Same SSID for both 2.4 and 5GHz bands?

[5mall5nail5]

Have an AC66u and have both SSIDs set the same w/ same password for ease of connection if devices decide to hop over. Is there anything particularly wrong about this?

 

[TonyH]

Hi,
Usually not same between two bands. It'll cause confusion sooner or later or you'll have two connections going. At least SSID should be different between two.

 

[stevech]

A popular solution is to give each WiFi access device a different SSID and choose one that infers its location, such as "JonesDEN", "JonesFAM" so the user can manually chose the nearest, when sitting down in a different area with a handheld. Best you can do with most consumer WiFi.

(or use your initials rather than "Jones" as above).

 

[remixedcat]

Not recommended to have the same SSID some clients have issues with connecting to the one you want and sometimes default to 2.4 Ghz becuase the signal is stronger. Soemtimes windows doesn't list the 5Ghz network, etc..

 

[overdrive31]

In that situation, the dual band client will connect to 5GHz automatically and then roam to 2.4GHz, and will only go back to 5GHz when rebooted. It doesn't cause any problems, unless you are streaming something when you walk out of range of the 5GHz signal, and it must re-establish the connection on the 2.4GHz which causes an interruption in the stream usually.

 

[5mall5nail5]

Thanks guys - very helpful. What about two 2.4GHz APs? Ok to have same SSID/PW?

 

[stevech]

Suggestion is that every access device: AP, WiFi router, have a unique SSID that suggests its location in the home. Like "abcDEN" where abc are your initials.

OK for all to have the same encryption mode and encryption key/password.

 

[tipstir]

I use several SSID for both ESR300H *AP and ESR600H *AP use the same ones (note these two are just Access Points).

All desktops with WiFi, laptops, netbook (have their own SSID-Sys)
All android and windows smartphone and tablets (have their own SSID-Mob)
All wii, network media players and blue ray internet players (have own SSID-Net)

No issues.

 

[sfx2000]

From a design perspective - a WLAN is a WLAN, regardless of bandclass...

So a Single SSID that represent all AP's contained within that LAN is appropriate - however, some older clients get a bit confused, so the option to have unique SSID's is available.

 

[azazel1024]

In that situation, the dual band client will connect to 5GHz automatically and then roam to 2.4GHz, and will only go back to 5GHz when rebooted. It doesn't cause any problems, unless you are streaming something when you walk out of range of the 5GHz signal, and it must re-establish the connection on the 2.4GHz which causes an interruption in the stream usually.

Yup, though it won't necessarily interupt the streaming. Just kind of depends on the client.

I've run dual 2.4/5GHz networks with multiple APs no problem with all APs and all bands using the same SSID. No real issues. I have sometimes seen clients choose 2.4GHz over 5GHz when 5GHz would probably have been faster, but rarely.

The only real issue I've seen is at least the iPhone 5 (maybe other Apple dual band products) take a long time to switch back to 5GHz from 2.4GHz once 5GHz becomes the faster connection. It can take a couple of minutes sometimes.

Otherwise, all windows based clients I've tried do proper speed based band and AP selection pretty smoothly and seamlessly and will generally switch over to the fastest band/AP within about 10-12s. Sometimes a little faster.

I haven't had actual issues were the connection was dropped or severe speed problems with phones or tablets before.

If you do different SSID, you are likely to run in to issues where 5GHz clients might have significantly worse performance than if they could auto switch between 2.4 and 5GHz. I HAVE seen that happen.

 

[overdrive31]

Since when can a device decide on speed? It can only choose based on signal strength and they do not flip flop back and forth. If freshly booted near the AP, they will take 5GHz over 2.4GHz, then as the signal drops on the 5GHz, they roam to 2.4GHz and not back until a reboot.

 

[azazel1024]

Since when can a device decide on speed? It can only choose based on signal strength and they do not flip flop back and forth. If freshly booted near the AP, they will take 5GHz over 2.4GHz, then as the signal drops on the 5GHz, they roam to 2.4GHz and not back until a reboot.

Its not that hard, it can look at both signal strength, MIMO capabilities and bandwidth.

It doesn't take a genius set of firmware to look at surrounding APs and determine possible connection speed and decide whether to switch or not.

Not all drivers have the option in them, but I have seen plenty that offer not just "connect to strongest AP", but also decided based on "fastest speed" instead. I works great in my house, as I have my router setup at 150Mbps 2:2 20MHz 2.4GHz and I have my AP setup as 300Mbps 2:2 40MHz 2.4GHz. It tends to make the appropriate decision on when to switch based on what connection speeds are possible.

