ISP: Number of SMs on 1 AP to get good results

Is there a common formula to get the max. number of SMs on 1 AP with a certain dsl-connection?

My parameters:

I have the option to get DSL 6.000 (means 6.016 kbit/s down and 576 kbit/s up). I want to provide a 1024 kbps/s down and 128 kbit/s up).

I work with 1 Advantage AP and normal SMs.

What is the formula to calculate the max. number of SMs to get a good connection without complaining customers??

Thank you for your help.


The wireless equipment has nothing to do with this decission.

How many megabit customers can share a 6 megabit connection? I would think you could fill an entire AP (200 SMs).

But only if you truely have a dedicated, guaranteed connection.

- Is your DSL connection capable of 6 mbps, or is that just what they advertise?
- Does the acceptable use policy of your ISP allow you to resell your bandwidth?
- Is your DSL connection a dedicated service? (IE: could you max out the bandwidth 24/7 without the ISP caring?)

If all answers are yes, then you should be ready to rock!

You should be fine supporting about 25 clients. More if you use a real router after the DSL router.

Here’s our formula:
3 7down/1up DSL connections
every residential get his SM rate limited to 384down with 10000 burst and 128up with 4000 burst. This gives impressive numbers for the primary thing customers will use for QOS: download tests! (see

We HAD to install a real router between our backhauls and the DSL router. Our low-power DSL router kept crashing, rebooting, locking up etc. We bought a Mikrotik license (L5) for about $100, installed it into an old P3-1000 with 128MB RAM, Dual NICS, and BAM, reliable and fast Wireless DSL. The Mikrotik also allowed us to create a firewall rule for P2P applications, which, when coming from multiple sources, choke a DSL router purple.

Important to note we only use this for residential customers, who are casual users.

Business users, gamers, and customers needing good uploads shouldn’t go with the setup. Fortunately at most of our main towers we have two feeds, the DSL and the NxT1 connections. Based on our configurations, we easily switch to whatever connection is most appropriate.