Is your Router/Mobile Device mature enough to switch between 2.4 & 5 GHz ?

[IAAI]

Today's routers usually come with a feature of using 1 SSID for both 2.4 & 5 GHz. I never understood how does this actually work.
***Before answering these questions just Imagine you are living far far away from any interference :
1- What is your option on the whole thing? * BTW I know we have 2x 5GHz now a days in the same router
2- Does this require the the router to use more resources ? (CPU/Memory/Load)
3- If each band comes with a unique Mac address, which mac address is going to appear to the client ?
4- Is the client going to notice any lag or connection drop if his device decided to switch ?
5- Is the client going to use the same old IP after the switch?
6- What are the factors affecting the handheld devices to decide to switch or not?
7- Does switching that often can affect the handheld devices in battery/power consumption?

Hit me

 

[sfx2000]

1) My thoughts are common SSID

2) No additional CPU/Mem impact on a dual radio AP

3) Each radio will have it's own MAC address, and each radio will host it's own basic service set - the client will see the MAC address of the AP hosting the BSS

4) Moving from one AP/Band to the other is client dependent - some do it better than others, if you run a common SSID, the transition from one to the other should be easier since it won't have to do the WPA2 key exchange and DHCP lease over again when it moves from one to the other

5) Common SSID - typically yes, as IP is above the MAC layer, and the DHCP server binds the client IP address to the client MAC address - moving from one AP to the other doesn't change the client MAC address

6) Again, depends on client implementation - Apple dual band devices tend to be biased towards 5GHz if present - Same with Intel dual band cards on Win7/8 - I've seen some braindead Realtek drivers on Win7/8 that don't handle dual band very well without some advanced configuration setting changes

7) Power consumption - again, depends on client implementation and link conditions, along with network activity

hth...

sfx

 

[htismaqe]

I AM living far away from any interference - my nearest neighbor is over a mile away and the only time I see another AP on the wifi analyzer is when the county maintains the road.

I use a common SSID for both 2.4Ghz and 5.0Ghz and it works great. To answer some of your specific questions:

• Resource load on my WRT1900AC is the same regardless of whether I use same or separate SSIDs.
• Your devices don't generally "see" a MAC address. They "see" an SSID. Which one they see is generally dependent on the client but as SFX2000 mentioned, my Apple and Intel devices tend to prefer 5Ghz unless the signal drops to about 2 bars.
• For the most part, I don't see any lag when they switch. Most of the time, I don't even notice them switch. In fact, having my iPhone 6, for example, switch is FAR less noticeable than stepping just outside of optimal 5Ghz range and having it sit there and retransmit trying to load a webpage.
• Clients retain their IP address.
• I haven't noticed any difference in battery consumption on my mobiles devices.

 

[azazel1024]

Agreed with Htismage and sfx2000.

To expand on 6, the client will only look to switch bands or switch access points based on a set of criteria that the drivers tell the OS. Generally it will not even LOOK at other SSIDs/base stations unless that criteria is met OR the OS specifically asks to. An example of the OS asking to, is you are looking manually for nearby networks (ex. in windows clicking on the network icon to see the nearby wifi networks. Or running a Wifi analyzer).

The drivers will have their own settings for when to begin looking around. Some drivers allow you to tweak when this happens, some do not. GENERALLY the default configuration of most drivers, across OS, is that they'll begin looking for other networks once the RSSI drops to below -70dBm. Then, they will generally shift to a new access point/band on the same network if there is a member of the SSID that is at LEAST 15dB higher in signal strength.

In generally devices will not roam to another network unless they are specifically configured to do this. In windows some wifi drivers will allow you to select the flag "roam to other networks". In my experience it is iffy if even then they'll choose to go to a different SSID. Which is why you generally want a unified SSID across your physical network. Else wise, devices have to manually roam, they won't do it on their own.

Anyway, as above, in default configuration, a device on 5GHz once it's signal strength dropped to, say, -71dBm would start periodically scanning both bands picking up beacon frames. If one of them had an RSSI of -55dBm, 16dB stronger than the current connection, the client would then disassociate with the current base station and then associate with the new one (or new band on the existing base station. Though it might be possible if it is the SAME base station, but a different band, the disassociate/reassociate process may not need to occur. Not sure)

This scanning process CAN use more power. I don't really notice any impact on battery life and I have the roaming settings on all of my devices where it is configurable cranked to the max. Most drivers (most of this relates to windows, as you can't configure it under iOS or Android generally, not sure about OSX, but the default configuration in Windows GENERALLY seems to be the behavior of other operating systems) at max settings will begin looking at -60dBm and will switch if there is a band/AP that is at least 10dB stronger. The "weakest" settings are -80dBm and 20dB stronger. You can also mix, where it won't look until -80dBm, but it'll transition if there is one 10dB stronger, or -60dBm it'll look, but won't transition until it sees one 20dB stronger and in-betweens.

 

[stevech]

that is, the strategy used by brand X WiFi client device - is whatever X decided to do. Or didn't decide.

With rare exception in consumer gear, the router or AP has no ability to "direct" the client to change bands or AP choice. This is because base station directed or base station recommended handoffs are not part of the IEEE standards as adopted for 99.9% of consumer gear.

 

[sfx2000]

that is, the strategy used by brand X WiFi client device - is whatever X decided to do. Or didn't decide.

With rare exception in consumer gear, the router or AP has no ability to "direct" the client to change bands or AP choice. This is because base station directed or base station recommended handoffs are not part of the IEEE standards as adopted for 99.9% of consumer gear.

Common SSID in the SOHO space is about as good as one can get - within the budget of less than $250USD...

I consider this "lazy" roaming - as it's all based on client decisions and their implementation - most actually do it pretty well. There's a few brain dead client driver implementations, but generally, having the client make the decision works in many cases...

