Canopy Lite:
Throughput = 512 kbps
Burst = 0 - 768 kbit
How can I deliver a minimum of 200 kbps for download and up to 300 kbps for navigation? What are the settings on QoS page?
Sustained Downlink = ?
Burst Downlink = ?
Is there any other configuration required beyond these up?
Thank you.
set sustained down to 200
set sustained up to 300
set your burst values to 0
keep in mind that because of tcp overhead you may not see those exact speeds. if you want 200Kb on the down as a minimum then you may have to massage the sustained rates to get your desired speeds.
Excuse my total confusion.
Now, reading what I wrote, I realize that was wrong.
What I meant was:
When the costumer go navigating, do it on 300 kbps (here I think it’s Burst) and when he is downloading, do it on 200 kbps.
Maybe:
Sustained Download 220 kbps
Downlink Burst 350 kbit.
?
Well it’s still confusing but…I’ll take a shot.
Download
Sustained = 200
Burst = 350
This will give the client a sustained download of 200Kbps with burst on the down to 350kbps.
So the client could POTENTIALLY see a 350kbps download speed.
However from experience. When the BURST is set that low the client very rarely sees the burts speeds.
Frothingdog.ca wrote:
However from experience. When the BURST is set that low the client very rarely sees the burts speeds.
Please help me with your experience!
What do you mean is that 350 is a low value for a good customer experience?
We should use at least how much? The maximum: 768 kbit (canopy Lite)?
How can i calculate the cost? Over sustained downlink or over Burst or with an average?
Could you give me an explanation of the Burst and your use?
I am very grateful.
Leaving the BURT to 768 would probably be best but that depends on a number factors regarding your network…ie up stream capacity, over subcription rate, targeted market penitration…etce…etc.
The higher burst values will make the web surfering experience for the user appear faster then it actually is. The impact on bandiwdth useage should be minimal.
Install a few clients and give them the 768 burst as a trial, and graph their usage with RTG. This should give you a rough idea of the amount of bandwidth a user with a 768 burst would use on a daily basis. Then you can crunch your numbers again to see if it’s solution that would work for you.
The Burst setting in Canopy is not actually a speed - it’s actually a size. If you set Burst = 350 and Sustained = 200, then the customer’s radio will transfer the first 350 KiloBytes at maximum rate before falling back to a sustained speed of 200 kilobits per second. The idea here is that with bursting you get the customer off the air/network as soon as possible. Canopy lets you decide how much is appropriate. I have good results with setting the burst to about 1 Meg to allow for most web pages to load.
If you actually want to limit the speed at which the burst occurs then you will require some outboard form of control like rate limiting within a router.
Our problem is basically information.
Our problems:
- Link dedicated with the least variation possible: sell 256/256 kbps give 256/256 kbps (Down/Up)
- Link “residential” with large downloads at 220 kbps and 330 kbps on navigation: with this purpose, what the value of Burst - 350, or 500, or 768?
- Understanding of Burst:
- If i have a Downlink Burst of 300 kbit, means that i will have 300 kbit being sent to 512 kbps (the maximum speed of Lite)?
- What happens when I have a Burst of 768 kbit? The package of 768 kbit will be launched to 512 kbps? It will be divided, 512 at once and the rest then?
- When the Burst is sent it must pull itself together (filling the bucket), now the costumer is browsing at the speed of Sustained Downlink? At this moment, the costumer will not navigate below the Sustained Downlink, due to the filling of the bucket?
- What are the effects of Burst:
- Burst > Sustained Downlink => ?
- Burst < Sustained Downlink => ?
- Burst = Sustained Downlink => ?
Since I’m already very grateful for the information.
Thank you all.
You are pretty much correct. On your Lite platform, the Burst will transfer however amount of kilobytes (not bits, so multiply by 8) at 512 Kbps or whatever speed you get for downlink from the Link Capacity Test tool, and then any further data will get throttled to the Sustained Rate.
I am not sure of the internal timers - one thing I have often wondered is how close together can bursts be to always get the maximum rate. How intermittent does traffic need to be to count as ‘sustained’? I think someone much smarter than I (like Jerry on these forums, lol) knows these values.
So, lets do some math for your scenario:
Burst size = 350 KBytes
Sustained = 200 Kbps
So if your customer starts to download a full 1 MByte file, the first 5.5 seconds or so ((350 bytes * 8) / 512 kbps) at the full speed, and the remainder will get throttled to 200 Kbps and take about 26 seconds to complete. Total time will be about 31.5 seconds.
Now, if you double the Burst Size to 700 KBytes, they will burst at 512 Kbps for about 11 seconds and the rest will take about 4.7 seconds at 200 Kbps. This almost doubles the user experience (15.7 sec to download 1 MB) for small files like web pages with little impact on the AP, but since the burst size is still pretty small larger transfers should not impact the performance any differently than before. An additional bonus is that most end-user traffic is intermittent, so the likelihood of several people trying to burst at the same time to the point where it causes a problem is very minimal. In fact in some cases this will improve the AP’s congestion as well as there are fewer long, sustained transfers occurring.