If you watch the net status you can see if drop below 150Mbps connection speed as you move away from the AP and generally not lot long after it has dropped below this level, the Router signal is strong enough that it connects over at full 150Mbps.

Changing the settings to connect to the strongest AP and it'll generally switch to the router before it is the fastest device, while I still have a connection >150Mbps on the AP

I've watched, at least Intel, NICs go from 5GHz to 2.4GHz and back to 5GHz as the signal strength get high enough. I've watched my iPhone 5 do the exact same thing as well, it just takes a lot longer before it'll "promote" back up to 5GHz (a couple of minutes).

 

[stevech]

It doesn't take a genius set of firmware to look at surrounding APs and determine possible connection speed and decide whether to switch or not.

It's hard/impossible for the average user, if all the APs have the same SSID.

Not all drivers have the option in them, but I have seen plenty that offer not just "connect to strongest AP", but also decided based on "fastest speed" instead.

Fairly rare capability, eh?

 

[azazel1024]

Uh...its done in the device drivers determining which band and what AP to connect to. Sometimes there are settings you can play with that will "guide" the NIC on which way to go based on user preference, but they all have logic to determine which AP and what band to connect on.

I have only seen a couple of devices that are dual band that would refuse to connect back up to 5GHz once they were on 2.4GHz and then roamed close enough to their AP for the 5GHz to be the better choice. Almost all devices I have seen either make the appropriate choices at the appropriate times, or else they might be a bit "sticky", in that they'll hang on to 2.4GHz for too long before finally bumping to 5GHz a minute or two later.

The change over does sometimes break things like file transfers, video streaming or VOIP, but more often than not I've seen it continue just fine, or at worse, with a brief pause (for instance, file transfers I've seen sometimes stop for a second or two between reconnections before resuming the transfer, usually video streaming doesn't as there is a sufficient buffer that a second or two interuption doesn't do anything. VOIP I do frequently see pauses as it changes bands or reconnects to a new AP and I have seen a dropped connection a couple of times).

 

[stevech]

yes, if there's a TCP connection active, or some UDP/RTSP (streaming) session active, a disruption of packet flow for > x seconds will often cause the application to declare link-lost. That's why enterprise WiFi assures fast handoffs, often 100mSec or less for VoIP such as Vocera's.

 

[overdrive31]

Specific Driver settings..so not by default? I have never once seen my dual band clients, flip-flop back and forth, that's including 3x iPhone 5S'

 

[Terry Kennedy]

It's hard/impossible for the average user, if all the APs have the same SSID.

Just as another data point, I have 4 AP's (Cisco Aironet 1252's w/ 2.4 and 5 GHz modules). All of them have the same SSIDs - "XYZ" for 2.4 GHz and "XYZ5" for 5GHz. One of them has a secondary 2.4GHz SSID, "CLIMATE", for some HVAC equipment located nearby (this SSID isn't on the other AP's, since if the air conditioners start moving around, I've got bigger problems). CLIMATE is on a different VLAN for security reasons.

These are the autonomous version, with no WLAN controller.

There's also another AP, a D-Link something or other, SSID "REMOTE" which operates on a completely isolated LAN for my various Pronto Pro remote controls and extenders. Prontos are extremely picky about what sorts of APs they will talk to, and aren't very good at WPA so I'm using WEP for this one. Traffic is very low on this LAN, and all somone could accomplish is a replay attack to change the channels on my TV, etc.)

 

[azazel1024]

I suppose it depends on the NIC drivers. My Intel cards have it set to default to the best speed band, probably the way it should be. I've watch it flip bands in inSSIDer once or twice. I don't have a 5GHz network at home to do extensive testing with (this was at my brother's apartment).

My iPhone 5 also does as well. It takes a couple of minutes though, not the few seconds I've seen with Intel NICs.

I can't speak to other NICs, like Broadcom or Atheros.

 

[sfx2000]

It's hard/impossible for the average user, if all the APs have the same SSID.
Fairly rare capability, eh?

Actually fairly common these days... there are edge cases, but most modern dual-band clients look at RSSI, along with other characteristics.

 

[stevech]

Actually fairly common these days... there are edge cases, but most modern dual-band clients look at RSSI, along with other characteristics.

I was referring more to when you have 2+ access devices, same band.