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New Member

WLC with 2 WLANs, 1 voice @ 2.4GHz and 1 data @ 5GHz 802.11n

I have a WLC 4400 series and am using 1142n APs.  Am planning on adding Wireless IP Phones such as 7921/7925 as well as a couple 9971's.  Is it possible to have 2 WLANs, one to connect the voice endpoints to running @ 2.4GHz and another WLAN with a different SSID for data clients @ 5GHz?  All data clients have 802.11n NICs and can operate @ 5GHz.  I have enough APs so that the lessened range of 5GHz won't pose any issues.  Ideally I'd like to see connection rates in the 240mbps-300mbps range on the data clients with data throughput rates of 100mbps+ (I don't think this ought to be an issue, I'm aware that wireless is half-duplex and that connection rates do not necessarily indicate actual throughput rates).  I am also NOT a wireless expert.  I'm still fairly new to working with the WLC and the managed APs as such.  

The reason for 2.4GHz and 5GHz simultaneously is that the voice endpoints are all 2.4GHz radios, I believe 802.11b/g.  I also want to keep voice clients separate.  This way, I believe I can optimize one WLAN for data clients without having them "suffer" so to speak by having to operate at a lower level as the voice clients.  Also, I want the voice separate for quality there (separate voice VLAN).  If I am correct, 802.11n data rates can also be achieved @ 2.4GHz, but only using the 20MHz as opposed to 40MHz width.  So I'd like one WLAN to be 2.4GHz, 20MHz (voice) and the other WLAN 5GHz, 40MHz (data).

I'd like to hav both WLANs broadcasted from all the APs simultaneously.  Am I correct that such a configuration is possible with the WLC 4400 series and Aironet 1142n APs?  WLC is running 7.0.240 btw, current stable.  I'm also starting with a clean config on the WLC.  All DHCP will be handled by an external DHCP server also.  Thank you very much for any suggestions/guidance on this.  Your thoughts are greatly appreciated!

I'll be happ to supply any config information to assist with this, just let me know what is desired/useful.

 

Everyone's tags (4)
1 ACCEPTED SOLUTION

Accepted Solutions
Hall of Fame Super Gold

I only have 1 WLC, it is a

I only have 1 WLC, it is a 4402-50.  I believe that 7.0.240 is the most current release for that model.

7.0.250.X is the latest release for the WLC4400.

Release Notes for Cisco Wireless LAN Controllers and Lightweight Access Points for Release 7.0.250.0

If I understand you correctly, I'm best creating 2 WLANs, but both at 5.0GHz for both data and voice?

What I'm saying is enable both radios on the SSID doesn't hurt.  At the end of the day, the wireless NIC of the client will determine what radio to choose from.  You could potentially ensure you have high throughput in your 802.11b/g radios if you disable the low speed data rates such as 1-, 2-, 5.5- and 11 Mbps.  Make 12 Mbps and above as supported and 18 Mbps as Mandatory.

 

Read the Deployment Guide I've posted below.   Particularly with the 7921G/7925G, they require either 12 Mbps as Supported or Mandatory.  Do not disable this data rates or you won't be able to make any calls.  Trust me.  I've made that mistake already.  

6 REPLIES
Hall of Fame Super Gold

Yes this can be done but it's

Yes this can be done but it's not "best practice". The problem with 2.4Ghz is co-channel interferrence. This is even true when you have neighbors who have a lot of 2.4 Ghz deployment. This is why the recommended 7921G/7925G voice deployment recommends setting the phones to have 5.0 Ghz as primary and only go to 2.4 Ghz when the primary signal goes beyond the allowed threshold. With your voice handsets, make sure you load firmware version 1.4(3) and later. Because you have two different models of WLC, I would also recommend you use the same firmware, like 7.0.250.X.
New Member

Thank you for your prompt

Thank you for your prompt response.  I only have 1 WLC, it is a 4402-50.  I believe that 7.0.240 is the most current release for that model.  I think anything higher I need to go to the WLC5508 (or vWLC?)

Also, I wasn't aware that the 7921/25 were 5GHz, since they are both 802.11g.  Thank you for the information. 

If I understand you correctly, I'm best creating 2 WLANs, but both at 5.0GHz for both data and voice?

Also, sorry to confuse the issue further, but I was thinking about this after writing the original post, I'd like to also have a "guest" WLAN that supports both 2.4GHz and 5.0GHz for maximum client compatibility (as I have no way of knowing what tpye of WLAN NIC would be in guest devices).  Am I correct in assuming that I would create a separate WLAN for all these, including a separate SSID.  

The part that is confusing me some now is the "AP Groups".  Do I leave a single "Default-group" and create multiple WLANs with that.  If I'm correct, this way I can push the WLANs and SSIDs out through all the WAPs in that group.  I want these WLANs to be available from any AP in the organization, not have some APs for one WLAN, other APs for another WLAN, etc.

 

Hall of Fame Super Gold

I only have 1 WLC, it is a

I only have 1 WLC, it is a 4402-50.  I believe that 7.0.240 is the most current release for that model.

7.0.250.X is the latest release for the WLC4400.

Release Notes for Cisco Wireless LAN Controllers and Lightweight Access Points for Release 7.0.250.0

If I understand you correctly, I'm best creating 2 WLANs, but both at 5.0GHz for both data and voice?

What I'm saying is enable both radios on the SSID doesn't hurt.  At the end of the day, the wireless NIC of the client will determine what radio to choose from.  You could potentially ensure you have high throughput in your 802.11b/g radios if you disable the low speed data rates such as 1-, 2-, 5.5- and 11 Mbps.  Make 12 Mbps and above as supported and 18 Mbps as Mandatory.

 

Read the Deployment Guide I've posted below.   Particularly with the 7921G/7925G, they require either 12 Mbps as Supported or Mandatory.  Do not disable this data rates or you won't be able to make any calls.  Trust me.  I've made that mistake already.  

Hall of Fame Super Gold

Am I correct in assuming that

Am I correct in assuming that I would create a separate WLAN for all these, including a separate SSID.  

This is correct.  You create an new and separate Guest SSID.  It will depend on how well "protected" you want to be.  If you have a firewall, for instance, you can assign the default gateway of the Guest SSID on the firwall so that all traffic from this SSID goes into one direction.  There is no way for Guest SSID to share corporate resources.  


Also you can also enable time-based ACL so you can disable the dynamic VLAN outside business hours.

Hall of Fame Super Gold

The part that is confusing me

The part that is confusing me some now is the "AP Groups".  Do I leave a single "Default-group" and create multiple WLANs with that.  If I'm correct, this way I can push the WLANs and SSIDs out through all the WAPs in that group.  I want these WLANs to be available from any AP in the organization, not have some APs for one WLAN, other APs for another WLAN, etc.

It depends on how good you can understand the concept of AP Groups.  One of my favorite tricks is I make sure all my SSID do not have an Index number between 1 to 16.  Any SSID falling between the index number of 1 to 16 will immediately fall into "default" AP Group.  So if someone unauthorize plugs a Cisco AP into your switch, they can potentially use all the SSID that are in the default AP Group.  

 

All my SSID starts with Index number 17.  Any unathorized AP plugged into our network will immediately NOT broadcast any SSID.  

Hall of Fame Super Gold

Thank you very much for

Thank you very much for taking the time rate our posts.  laugh

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