2700/3700 AP's - Calculating per AP device support for HD WLAN Deployment

[aarontoddatkins]

Hi,

We are starting to see requirements for the new 802.11ac AP's to be deployed for Voice/Video applications (Lync, Jabber) and I want to know the "rule of thumb" for calculating the number of devices per AP (2700/3700 models).

In the past 802.11b/g/n, we used 15-20 devices per AP, but the new model have multiple radios and can support much higher device counts.

Normally, we require a pre-site survey before ordering the AP's, but I still need a simple calculation for budgetary quotes.

Example: 

New customer greenfield building. 

Coverage area:  2 floors

Number of users: 230

Expected number of devices per user: 2

For a budgetary quote, we would pad the number of AP's by 20%-30% to provide for difficult coverage areas.

Todd

[Leo Laohoo]

A few months ago, we tested 30 Chromebooks associated to a single AP3700 (not running 802.11ac) and we streamed a 5 minute HD video from a server.  The link between the switch to the server (multiple hops) is 1 Gbps.   Result:  Passed with flying colours.  No issue.  No jitter.  NOTHING.  

Data rates:  18 Mbps as Mandatory; 1 Mbps to 11 Mbps DISABLED; 12 Mbps and above set to Supported.

But this is NOT a rule-of-thumb I would recommend.  I personally would still stick by 8 wireless client doing HD per AP.  

[Scott Fella]

That is a tough question to answer. I still like the 20-25 per AP, but with Lync and Jabber, you still need to QoS that traffic and make sure the COS to DSCP mapping is properly set. I remember testing with the 1252's and 802.11n and the customer wanted to upload up to 4GB of video in 30 minutes. Well we were able to achieve that with only 4-5 clients per AP.  So that being said, how much does your user utilize video or voice when using Lync. How many devices per, also depends on the client devices.  Stable clients work well in high density but some clients don't.  I have seen ipads and Macbook Pros have issues when there are a lot of clients associated to a given AP.  Code, supplicant and drivers can also play as a factor in this. Bottom line, it's what's the limit before users experience starts dropping. 

Scott