SM Majorly Confused

Ok first thanks in advanced for reading this. I have tried to do my homework, but whatI am seeing just doesn’t make any sense to me. We are starting a 900Mhz Canopy system in a very rural area with a noise floor around -90. Pictured below are the graphs to give you a visual of the problem we are having.

If set the values on the QOS tab of the SM to anything but the defaults then I get a awful lot of choppyness into the connection and the quality isn’t good. what I have done is setup a MySpeed server at our main location and access it from my house, so the hop is SM > AP > BHS > BHM > Test Server, all on the same private subnet. I truly believe it is something between the SM and the AP.

Our Company needs to be able to sell diffrent services plans like 256,512,1.0,1.5 but if it get intermitent like this then customers are going to start compaining. I know I could set the burst higher but we would like to get about as much out of what bandwidth we have as it isn’ cheap up here.

PLEASE HELP, we are about to deploy our system next wekk and start signing up costomers.

512 Limited Data Rate up/down, burst set to 0

Full Rate Badwidth & TCP Pause


What type of AP’s, SM, and BH’s are you using?
What Firmware does everything have?
Have you did speed tests from BHS, therefore bypassing the AP and the SM?

No I havn’t tested directly with a BHS, everything was on and I upgraded everything to 8.2.2 last night.

The reason I believe its not somewhere else in the link is because if I set the SM to full bandwidth, it works just fine. But If I set the SM to 1024 up/down with 0 for burst, it works like crap. I get the 1024 sometimes, but it downloads up to 1.5 then pauses then starts, you get the idea and you can see it in the picture above. It does this with all the SM’s i have tried it with, is this just the way the canopy system works? or am I missing something in the configuration here?


Little more info I just setup a diffrent test from, it appears to only happen to the downlink, the uplink is very smooth, but when it downloads you can see it pause the needle just sits there and bounces.

My concern is that when a customer does a speed test as we all know they will that there going to see this and think something is wrong.


Correct me if I’m wrong here but I don’t think you want your burst set to 0. I believe that if you don’t want to use bursting then you need to set your burst and sustained data rates the same. If your burst is set lower then your sustained rate, then the burst allocation will set your speed and not the sustained rate. Here’s a section from the user guide:

7.1.10 Interaction of Burst Allocation and Sustained Data Rate Settings

If the Burst Allocation is set to 1200 kb and the Sustained Data Rate is set to 128 kbps, a data burst of 1000 kb is transmitted at full speed because the Burst Allocation is set high enough. After the burst, the bucket experiences a significant refill at the Sustained Data Rate. This configuration uses the advantage of the settable Burst Allocation.

If both the Burst Allocation and the Sustained Data Rate are set to 128 kb, a burst is limited to the Burst Allocation value. This configuration does not take advantage of the settable Burst Allocation.

If the Burst Allocation is set to 128 kb and the Sustained Data Rate is set to 256 kbps, the actual rate will be the burst allocation (but in kbps). As above, this configuration does not take advantage of the settable Burst Allocation.

I Have tried that also, same result. I have tried just about every combination that I can think of and I still get the same delay. One interesting thing is that I said the uplink was fine, well now that the weekend is over and I’m at the office, If I run the same test to my house at a server I have there. The downlink is bad and uplink good, so now I am super confused.


HAve you tryed setting your CIR to the desired rate along with the Sustained and the burst?

yup, I spoke with canopy support today, and they basically said you have to have a burst, but i know that jerry and others have run without one before. So i’m at a complete loss, im afraid that if we set the burst high enough to eliminate this problem that its going to hurt us because it will eat up bandwidth way quicker and we won’t hardly have an oversubscription ratio at all. Even if I set all values exactly the same the problem still occurs, Matt at motorola basically said that is the way it works that it downloads at full speed and then pauses to get to the right average. I have a hard time believing this as I don’t see anyone else on the boards complaining about this. What does everyone find a good burst value to be? and what kind of oversubscription ratio do you get out of canopy? We currently have a 3mb pipe.


While it may not be the kind of fix you where hoping for we run our subscribers using PPPoE which allows you to control the speeds outside of the canopy settings, eg leaving all SM’s to allow max speed but PPPoE limit set to whatever speed is required.

As mentioned before this may not work with your network setup… There are a couple where we run a point to point connection between offices via a canopy network and have manually set the speeds 2Mbit by setting the sustained rates to 2048 and burst rate to 250. This setup was tested and give a sustained 2 Mbit.

If your going to set the speed in the sm unit,then we had to use a small burst to achieve a good speed test

64kbps Sustained up load and 300 burst
512kbps Sustained download and 800-1000 burst

This gave us a good smooth speed test. You just need to play with it.

How many customers are you planning on putting on 3 meg?

Just remember if they want to down load a 300 meg file there going to
download it if it takes all day, or 10 min’s and keep your bandwidth tied
up while there downloading.

This is what we used when we first started did a good job but it’s only good for 128 customers and 4 meg

We found that out of a hundred customers you might have 5 that abuse our network and needed to be slowed down

Thanks for all the responses.

I don’t know how many customers were going to get on the 3mb, We don’t really know what to expect but I am thinking we should get upwards of 150 - 250. With the caveat that most people around here are going to take our cheapest plan. I know that the only other provider of broadband in our town put 200 on a single T1 before they finally gave in and got more bandwidth. we are in a really rural area, population 600, and that is going to help also, because farmers and ranchers like my father-in-law usually don’t due big downloads.

We plan on monitors very closely and when we need more bandwidth we will just get more, bandwidth is cheap right :smiley: