Are all machines on a multiple-AP wifi network visible to one another?

Question

I understand the basic principle of a wifi network with multiple access points. As long as each AP has the same SSID, passphrase and encryption method, my devices will switch between access points as I move around the house.

This is commonly explained in the context of internet connectivity for a single roaming device. For example, when I move my laptop from one side of the house to another, I don't lose my internet connection and I don't need to switch networks / APs.

But I want more than just internet connectivity for individual devices. I want to be able to access devices across the network, including when they have switched access point. For example, sshing onto a device, or accessing its web interface.

Consider the following example:

• Wired device 1 connected to router
• Wireless device 2 connected to router
• Wireless device 3 connected to extender

Can devices 1, 2, 3 connect to each other, to the router and to the extender? Can they retain this connection if device 3 roams between access points?

Answer 1

Yes, plain access points are bridges. Unless configured otherwise, they will pass all Ethernet frames from any host to any host (as well as between any wireless host and any wired port), creating one subnet the same way that Ethernet switches do.

(If this doesn't work, make sure your APs didn't come with "Client Isolation" enabled.)

However, some people (and especially some manufacturers) define 'access point' as also including a router. While devices can reach each other through a router or several, it's not something that works by default in both directions (it requires route configuration) and it's incompatible with automatic Wi-Fi roaming (due to requiring a different subnet for each router). Make sure your APs are specifically set to 'bridge' mode.