are actually closer than the others and behave differently.

One router gives me consistent 30ms ping, and stable connectivity. Other routers give me 250ms ping and dropped packets. The network still shows at all bars on my computer for that SSID, but in reality there are multiple routers with different signal strength that my computer doesn't know the difference between because they are all the same network with the same SSID.

Is there a way from my machine to get the MAC address of one of the routers and get fixed to that? Or maybe with a more specific application be able to see all of the broadcasting devices on that network so at least I can know which one is giving me the best and worst signal strength (for when I call the company that runs the network)?

Answer 1

Since OS X is a unix derivative, it should have iwconfig or a similar tool available.

Found this (with Google)

I am not a mac user though, so I can't provide more specific instructions. However, this should be enough to get you started.

Answer 2

There is no functionality for fixing your machine to a particular base station if they share the same SSID; it's automatic, based on whichever has the strongest signal.

You would be able to get the router's MAC address via a tool like Wireshark; while connected, start a capture of the airport interface and look for traffic to/from your route. Look through the packets captured and you should see something like Address: Apple_36:d2:43 (00:24:36:36:d2:43) for a source or destination, depending on which way the packet was headed.

If you want to see more in Wireshark than just traffic between your system and the base station:

Capture -> Interfaces -> Click on "options" next to interface with radio tower symbol -> "Capture packets in monitor mode"

That will show beacon frames and more, complete with MAC addresses, from anything within signal range. To see the originating MAC address, select a packet, expand the line that starts with "IEEE 802.11 Beacon frame",