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VX9000 total wireless LANs ?


Hi guys,

Bonjour,

Please help me that, in VX9000 total of how many WLANs can able to add .?

14 replies

Userlevel 4
From a management perspective, no more than 6 WLANs. This will keep the beacons down to a low roar for better performance.
Shay Weir wrote:

From a management perspective, no more than 6 WLANs. This will keep the beacons down to a low roar for better performance.

Hi Shay,

I'm using the same for different locations all-round India more than 150+ now. Would wants to know that for VX9000 what is maximum capacity we may add.

Likewise RFS4000 has only limited of 256WLANs.

Please help me,

Userlevel 4
Shay Weir wrote:

From a management perspective, no more than 6 WLANs. This will keep the beacons down to a low roar for better performance.

Yes. You can have many WLANs configured. The limitation of 6 is on the AP side itself. There is the confusion. Controller wise the numbers are as has been stated for the WLANs. Just do not put more than 6 on each AP. If you can standardize across your environment, that will hep with making changes in the future. Change one, they all change. You can also use wlan-overrides to customize each location.

Hope this helps to clarify the limit of 6 WLANs - per/AP not controller.
Shay Weir wrote:

From a management perspective, no more than 6 WLANs. This will keep the beacons down to a low roar for better performance.

Thanks for your clear clarification Shay Weir.

If I'm using 9 SSID which all are in hidden mode on same access Point over a corporate setup total of 53 Access points I'm using it.

It will cause any impact. If yes means please help me to sort it out.

FYI.
Access Point model :- AP7532
Controller :-- VX9000
Userlevel 5
Hello Vimalraj,

If you're asking about the scalability of the VX9000 then the total number of WLANs/device would be 1022 taking into consideration the min hardware resources that should be allocated:

3 x VCPUs @ 2.4GHz
5GB RAM
5GB HDD
Userlevel 6
Hello Vimalraj,

As per data sheet the limitation is 1,022 WLAN entries.
This is code limitation as VX does not broadcast WLAN at all.

Theoretical maximum of WLANs per AP is 32 (in configuration), with maximum of 8 SSID per radio (broadcasted).
However, you shall not exceed 6 WLANs per radio as written by Shay above.
Even 6 is very high number which will cause significant degradation of radio performance.
See this SSID Overhead Calculator by Revolution WiFi

Rule of thumb - do not use more than you need and try to aggregate wherever you can.

Regards,
Ondrej
Ondrej Lepa wrote:

Hello Vimalraj,

As per data sheet the limitation is 1,022 WLAN entries.
This is code limitation as VX does not broadcast WLAN at all.

Theoretical maximum of WLANs per AP is 32 (in configuration), with maximum of 8 SSID per radio (broadcasted).
However, you shall not exceed 6 WLANs per radio as written by Shay above.
Even 6 is very high number which will cause significant degradation of radio performance.
See this SSID Overhead Calculator by Revolution WiFi

Rule of thumb - do not use more than you need and try to aggregate wherever you can.

Regards,
Ondrej

Thanks a lot Ondrej,
Ondrej Lepa wrote:

Hello Vimalraj,

As per data sheet the limitation is 1,022 WLAN entries.
This is code limitation as VX does not broadcast WLAN at all.

Theoretical maximum of WLANs per AP is 32 (in configuration), with maximum of 8 SSID per radio (broadcasted).
However, you shall not exceed 6 WLANs per radio as written by Shay above.
Even 6 is very high number which will cause significant degradation of radio performance.
See this SSID Overhead Calculator by Revolution WiFi

Rule of thumb - do not use more than you need and try to aggregate wherever you can.

Regards,
Ondrej

Thanks for your clear clarification Ondrej,

If I'm using 9 SSID which all are in hidden mode on same access Point over a corporate setup total of 53 Access points I'm using it.

It will cause any impact. If yes means please help me to sort it out.

FYI.
Access Point model :- AP7532
Controller :-- VX9000
Userlevel 6
Ondrej Lepa wrote:

Hello Vimalraj,

As per data sheet the limitation is 1,022 WLAN entries.
This is code limitation as VX does not broadcast WLAN at all.

Theoretical maximum of WLANs per AP is 32 (in configuration), with maximum of 8 SSID per radio (broadcasted).
However, you shall not exceed 6 WLANs per radio as written by Shay above.
Even 6 is very high number which will cause significant degradation of radio performance.
See this SSID Overhead Calculator by Revolution WiFi

Rule of thumb - do not use more than you need and try to aggregate wherever you can.

Regards,
Ondrej

Hi Vimalraj,

what do you mean by "hidden"?
Is it no broadcast-ssid or no answer-broadcast-probes?

