control slots

what is the function of control slots?

In all AP of my network I must set the number of control slots (how say the manual) based on how many SM register to that AP?

thanks ... trol+slots ... trol+slots ... trol+slots

This BBS has a search function

I saw the link and the manual but they not answer to my doubts…


Are you have problems?

I want know if it’s only necessary set the value how say the manual or there are other configuration

Sorry if I came accross as rude the first time…

The purpose of control slots is to manage the timing of radio transmissions to and from the SMs. This assures that multiple SMs are not trying to transmit to their AP at the same time.

The more SMs you have connected to an AP, the more control slots you need.

When do I need to add another control slot you ask? Look in “RF CB Stat” under Expanded Stats of the AP. Are you getting any indiscards or outdiscards? If so, you should add a control slot.

Hope that helps,

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Hi, thanks a lot for the explanation…

In my RF CB Stat I have 0 indiscards and 411 outdiscards, but on the AP I have only 4 SM I need take the number of control slot to 1??

actually the number of control slots is 0 and i’m using hardware scheduling

I would bump the control slots up to 1, yeah.

Something else though, all APs of the same band at a location need the same number of control slots.

IE: When one AP gets enough customers for another control slot, you need to bump up the control slots on the entire cluster.

I noticed when I changed my control slots from 3 to 4, the downlink rate in the speedtests went from 100% to 99%. Is this normal?

systemseven wrote:
I noticed when I changed my control slots from 3 to 4, the downlink rate in the speedtests went from 100% to 99%. Is this normal?

That sounds like a fluke to me.

Increasing your control slots reduces the number of slots that are used for auctual data transmission, so your max throughput will decrease a bit. On the link tests, you would see this as reduced uplink/download rate -- not a reduction in the efficiency of the link.

well i learn something new everyday but i have 52 subscribers on my 900 mhz system what would you suggest i sent my slots to it was on 0 and i had 0 incoming and 7000 out going so i set it to 1 should i go to 2 or 3 ?


After enabling hardware scheduler, go to the AP’s Configuration page and enter the appropriate number of Control Slots from Table 5. With hardware scheduling, one parameter, Control Slots, replaces the 6 slot parameters used with Software Scheduling.

Table 5: Control Slots vs Number of SMs on AP
Number of SMs Registering to AP Control Slots Recommended
1 – 10 = 0
11 – 50 = 1
51 – 150 = 2
151 – 200 = 3

Recomended is the operative word there. That table is a good stating point, but it depends on usage and throughput more then number of subscribers.

IE: you will be able to put more then 10 SMs on zero control slots if they are light users – emial checking, light surfing, etc.

But get 50 warez-heads pegging your bandwidth 24/7 and there’s no way 1 control slot will be enough.

that’s true, it really depends on the traffic at given AP.
Sometimes you can see <10 clients on the AP requiring more CS to avoid packet discards.