Does Qos in GPS Synced AP and poor signal to SM affect the system???

I need a  scientific ;-) reply about:

1- AP GPS synced 

2- MS with a poor signal (AP, in closed loop, tells MS to push in xxdB) with 10MCS UPLINK  3MCS DOWNLINK.

If we give high priority in "QoS" to the  MS does this affect the system, in wich terms?

Is it valid anyway if QoS is not aenabled?


Anyone out there have an answer?


Hey OC, could you please clarify your question... I don't think anyone has responded because we don't understand what your question is.


If you five a poor signal cpe higher priority than the rest, the ap will give that sm more airtime and less to the regular priority. If the SMS don't matter on there performance you'll be fine, but if your trying to improve the situation by giving this one sm high priority your going to harm the performance of the regular priority SMs while that on is busy. I would suggest improving its signal conditions if you can. Using a reflector or a connectorized sm with a larger dish if possible.


Hi OC.  I agree with Eric - I think that the lack of responses is probably/mainly due to people not understanding what your question is exactly.  But, let me take a stab at it. :)

Cambium ePMP does have an 'air fairness' scheduler, so unlike pretty much every other brand, a client with low signal can't drag the entire AP down, and can't dominate the entire AP at the detriment of everyone else.  The ePMP Access Point will give a 'time slot' to each SM, and if a SM/CPE has a low signal or a good signal, they don't start 'out competing' other SM's like other brands do.

However, that being said - the overal capacity of an Access Point is still a function of signals and qualities, so your best bet is to improve this guys signals.  If you have an AP with 10 clients and everyone is a -57 and they are QOS to 5Mbit each, then it'll work great because there is 50 Mbit of airtime and the AP can do 10x 5Mbit, and these clients can keep up. On the other hand, if everyone is a -75 and you want to give 20 Mbit to each client, then the AP wil have to spend extra time slots  to try to get that throughput to each client, and the overall signals and rates simply don't add up.  THere isn't going to be 200 Mbit of throughput at -75 signals, so you can't do 10x 20Mbit and expect every client to be abel to run at full capacity at the same time....   so something will have to give when you have low signals.

So - it's kinda a yes and no answer.  Yes, if you have one low signal client, and if the combination of him and everyone else doesn't exceed the potential capacity, then it can work OK.  But, if you turn that low signal client's QOS up higher than his MCS's can really do, then something will have to give.  You can't get blood from a stone and there is only so much capacity to go around, and that capacity is lower with low signal clients.

Again, the best solution IS always to improve the signal - that's always going to be the best solution if that's possible.



can anybody explain WHY the priority configuration is in the SM and not centrally managed by the AP?

If the MIR is configured at the AP, why the priority can not be centrally managed too? Is this a wifi legacy parameter?



the QoS profiles are set via radius or by the CPEs.   the AP only has the definiton information to which the CPEs request.   You can't set the specific speed for a specific CPE directly though the AP. you've got to tell the CPE to request profile  1,2,3,4 ect.    The AP just knows what to do with that profile number. Same thing for telling the AP what speed the CPE will get. if your wanting to do it through radius, I'd have to check on some definition information, but I'm sure cambium support can walk you step by step on defining those options if they are available. 

@ roanwifi

Actually traffic priority is settable on both: AP (for downlink direction) and SM (for uplink direction). AP is managing the queues OTA as it controls all the traffic in cell. In fact it is easier and less complex to configure uplink QoS on SM - you do not want to create offline database on AP, right?


I have such "offline" database which is in the radius server... If I can manage all connection attributes from a central site, this is the best solution of course. It has no sense to centrally manage connection attributes (ip, speed, caps, etc..) and have to enter on the SM to adjust another connection related parameter..

Best regards


Many thanks Chris. thats cleared my doubts.