900 sm loading

hello all we have been using a 900 cyclone omni at one of our locations and i now have more than 70 sm’s on that ap.

i am noticing some slow down issues and some problems with the further away sm’s having a hard time registering.

i want to move to sectorized panels and i would like to use 2 that would each cover 180 deg.

any suggestions?

Just curious, what do you have your control slots set at? Max range? What firmware? HWS or SWS? Downlink %? QoS in the SMs?

Right now I don’t have any suggestions on anetnnas for you.


http://www.mtiwe.com/data%5Cimages%5Cpr ... 015nh_.pdf

The problem I see with this is that customers to the sides might have trouble registering. Also, make sure this antenna has at least the same or more gain as your current omni.

To really maximize your AP here are some things you might do:
1. Balance the SM RF levels at the AP Sessions Page to all be within a 10dB window. This window will depend on where your noise floor is, and the signal level of your weakest SM.

For example, if your noise floor is -82, and your weakest SM is around -79, then making your window -75 to -65 should be good. Start with SM's that are over -65 and lower the transmit power on the SM in 1-2dB increments until they fall within your 10dB window at the AP sessions page. Ideally, they will all fall right in the middle at -70dB. The more diligent you are in this, the better that AP will perform.

2. Set control slots to 2. It will cost a bit of bandwidth, but there will be less retries due to contention. Contention is logarithmic, the more retries you have, the more contention you get, which causes more retries.....

3. Set burst size to a smaller number such as 2x the subscribed speed. Pages will still load quickly.

4. Shape the traffic. Use CactiEZ which comes with NTOP to get a look at how much P2P you have. If you have a lot of that, you would want to choke that down as the people using it the most seem to pay the least.

5. Set your max range just beyond the longest link.

6. Turn off 2x rate on all SM's except those that need more than 1.5Mbp and can hold 2x. I've noticed that even though they will link, it tends to be unstable as the SM keeps trying to switch to 2x.

7. On SM's without NAT, go to the Advanced Network Setting and turn on the following filters:
- PPPoE (unless you are using it)
- SMB (Network Neighborhood) (Customers don't need to see each other's machines)
- SNMP (This would be enabled on a case-by-case basis)
- Bootp Client (Unless you use DHCP to your customers)
- Bootp Server (nobody should be running a DHCP server on your network but you)
- IPv4 Multicast (You only want IP traffic on your network.)

8. Increase the bridge entry timeout to 500 minutes. This will lower the ARP trafficfrom the SM's a little bit. (it's not much anyway)

Thanks for the response jerry i am doing pretty much what you have outlined. i am fortunate that the noise floor is really low and i can get away with more than expected here.

i am blocking all of the ports you are suggesting and i have sculpted the rf on each of the sm’s to all about the -70 db range.

i am using 2 control slots but i have not put a burst in we advertise no capping so we are generally wide open.

the traffic shapping we are doing is in reality not much we do charge for overages with some warnings and it really has not been a problem.

the range on the ap is set to max because i need the max listening time for some of the sm’s we are in the land of the trees and with experimentation if i set the max range any lower i loose the higher db sm’s

2x is turned off except for the ones that can maintain a 2x constant and usually we swapp them to 2.4 if possible sometimes the trees and los dictate that we use a 900.

i will try your suggestion of increasing the bridge entry time out value.

again thanks and any more suggestions welcomed.

wow…we get some sluggishness from time to time on 20-25 SMs. We have 5 towers, a flat bridged network, and about 60 customers. We have 2 3 meg DSL lines. What are you feeding your network with?


What does the up/down utilization on those DSL’s look like? You have 6M down, but what do you have up? If you saturate your uplink you will notice sluggish response network wide.

If you were to grab an old PC and load it with CactiEZ, you could look at the traffic flow on all the AP’s, BH’s, Edge Switch, and Router.

Also, if you are not using the port filtering on the SM’s described below, you may be getting flooded with broadcast traffic which can easily eat up the majority of your network capacity.

Between P2P and broadcast traffic you could easily eat up all available BW on the network.

thanks jerry…yup…using those filters, cactiez, and pretty much everything else. i have a hard time figuring out what i want to limit upload to network wide but 256 seems a good number. question is…if i limit my 5.7 omni (which is serving all my towers which are 900 mhz) to 256k up and 0 burst, everyone will have access to 256 but no more, is that right?

both DSL lines support 384 up.

That seems to be a sweet spot…

I’d post some cacti info but i’ve got the box unplugged right now. We’ve just moved our 5.7 omni to a more centralized location and we’re stumbling right now on an entirely 900 mhz system. you can see our graphs at:


sluggishness seems to happen at the AP more than it seems to happen from the NOC or the 900 mhz AP at the noc.

(it happens on the first outter tower - i’m wondering if it could be the switch out there)

Are you limiting at the AP or the SM?