I have encountered a problem that has also been reported by many Netizens that they have experienced an annoyingly (some called it obscenely) long time to connect to their WiFi network when their Windows is woken from sleep. My laptop is running Windows 7 with all drivers up to date.
In my case, all WiFi connections are flagged 'Automatically Connect' and that the WiFi adapter did not have the "Allow the computer to turn off to save power" in the power management section selected.
When I wake my laptop up from sleep, the machine responses very swiftly and my desktop is restored. However, it frequently fails to automatically connected to the strongest signal WiFi nor initiates any attempt to connect; I have to manually press the connect button.
I have tested my machine with two distinctively different Wireless networks - different modems/routers and networking technologies and I have observed the same problem. Hence it is clearly the problem is in my laptop.
Prior to last month, my laptop's WiFi adapter connects to the network the moment I sign in after waking my machine up (< 10 seconds). Then suddenly the about mentioned problem occurs.
After some soul searching and searching the Internet, I have managed to rid this problem restoring it to its former glory. I am not suggestion nor recommending my way of solving my problem as a solution to deal with all long connection problems but you many review the materials to see if it can apply to your situation. It does not involve some drastic proposal found on the Net. IPv6 has nothing to do with this sluggish behaviour.
So what is the possible cause then? After some soul searching of what I did to my machine, I vaguely remember one evening I was investigating the Virtual WiFi Router that turns your laptop's WiFi Adapter into a wireless access point and that to understand the underlying mechanism, I was using the command line technique. In that experiment, I vaguely remember that I did not complete the whole process as I do not have a real need of it and that I might even have gotten the command sequence out of whack.
That experiment caused the "Microsoft Virtual WiFi Miniport Adapter" to appear in my Device Manager, albeit with a yellow triangle with an exclamation mark in it.
This gives me a clue that it might (just a might) be the cause of my problem - I therefore may have to disable or remove the miniport. So after some research, I have found the following instructions to disable the "Microsoft Virtual WiFi Miniport Adapter" and here are the steps (must be executed in a command prompt with Administrative rights):
1) To stop the hosted network
netsh wlan stop hostednetwork
2) To disable the WiFi Virtual Adapter
netsh wlan set hostednetwork mode=disallow
I throw in a Windows restart just for the safe measure. After that the long process connecting to the WiFi network is gone and the machine is restored to its former behaviour on waking from sleep; no longer do I need to manually click on a Wireless network to connect to it.
You can find more information on the netsh command to deal with the wireless hosted network on the Microsoft's site here.
Once I have executed the above mentioned commands, the "Microsoft Virtual WiFi miniport adapter" disappears from the Device Manager.
If you have used or experimenting with the Microsoft's virtual wifi hotspot (or router), a good sign is the presence of this adapter in the Device Manager, give this a try and see if it helps.