I've faced such problem in 5 Ghz wifi band: deployment of wifi in the company is done with preference to use 5GHz, hence in many sites 2.4 GHz is disabled and wifi is preffered compared to LAN. The problem is that channel amount and channel numbers allowed to be used from country to country is different per political decision. E.g. in Indonesia only following channels are available:
Picture1 - Indonesian allowed channels per WLC's firmware
If we compare this to what is enabled for e.g. Singapore or Thailand we can see only small overlapping subsets of sets of frequencies with Indonesia.
Picture2 - Singaporean allowed channels per WLC's firmware
So WLC in Singapore enables frequencies from this pool then employees from Indonesia with their laptops arrive and cannot see wifi.
The question is: on windows10 possible to change hard-coded "country" parameter in wifi adapter (probably this parameter is hard-coded in EEPROM of computer) or any easier solution to overcome this problem?
That's not how this works: Wireless clients roam all over the world. Those wireless chips should be able to operate at all channels. The APs tell the wireless NICs what channel the AP is operating on. It is up to the wireless NICs to start the authentication process or not.
If the wireless NICs from Singapore is not able to see the SSID then maybe there's fundamentally wrong with the wireless NIC of those laptops? Has any of the Singaporean visitors tried with their personal handheld devices, like tablets or smart phones?
Hold on ... why are the pictures focused on the UNII-3 channels? What about UNII-1?
for Singapore computers all good, its only when Indonesian employees arrive to Singapore they cannot connect (probably they just don't see related SSID, because its broadcasted on Channels which their NIC does not support?!).
why are the pictures focused on the UNII-3 channels? What about UNII-1? - perhaps its hardcoded via firmware: based on my memory, there were more channels before a certain firmware version (which is maybe aligned with indonesian policy for channels).
From the looks of it Indonesia only allows UNII-3 channels in the 5GHz range being 149-161. Now that is only 4 available channels, so make sure that the channel utilization isn't to bad.
As Singapore UNII 3 as well as a number of channels not allowed in Indonesia the should just work when they move to Indonesia.
If they are not seeing the WIFI at all then I would be looking at doing an over the air packet capture and survey work to find out why.
because its broadcasted on Channels which their NIC does not support
No, that's not correct.
WiFi clients support ALL CHANNELS. Period.
APs are mandated by the country to broadcast in different channels. WIFi clients scan ALL CHANNELS.
Just think about it: A wireless client like a laptop is no different to a smart phone or a tablet. These things don't care what country they are in. When the wireless NIC goes up, the first thing it'll do is ask "hey, who's out there" as a broadcast. The APs respond with "SSID: BLAH" and one of the things being sent out is what channel(s) each responding APs are operating on. It is now up to the wireless NIC to make the decision to join which SSID.
So if the Indonesian LAPTOPS can't see the Singaporean SSIDs, then use a tablet or smartphone. I suspect someone has pushed out a group policy update that knackered the channels the Indonesian laptops can operate on. If the personal smartphone or tablet can see the SSID then there's really something "funky" with way the wireless NIC is configured.
Here's another thing: You sure the wireless NIC supports 5.0 Ghz? (I've seen some laptops that only has 2.4 Ghz.)
yes, good link, it shows for Indonesia channels in 5GHz
155, 159, 163, 167, 172
Maybe local government updated policy and shrieked this set to what I've shown on access point?!
I did not see any option in WLC how to enable more channels as it limited per AP's country as I understand.
You would have to make sure the controller has Indonesia as the country code, and the APs are from this regulatory domain.
That being said if they only updated the channels recently there is a potential older APs might not support those channels (may be software or hardware) and you would need to talk to TAC or local Cisco SE.
What are these laptops that are not working? Model, NIC card details?
If you install inssider onto them can you see the SSIDs?
Have you done an Over the Air packet capture to view what the supported channels on the laptops actual are and what is being broadcast from the APs.
has a client debug been conducted when the client is attempting to associate to the wireless been done? If so please share.