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Just curious. We have up to 10 per AP. I've read that some clients have trouble with too many BSSIDs, and was wondering if anybody has seen problems related to having too many active SSIDs.

Also, if you have 2 APs with the same 10 SSIDs, does that equal 20 BSSIDs?

Thanks,
Andrew

For testing purposes, we easily run that many per AP on one of our test networks. But we also are running only one or two clients per SSID (usually one), and we are not doing throughput, or roaming, tests at those times. So I can't tell you what it would do to performance. Our client devices don't have problems with it.

By defiinition, each BSSID is unique, so yes 10 BSSID's + 10 more = 20 BSSIDS.

Not so with SSIDS obviously - in that case, just count the number of unique network names (i.e. SSID's).

I'm sure there are several people in this forum that can give you a more detailed answer.

After 6 SSIDs you created a perfect storm. Not only does the AP have to broadcast 10 beacons per second for each SSID on each band, imagine the probe responses when each client does requests. At 10 SSIDs the majority of your traffic is just management, and not data. 10 SSIDs is fine for a test network, but in production you would find it very hard to sustain throughput with so much traffic.

Some handheld wireless clients, their tables get filled up when they see too many BSSIDs and they cannot associate (I'm looking at you, iPhone!).

In modern enterprise wireless LANS, you should be able to group clients by encryption type and use other methods to separate traffic.

Also bear in mind that, by default, beacons are sent at the lowest data rates supported by the AP - normally 1 or 2Mbps. This really eats into the bandwidth available for useful traffic, so it's definitely a case of less is more with regards to number of SSIDs.

Has anyone done the math or really measured the impact and traffic amount created with 10 SSIDs?
Some facts to support the above comments sholud be valuable.

Is it not possible also to sent multiple SSIDs in the same beacon? Larger beacon frames but only one!
Anyone read the standards lately?

Thanks in advance.

Martin

A colleague of mine wrote a paper on a similar situation. I cannot post attachements to this forum, but I will post the numbers:

"12 virtual APs (BSSIDs), 100 clients in a given coverage area and with 3 APs on the same channel, the management traffic is almost 35% of the overall traffic at a data rate a 1 Mbps. This is because beacons, probe requests and probe responses are transmitted at 1Mbps data rate as per the 802.11b/g standards.
The bandwidth utilization for management traffic however is still well below 10% when the number of SSIDs is less than or equal to 3."

"The effects are more pronounced in real world deployments with multiple floors and signals from neighboring offices bleeding into the coverage area. A client would now hear other APs on the same channel from neighboring WLAN deployments apart from the APs on its own valid WLAN network. As a result the client would hear 4 ? 6 APs at any time. The bandwidth utilization for control traffic shoots up to 55% for 12 SSIDs at a data rate of 1Mbps assuming that there are at least 6 APs in the RF vicinity of each client."

Was this it ?

http://airheads.arubanetworks.com/article/aruba-radio-corner-impact-multiple-ssids

Yes, but does not have graphs or pictures that are cited in the article; old forum migration victim.

The discussion about all the MAC layer overhead and medium contention overhead produced by having numerous SSIDs/BSSIDs is a spot on and should probably be a CWDP type scenario question. The best way to separate traffic is too use one SSID for voice, one SSID for guest users, maybe another for other handheld devices such as WLAN barcode scanners and finally the main SSID for laptops.

The best way to further segment users on the main SSID is to leverage returning RADIUS attributes to assign groups of users to unique VLANs and firewall policies.

If running on a g-only network the the lowest spped would be 6 MHz an the percentage of non-data will be lower or??