Multiple AP's on the one SSID - Best Practice?

[Salty Dog]

Hello all, after doing some reading on here, i can't quite find the answer to my question.

The biggest issue i find these days is building a larger Wireless Network (Campus Style) for larger properties or multi level properties.

Generally i have already wired a Cat6 network in place, so it seems logical to me to just add AP's to the wired network in such a way as to provide an entire wireless coverage. Using the wired network as a backbone.

My common topography would be as below:

Modem/Router with DHCP ON (10.0.0.138) ---------> 24 Port Giga Switch -------> Access Point 1 (10.0.0.200) ....... Access Point 2 (10.0.0.210) ........ Access Point 3 (10.0.0.220) ........ Access Point 4 (10.0.0.230) on the Wired Ethernet, all wired in Star Topography back to the Switch on an individual Cat 6 cable.

Then in the Wireless Setting of each Access Point:
SSID = the same (eg: FREE WIFI)
Security Settings = the same
Channel = Different (trying to use 1,6 and 11)

With this set up, i am hoping for the Clients to experience a Seamless Roaming under the one SSID and just connecting to the AP with the strongest signal.

In real life, i know this is not always the case, as some clients remain stuck to the first AP even when they have physically moved into an area where the next AP is only meters away??? From what i read, this is a client based problem.

Yet i have a friend whom set up a wireless network with 3 TP-Link WA830RE Range Extenders (In AP mode, using a wired back bone) and he was able to set up HD streaming from a NAS, then walk around the property with his laptop, hoping from AP to AP without even a glitch in the HD streaming as it moved to different AP's seamlessly.

Can someone please set me straight on the Best Practice to setting up WiFi Roaming?

My ultimate goal would be to have Dual Band AP's (2.4 and 5ghz) so things like MacBooks and Ipads could use the 5Ghz network, leaving the 2.4Ghz network for other clients in the same Roaming way.

From what i have read and been told... the standard method is to use:

1. The same SSID
2. The same Security
3. Different Channels (something i haven't tried)
4. The same brand/type of AP if at all possible throughout the wireless network
5. Leave all Address Handling (DHCP) back at the Modem/Router.

I really dont want to make different SSID's if possible, as the end users are just family people and kids....

Any ideas... Am i at least trying to do it right?

Many Thanks

 

[Salty Dog]

Note sure if External links are allowed, but i used to follow the advise of this guy, as i used to buy his products.
Written back in 2006... but i think the principle still stands.
In the examples he gives, its more about a FULL WIRELESS Campus, that doesn't use a Wired Backbone.
But i suspect for the sake of this argument, i can just remove his "Bridged" AP's and consider that a Wired connection for the Roaming to still work.

http://nuke.freenet-antennas.com/documents/RoamingWithUltraWAPs.pdf

 

[sfx2000]

All the same SSID for the AP's - one DHCP server, common passphrases's if you're using WPA/WPA2 Pre-Shared Keys. Make sure that the AP's are set up as AP's and not routers (good article on this site on how to convert a SOHO router into an AP, basically disable DHCP, give it a fixed IP on the same subnet outside of the DHCP range, and plug the ethernet into one of the LAN ports, rather than the WAN port.

Channel management - for capacity, do a +5 channel re-use (1/6/11) - if not a lot of demand and you want better roaming, you can try all on same channel - if you do this, use inssider or similar and try to get 20 dB separation at the different AP's, most clients will swing over (some won't).

should work fine...

 

[stevech]

Hello all, after doing some reading on here, i can't quite find the answer to my question.

The biggest issue i find these days is building a larger Wireless Network (Campus Style) for larger properties or multi level properties.

Generally i have already wired a Cat6 network in place, so it seems logical to me to just add AP's to the wired network in such a way as to provide an entire wireless coverage. Using the wired network as a backbone.

My common topography would be as below:

Modem/Router with DHCP ON (10.0.0.138) ---------> 24 Port Giga Switch -------> Access Point 1 (10.0.0.200) ....... Access Point 2 (10.0.0.210) ........ Access Point 3 (10.0.0.220) ........ Access Point 4 (10.0.0.230) on the Wired Ethernet, all wired in Star Topography back to the Switch on an individual Cat 6 cable.