To get to the realm of controlled/managed Network Directed Handoffs and Roaming - well, then we need to ratchet up the costs by at least 10 fold - a Wireless LAN Controller, and a couple of Enterprise Grade AP's - and yes, there, one can take into consideration many more capabilities - target WiFi Alliance Enterprise Voice Capabilities, as the neighbor reporting, bandwidth management, and other parameters, need to be taken into consideration..

 

[azazel1024]

I am still mildly surprised none of the SOHO focused manufacturers has moved towards a controller/directed hand-off model. I realize that this is extra firmware validation, but I'd think it would be broadly compatible with existing hardware. IE it is a validation and development issue, not a BOM issue.

Be a great way for SOHO manufacturers to sell more stuff. "buy our router and you can either pickup a 2nd, or 3rd or TONS of routers from us, or buy add on access points, or range extenders, in fact ANY of our wireless gear, and it'll integrate for a seamless wireless experience across your house! No more dead spots and wireless clients hanging on to a weak signal! Wifi Whole Home(tm) by Netgear"

Or whatever marketing-ees.

 

[IAAI]

Be a great way for SOHO manufacturers to sell more stuff. "buy our router and you can either pickup a 2nd, or 3rd or TONS of routers from us, or buy add on access points, or range extenders, in fact ANY of our wireless gear, and it'll integrate for a seamless wireless experience across your house! No more dead spots and wireless clients hanging on to a weak signal! Wifi Whole Home(tm) by Netgear"

Or whatever marketing-ees.

This could destroy their future plane/profit/customers - They are playing a game of numbers and antennas they don't have time for sweet/dead spots at the moment. Once they run out of regular consumers marketing ideas then they might listen

Now a days everyone is looking to buy something bigger/better/cheap and it works out of the box without any effort to set up or even understand how it works.
I have a feeling in the near future they are gonna come out with a way of you buying something and it will unbox it's self and work on it's own without you even touching it
This could be the highway towards ignorance

 

[sfx2000]

This could destroy their future plane/profit/customers - They are playing a game of numbers and antennas they don't have time for sweet/dead spots at the moment. Once they run out of regular consumers marketing ideas then they might listen

Now a days everyone is looking to buy something bigger/better/cheep and it works out of the box without any effort to set up or even understand how it works.
I have a feeling in the near future they are gonna come out with a way of you buying something and it will unbox it's self and work on it's own without you even touching it
This could be the highway towards ignorance

You make some really good points - it's not a technology issue, that's solved... it exists, and we could see products tomorrow - core Smart Router, and dumb AP's managed from the router GUI or a desktop Web interface or App on the tablet/smartphone...

It's a business concern - how to extract value from a product at a price point that people are willing to pay... and with the SOHO business, it's about keeping customers buying the products that roll off the end of the factory line, as most SOHO users are not into subscription packages just yet... so unit sales are absolutely key here..

Cloud services (Storage and Content) are making roads into that particular forest, but not yet for SOHO networking gear - to whit - Cisco/Linksys's failed experiment with the early iterations of "Cloud Connect" with terms/conditions that many took exception to on the Valet line of AP/Routers...

 

[sfx2000]

Funny how this forum thread popped up...

http://www.smallnetbuilder.com/basi...751-snb-answer-guy-how-many-ssids-is-too-many

sfx

 

[IAAI]

Funny how this forum thread popped up...

http://www.smallnetbuilder.com/basi...751-snb-answer-guy-how-many-ssids-is-too-many

sfx

Sixth Sense

 

[sfx2000]

speaking from experience, simple is much better... more effort perhaps...

 

[azazel1024]

Depends if the effort is on the front-end or the back-end. I typically prefer to front-end my workload/effort so that future stuff is much easier.

 

[stevech]

Paraphrasing post #13:

For an informed shopper: "You Get What You Pay For"

 

[Chrysalis]

all my phones in this scenario (android) will connect to the 2.4. Which is why I now always give my 5ghz a unique ssid.

 

[stevech]

I too have different SSIDs for 2.4 and 5GHz. Last character of SSID is 2 or 5.

 

[htismaqe]

all my phones in this scenario (android) will connect to the 2.4. Which is why I now always give my 5ghz a unique ssid.

Really? I have a Samsung Galaxy Note and a Samsung Galaxy Tab. Both connect to the 5Ghz automatically when in range.

 

[Chrysalis]

yes

I can think of 2 possible reasons.

1 - my 2.4ghz has a more pwoerful signal so the phone see's it as the better choice.
2 - when I first turn on wifi my 5ghz ssid seems to take an extra second to appear in the AP list.

It is worth pointing out here even with a weaker signal my 5ghz performance blows my 2.4ghz performance out of the water.

 

[IAAI]

What is your router ?

Try this :
Make your phone Forgets your SSID then Go to advance in wifi setting and make sure there is no preferable band then Turn off your phone

Restart your router and give it 3 mins to boot-up

Turn on your phone while setting next to your router the connect to your SSID and report back [emoji1]

* make sure your 5 GHz is not in a weird channel

 

[sfx2000]

yes

I can think of 2 possible reasons.

1 - my 2.4ghz has a more pwoerful signal so the phone see's it as the better choice.
2 - when I first turn on wifi my 5ghz ssid seems to take an extra second to appear in the AP list.

It is worth pointing out here even with a weaker signal my 5ghz performance blows my 2.4ghz performance out of the water.

Depends on the client firmware on the Android - it may prefer 2.4GHz to get a fast connection to get/send data, and then when time/apps permit, hand up to 5GHz... and 5GHz in the DFS/TPC channels may require a bit of quiet time, even when the AP is found, that why lot's of folks shy away from those channels...

So using a common SSID might be a good thing.