Thanks Chris & Chris.. for asking the question I had and answering it. :)
For Chris T. For those of us for who 10db is till too hot... Do you think Engineering can come with with some sort of a insert that we could possibly install in the wave guide .. which could say dampen 3-5 db worth of Tx Power ? I think such 'disc' would be very helpful for the short links like the one Chris & others have .. Regards Faisal Imtiaz Snappy Internet & Telecom 7266 SW 48 Street Miami, FL 33155 Tel: 305 663 5518 x 232 Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net > From: "Chris Trout" <ch...@mimosa.co> > To: af@afmug.com > Sent: Monday, January 30, 2017 9:00:31 PM > Subject: Re: [AFMUG] B11, TDMA, and TCP > Hi Chris, > Yes, there is a hardware limitation. The diode detectors used in the PA to > control Tx power lose dynamic range at low power. I’ve raised your request to > our engineering team for future product designs. > Chris Trout > Mimosa Networks, Inc. > From: Af <af-boun...@afmug.com> on behalf of Chris Wright > <ch...@velociter.net> > Reply-To: "af@afmug.com" <af@afmug.com> > Date: Monday, January 30, 2017 at 8:23 AM > To: "af@afmug.com" <af@afmug.com> > Subject: Re: [AFMUG] B11, TDMA, and TCP > In my case, even 10dB output on both sides is still too hot. Is the 10dB > minimum > power output a hardware limitation or is it possible you can throw that on the > feature requests pile? > Thanks, > Chris Wright > Network Administrator > From: Af [mailto:af-boun...@afmug.com] On Behalf Of Chris Trout > Sent: Sunday, January 29, 2017 5:39 PM > To: af@afmug.com > Subject: Re: [AFMUG] B11, TDMA, and TCP > Hi Faisal, > TPC is designed to do this automatically, but so far we have limited how much > change it can make, and are still tuning its behavior in cases of unequal > power > per side of the link, very low RSSI on one or more chains, and very high RSSI. > Some of these changes will be included in the next backhaul firmware release. > In our experience, targeting 30 dB of SNR per chain results in the best > performance, so for now we recommend adjusting Tx power to get near that > level, > and then let TPC manage fine adjustments from there. > Chris Trout > Mimosa Networks, Inc. > From: Af < af-boun...@afmug.com > on behalf of Faisal Imtiaz < > fai...@snappytelecom.net > > Reply-To: " af@afmug.com " < af@afmug.com > > Date: Thursday, January 26, 2017 at 10:36 AM > To: " af@afmug.com " < af@afmug.com > > Subject: Re: [AFMUG] B11, TDMA, and TCP > Hi Chris, > What is the optimum SNR or aka the sweet spot. > Which actually leads to another question which I have... > On my link, I had to manually reduce TX Power to 10dBm (lowest possible) in > order to end up with a SNR of 35/37... > Can we possible see this being done by TPC vs a manual power decrease ? > Regards. > Faisal Imtiaz > Snappy Internet & Telecom > 7266 SW 48 Street > Miami, FL 33155 > Tel: 305 663 5518 x 232 > Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net >> From: "Chris Trout" < ch...@mimosa.co > >> To: af@afmug.com >> Sent: Thursday, January 26, 2017 12:32:32 PM >> Subject: Re: [AFMUG] B11, TDMA, and TCP >> Great point, Tim. I have updated our documentation. >> Transmit compression starts at 27 dBm Tx power on backhaul products. TPC >> backs >> off from this value automatically if SNR allows. >> Mimosa backhaul radios are capable of associating at relatively high Rx power >> levels (between -30 and -20 dBm). However, higher power levels cause the >> receivers to saturate, and this increases the error vector magnitude (EVM). >> For >> this reason, Mimosa recommends designing links with -30 dBm or lower received >> power to avoid saturation. >> To optimize RF performance, adjust Tx power on the AP while monitoring both >> Rx >> power and EVM on the Station side of the link. Tx power should be set to a >> value that results in the lowest EVM value. >> The only reason why some compression or saturation may be acceptable is in >> the >> case of low SNR, which has a larger effect on overall performance. >> Chris Trout >> Mimosa Networks, Inc. >> From: Af < af-boun...