Then in the Wireless Setting of each Access Point:
SSID = the same (eg: FREE WIFI)
Security Settings = the same
Channel = Different (trying to use 1,6 and 11)

With this set up, i am hoping for the Clients to experience a Seamless Roaming under the one SSID and just connecting to the AP with the strongest signal.

In real life, i know this is not always the case, as some clients remain stuck to the first AP even when they have physically moved into an area where the next AP is only meters away??? From what i read, this is a client based problem.

Yet i have a friend whom set up a wireless network with 3 TP-Link WA830RE Range Extenders (In AP mode, using a wired back bone) and he was able to set up HD streaming from a NAS, then walk around the property with his laptop, hoping from AP to AP without even a glitch in the HD streaming as it moved to different AP's seamlessly.

Can someone please set me straight on the Best Practice to setting up WiFi Roaming?

My ultimate goal would be to have Dual Band AP's (2.4 and 5ghz) so things like MacBooks and Ipads could use the 5Ghz network, leaving the 2.4Ghz network for other clients in the same Roaming way.

From what i have read and been told... the standard method is to use:

1. The same SSID
2. The same Security
3. Different Channels (something i haven't tried)
4. The same brand/type of AP if at all possible throughout the wireless network
5. Leave all Address Handling (DHCP) back at the Modem/Router.

I really dont want to make different SSID's if possible, as the end users are just family people and kids....

Any ideas... Am i at least trying to do it right?

Many Thanks

Unless you use an Enterprise Grade WiFi system such as from Cisco/Aironet or Aruba, with managed APs, your scheme will have the consumer-grade problems. IEEE 802.11 does not require a client device to choose the best-signal (strongest for which the client has decryption keys). Usually, a client device (laptop, tablet, smartphone), will choose first-heard during a channel-scan. A scant few take the time to sit for 100mSec (the default beacon interval) on each channel. Few do, as it takes too much time and battery usage.

So non-Enterprise WiFi burdens the human user of the Client to choose best-AP if their device does not. This manual process is either "well, I'm in this area and I know that the AP whose SSID is xyx is the best". Or a user looks at a list and notices which has the best signal (kinda geeky for the typical user).

This scenario requires each AP to have a different SSID, like "Floor2 West" or some such.

As to using different channels... Minor impact if you do or don't. Depends on how heavily used (constant data traffic flows) each AP has. If you do elect to use different channels, in 2.4GHz, use 1, 6 and 11. If you have lots of APs, do a "frequency reuse" pattern where channel n is reused at the the most distant place from other APs on that channel.

 

[Salty Dog]

Thank you so much for the prompt replies guys.

I am caught between what i know (self taught or on-site/at home experimentation) and what SoHo Manufactures like TP-Link etc tell me... and i mean by way of an answer from their so called "Network Engineers" when i email them a question.

Yes believe it or not, they actually quote the clients will connect to the AP with strongest signal when mobile (same SSID), even though i know that not to be true in application, especially when the initial AP still has some range in the same area of the now closer, stronger AP (which is the whole point of roaming isnt it)

Ok, i shall set up the customers network as first discussed, with one SSID... if that idea fails to work effectively, i shall go back to the old never fail, different SSID per location.
And as mentioned, generally a location specific SSID like "Lounge", "Kids Room", "Master Bedroom".

I will check and see if i can control the power levels on these devices... As they are located close.
2 on one level around 15meters apart, the third is downstairs with a concrete floor/ceiling between them, so there is good separation there, although one of the upstairs APs in directly above it, probably not more than 4 meters away, but as mentioned, a concrete reinforced floor/ceiling between them...
I can see it may pay to remove the Centrally located AP upstairs and move it to the opposing end of the house, pushing the 2 upstairs units 35 meters apart with several plaster walls in between.

For most Domestic level instals, the customer would not have the budget (or care factor) to purchase commercial or enterprise gear with fast hand-offs.

So i will try the above suggestions and report back.

Thank You

sfx2000, you are indeed correct, the installation i speak of had 2 x Dual Band Routers purchased by the owner, they are set up at Access Points, with DHCP disabled, a fixed IP on Ethernet plugged into the LAN port.
I will go and double check if the Fixed IP of the 2 units is above the DHCP addressing range.
As someone else set them up.... i am not totally sure about this.

 

[sfx2000]

One other thing you might want to check out coverage with, esp. on a large site with multiple AP's...

Ehaku Heatmapper

http://www.ekahau.com/products/heatmapper/features-a-screen-shots.html

sfx