Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Community Member

Single SSID versus Multiple SSID

Hi

We are looking at deploying wireless at five large campus sites one in each state.

Does anyone have ideas on deploying single SSID verus multiple SSID for each location.

Are their advantages from reporting and security to identify rouge devices associated to

a unique SSID.

The question was asked that it would be easier to configure single SSID for wireless scanner

devices than having seperate SSID different locations.

Would appreciate any experience on this design

1 ACCEPTED SOLUTION

Accepted Solutions
Hall of Fame Super Gold

Re: Single SSID versus Multiple SSID

Mate,

Remember, when you're dealing with WLC, you do not configure the APs.  You configure the WLC and the configs will be propatated to all the APs the WLC manages.

On the WLC, you can use up to 18 SSIDs but you can configure 1,024.

Currently, I have three SSIDs and one of them is for VoWLAN.

By the way, some hand-held scanners do not like non-broadcasting (hidden) SSID.

8 REPLIES
Hall of Fame Super Gold

Re: Single SSID versus Multiple SSID

The question I would like to know is what bandwidth do you think the AP will be subjected to with each SSID.

I have serious doubts as to the decision/proposal to deploy AP with a single SSID against deploying an AP with multiple SSID.  (You can configure 1,024 SSIDs but 18 are supported.)

The alarm bells is that if you, for example, deploy three APs in an immediate area, the APs might auto-negotiate themselves their channel assignments:  1, 6 and 11.  All fine there, right?

This is the presumption that each APs broadcast multiple SSID.  Throw more APs in there because they're configured for single SSID and ... and ... I don't even know where to begin.

Yes, there are BW "costs" with an AP with single SSID and multiple SSID but I've never seen or even heard this factor to affect your wireless network.

In my line of work, I've never heard of anyone (even those with limited WLAN knowledge) propose this.  They are right when they said that configuring single SSID is easy but supporting this is a nightmare.

If you are using controller-based solution, you can specify which APs broadcast which SSID.  It's called AP Groups.

Can you elaborate, with a JPG diagram perhaps, the proposed design.  You are still in good shape because the APs are not yet deployed. 

Community Member

Re: Single SSID versus Multiple SSID

Hi

Thank you for your reply, I have attached a high level diagram, we have campus in each state single ground level where we will be using wireless hand held scanners to scan baggage, dual wireless controllers authenticating to Microsoft Radius/Microsoft CA Server. The campus is single level and we are deploying approximately 7 AP at each site.

The question of single SSID was asked by the scanner provider as it is easier for them to program a single ID for all scanners and not having to worry about which SSID belongs to which state during deployment or future device changes. My preference is to use unique SSId for each state campus the bandwidth is not great as they are only using telnet client to read barcodes and we have about 15 scanners in each campus.

I think I understand that each SSID is tied to a wireless channel hence by deploying single SSID you will have issues in matching channels in

the various campus is this understanding correct.

The design with the APS only using wireless scanners at this stage but later their maybe a requirement for laptops which we would put in a different SSID.

1. So in summary is the main reason for not deploying single SSID is the restriction it will place on the channel assignment in each state ?

2. How about security and troubleshooting would different SSID help for reporting or rogue access point detection, cant you report on rogue access points down to an AP level regardless of which SSID is being used.

Look forward to your response.

Thanks

Bill

CCIE 3906

Hall of Fame Super Gold

Re: Single SSID versus Multiple SSID

So in summary is the main reason for not deploying single SSID is the restriction it will place on the channel assignment in each state

No.  It's just a waste in resources.  It's like getting two switches for users to connect two different VLANs.  There are some exception-to-the-rule to use two physical LWAPs but this sure ain't it.  There are a number of WLAN posters who have bar code scanners and they have no issue sharing the LWAP with other SSIDs.

How about security and troubleshooting would different SSID help for reporting or rogue access point detection, cant you report on rogue access points down to an AP level regardless of which SSID is being used.

Right-o.  You have two ways of doing this.  By default, the WLC can detect rogue APs and clients.  The WLC can also "persecute" or contain the rogue APs and clients be sending massive amount of de-authenticate packet (aka de-auth packet).

Second way of doing this is to put a dedicated AP designed for wireless intrusion.  If you choose to go down this path, you will also need to use the Mobility Services Engine (MSE) and the wireless IPS (wIPS).

Scan baggages?  You sound like you work for the Australian Customs account.

The scanner manufacturer would like to know if one unique SSID (for the hand-held scanners) to be configured, like an SSID of "Symbols".  Sure, that's no problem.  You configure this ONCE, in the WLCs and/or WCS.  You can specify what channels the SSID can use.  Look at Woolies.  They have Cisco 1240s and they use Symbols hand-held scanners.  Look at Coles.  They have the same but they have different APs.  One to broadcast the hand-held scanner's SSID and other APs to broadcast others.

Hope this helps.

Community Member

Re: Single SSID versus Multiple SSID

Thanks for the response.

It sounds like we can assign the same SSID throughout the state for all the hand held scanner wireless LAN with no major issues. For

other devices we would put them in a different SSID on same AP's or use different AP's.

Regards

Bill

Hall of Fame Super Gold

Re: Single SSID versus Multiple SSID

Mate,

Remember, when you're dealing with WLC, you do not configure the APs.  You configure the WLC and the configs will be propatated to all the APs the WLC manages.

On the WLC, you can use up to 18 SSIDs but you can configure 1,024.

Currently, I have three SSIDs and one of them is for VoWLAN.

By the way, some hand-held scanners do not like non-broadcasting (hidden) SSID.

Hall of Fame Super Gold

Re: Single SSID versus Multiple SSID

Thanks for the ratings.

Re: Single SSID versus Multiple SSID

please correct me if I'm wrong, but you can ONLY have a total of 16 active SSIDs, not 18.

"Satisfaction does not come from knowing the solution, it comes from knowing why." - Rosalind Franklin
___________________________________________________________
Hall of Fame Super Gold

Re: Single SSID versus Multiple SSID

Nuts George.  I always forget this magic number.    (+5)

4513
Views
5
Helpful
8
Replies
CreatePlease to create content