  • no broadcast-ssid just leaves the SSID field empty, but beacon still has to occur due TIM etc.
  • no answer-broadcast-probes is mitigating active scanning with null SSID / blank request but will still respond to direct probe request.
These options won't help to relieve the utilization.
Based on the capacity planning and number of clients you may, or may not, experience issues with the radio performance.

In other words:

If you do not experience any issues so far, you probably did not exceed the capacity.
If you do experience client stability issues this is the point whee I would start considering wireless site survey / check the capacity planning.

Regards,
Ondrej
Userlevel 3
Hi Vimalraj,

My colleagues have mentioned that having lots of SSIDs active is not good. This is because each SSID causes overhead in the Wi-Fi network and ultimately reduces the amount of capacity available for client traffic

For further details and a calculator to understand just how much overhead is caused by this issue, please see here: http://www.revolutionwifi.net/revolutionwifi/p/ssid-overhead-calculator.html

Best regards,
Darrel.
Userlevel 4
When running that many SSIDs on a single AP (x53) the management traffic alone will kill performance. Several things to consider. Lowest data rates. Set them to only connect at nothing lower than 9MB, best would be 18 or 24MB data rate. This will force all to connect at higher rates, this leaving ample room for traffic. AP management traffic will also use the higher rates to pass traffice to the RF-Domain. This is good for the 2.4GHz radio. For those on 5GHz, you should be okay to leave at default.

When you do not broadcast the SSID, each AP has to ask every AP what they have to offer. Again, this creates more non data overhead. Best to go ahead and broadcast the SSID. Hacker can find even if not broadcast if that is what you are worried about. Just be sure to enable strong security measures on each.

To help reduce the number of SSIDs, try using dynamic vlan assignments. This works with your AAA policy and RADIUS server. This helped us out greatly to eliminate 4 SSIDs so far. When issuing a "show wireless clients", add the column to also include the vlan. Guest or freewifi, should still have its own SSID and routed directly out. Other Corporate SSIDs, should roll into 1. Legacy devices may need their own based on what type of authentication functions they can handle.

You will need to research each device type and their wireless capabilities to determine basic lowest rates (work to raise up to 24MB).

Research each device authentication capabilities to eliminate SSIDs and use dynamic vlan assignments using AAA policy and RADIUS.

Hope this helps.
Userlevel 6
Shay Weir wrote:

When running that many SSIDs on a single AP (x53) the management traffic alone will kill performance. Several things to consider. Lowest data rates. Set them to only connect at nothing lower than 9MB, best would be 18 or 24MB data rate. This will force all to connect at higher rates, this leaving ample room for traffic. AP management traffic will also use the higher rates to pass traffice to the RF-Domain. This is good for the 2.4GHz radio. For those on 5GHz, you should be okay to leave at default.

When you do not broadcast the SSID, each AP has to ask every AP what they have to offer. Again, this creates more non data overhead. Best to go ahead and broadcast the SSID. Hacker can find even if not broadcast if that is what you are worried about. Just be sure to enable strong security measures on each.

To help reduce the number of SSIDs, try using dynamic vlan assignments. This works with your AAA policy and RADIUS server. This helped us out greatly to eliminate 4 SSIDs so far. When issuing a "show wireless clients", add the column to also include the vlan. Guest or freewifi, should still have its own SSID and routed directly out. Other Corporate SSIDs, should roll into 1. Legacy devices may need their own based on what type of authentication functions they can handle.

You will need to research each device type and their wireless capabilities to determine basic lowest rates (work to raise up to 24MB).

Research each device authentication capabilities to eliminate SSIDs and use dynamic vlan assignments using AAA policy and RADIUS.

Hope this helps.

Shay,

I have to admit that using dynamic VLAN assignent + AAA sound like really elegant way to do the sorting!

Good job

Regards,
Ondrej
Userlevel 7
Here a matrix on how the number of SSID and MBR affects the util in the air.
So try to lower the number of SSIDs per radio and increase the MBR to decrease the util.

Userlevel 4
Too many APs and too many SSIDs will cause performance issues if not tuned correctly. It does not matter who the vendor is Extreme, WiNG, Cisco, Aruba, Aerohive... If your wireless network is not configured correctly, there will be problems. The best real advise is to work with your local Extreme WiNG SE to assist in tuning your environment to provide the best experience for your customers.

This is what they do for you.
Userlevel 4
Shay Weir wrote:

Too many APs and too many SSIDs will cause performance issues if not tuned correctly. It does not matter who the vendor is Extreme, WiNG, Cisco, Aruba, Aerohive... If your wireless network is not configured correctly, there will be problems. The best real advise is to work with your local Extreme WiNG SE to assist in tuning your environment to provide the best experience for your customers.

This is what they do for you.

Here is the link to the actual SSID Overhead Calculator:
http://bit.ly/wifissidoverhead

Give it a spin....

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