Hi all!
Now the picture I see : it is about 20mbps at sector's downlink throughput and 95% frame time used.
Which means it's gonna become total hell in the evenings and even worse at new years eve.
MCS 10 is ~80% at the downlink.
So as I can understand - 20mbps is my maximum? Not even funny
Hi,
Could you attach a screenshot please to give us a little bit more information?
Thank you.
@beeonline wrote:Now the picture I see : it is about 20mbps at sector's downlink throughput and 95% frame time used.
MCS 10 is ~80% at the downlink. So as I can understand - 20mbps is my maximum?
Hi. Well, a sector's potential capacity is governed by several things, including the MCS which you can get to clients. If you are mostly only getting MCS 10 most of the time, that will substantially limit the sector's capacity vs if you were getting MCS15 on everything. Also, the channel width, and the number of packet retransmissions, and a bunch of other factors also limit how much the sector is capable of.
MCS10 is QPSK 3/4 - so that's a whole lot less efficient than 12 QAM, 64 QAM or 256 QAM is.
MCS 15 - 64-QAM 5/6
MCS 14 - 64-QAM 3/4
MCS 13 - 64-QAM 2/3
MCS 12 - 16-QAM 3/4
MCS 11 - 16-QAM 1/2
MCS 10 - QPSK 3/4
If you can embed screen shots of your CONFIGURATION - RADIO, and your MONITOR - WIRELESS and MONITOR - PERFORMANCE screens, that will help us help you. :)
You have your AP locked to MCS 10, change that to max of MCS15
And,yes I know ch width will limit the bandwidth, but still, at 20mhz MCS10 ideally can reach up to 50, but all i get is 20mbps, even without peaks
There is a reason why it is locked, I have high interference and % is spread between 10-15, and some amount in MCS2, I had to lock in MCS10 to prevent MCS jump and retransmissions.
And also, this does not explain low downlink. As the table says, MCS10 can provide up to 50mbps in 20mhz. I get no even half of it with low retransmission rate and 0% drop.
UPD. My bad, the MCS table says up to 39mpbs with Long guard interval. Well, could be half of it, but no peaks...
Also I have QOS with MIR enabled, but why would it cause hight % of frame time usage
MCS10 has a RAW/PHY maximum of 39mbps. That includes protocol overhead. Actual IP traffic is going to be about 75% of that, which is 29mbps. And you're doing a 75/25 DL/UL ratio, which leaves about 22mbps for DL.
Set the max MCS back to 15, identify the SM(s) that have a poor DL MCS and address the interference that's affecting those SMs. Poor MCS in the DL direction means interference at the SM. If all of your SMs have poor DL rates there must be another device on the same channel near the location of your AP.
@dkeltgen wrote:MCS10 has a RAW/PHY maximum of 39mbps. That includes protocol overhead. Actual IP traffic is going to be about 75% of that, which is 29mbps. And you're doing a 75/25 DL/UL ratio, which leaves about 22mbps for DL.
Set the max MCS back to 15, identify the SM(s) that have a poor DL MCS and address the interference that's affecting those SMs. Poor MCS in the DL direction means interference at the SM. If all of your SMs have poor DL rates there must be another device on the same channel near the location of your AP.
Might i ask where you found that information? I assume that number is specific to 20mhz channel on 2g. Is there a chart which also says the other MCS as well as channel widths and 5g?
I like http://mcsindex.com as a quick sheet to get the raw PHY throughput per MCS.
Dmitry
@beeonline wrote:There is a reason why it is locked, I have high interference and % is spread between 10-15, and some amount in MCS2, I had to lock in MCS10 to prevent MCS jump and retransmissions.
And also, this does not explain low downlink. As the table says, MCS10 can provide up to 50mbps in 20mhz. I get no even half of it with low retransmission rate and 0% drop.
UPD. My bad, the MCS table says up to 39mpbs with Long guard interval. Well, could be half of it, but no peaks...
Also I have QOS with MIR enabled, but why would it cause hight % of frame time usage
There is a throughput graph in the ePMP user guide. The attached screenshot is for 75/25, 5ms, long guard interval. You are using long guard, and 2.5ms frames, so you will have less than the highlighted throughtput for MCS10.