@afmug.com > on behalf of "Hardy, Tim" < >> tha...@comsearch.com > >> Reply-To: " af@afmug.com " < af@afmug.com > >> Date: Wednesday, January 25, 2017 at 6:47 PM >> To: " af@afmug.com " < af@afmug.com > >> Subject: Re: [AFMUG] B11, TDMA, and TCP >> Chris, >> It might help us design these properly if we knew what the saturation levels >> were. We have these for most other radios. >> Thanks, >> Tim >> From: Af < af-boun...@afmug.com > on behalf of Chris Trout < ch...@mimosa.co >> > >> Sent: Wednesday, January 25, 2017 9:22:14 PM >> To: af@afmug.com >> Subject: Re: [AFMUG] B11, TDMA, and TCP >> The PHY (Layer 1) is affected by EVM and PER which cause changes in >> modulation. >> The MAC (Layer 2), where TDMA lives, makes use of the PHY but does not >> change it >> directly. >> Changes in the amount and direction of traffic across the link do affect EVM >> and >> PER, however. >> It is likely that the PHY rate is more stable on your link at 1300 Mbps >> (MCS7) >> than at 1560 Mbps (MCS8), and Auto TDMA is reacting faster to changing >> conditions since it sends a shorter duration of packets for training the PHY >> rate. >> As others have recommended, reducing power will avoid saturating the >> receiver, >> and reduce (improve) EVM. I think that is what we may be seeing here on a >> very >> short link. >> Chris Trout >> Mimosa Networks, Inc. >> From: Af < af-boun...@afmug.com > on behalf of Chris Wright < >> ch...@velociter.net > >> Reply-To: " af@afmug.com " < af@afmug.com > >> Date: Wednesday, January 25, 2017 at 1:55 PM >> To: " af@afmug.com " < af@afmug.com > >> Subject: Re: [AFMUG] B11, TDMA, and TCP >> Traffic Split set to Auto: >> PHY 1300/1300 >> Traffic Split set to 75/25, 8ms window: >> PHY 1560/1300 >> Anyone can see why one should prefer setting the Traffic Split to 75/25 – it >> provides more bandwidth in one direction. >> Chris Wright >> Network Administrator >> From: Faisal Imtiaz [ mailto:fai...@snappytelecom.net ] >> Sent: Wednesday, January 25, 2017 12:35 PM >> To: af@afmug.com >> Cc: Chris Wright >> Subject: Re: [AFMUG] B11, TDMA, and TCP >> Hi Chris, >> I want to compare something with my link... >> Can you please share what's the listed PHY rates were on your PCN for the >> link. >> Regards. >> Faisal Imtiaz >> Snappy Internet & Telecom >> 7266 SW 48 Street >> Miami, FL 33155 >> Tel: 305 663 5518 x 232 >> Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net >>> From: "Chris Wright" < ch...@velociter.net > >>> To: af@afmug.com >>> Sent: Wednesday, January 25, 2017 11:21:12 AM >>> Subject: Re: [AFMUG] B11, TDMA, and TCP >>> Power is already at the minimum (10dBm) on both sides. 2.2km link. >>> Chris Wright >>> Network Administrator >>> From: Af [ mailto:af-boun...@afmug.com ] On Behalf Of Faisal Imtiaz >>> Sent: Tuesday, January 24, 2017 9:56 PM >>> To: af@afmug.com >>> Subject: Re: [AFMUG] B11, TDMA, and TCP >>> > SNR 41, 42, 41, 41 >>> Turn down your power, and bring the SNR in the 30-35 range... >>> it will improve thruput and allow for the higher modulation. >>> Regards. >>> Faisal Imtiaz >>> Snappy Internet & Telecom >>> 7266 SW 48 Street >>> Miami, FL 33155 >>> Tel: 305 663 5518 x 232 >>> Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net >>>> From: "Chris Wright" < ch...@velociter.net > >>>> To: af@afmug.com >>>> Sent: Wednesday, January 25, 2017 12:41:37 AM >>>> Subject: Re: [AFMUG] B11, TDMA, and TCP >>>> Firmware 1.4.4 >>>> SNR 41, 42, 41, 41 >>>> Flow Control had no effect so it remains disabled for now. >>>> Sent via mobile phone. >>>> On Jan 24, 2017, at 9:05 PM, Faisal Imtiaz < fai...@snappytelecom.net > >>>> wrote: >>>>> What version for firmware is on the radio ? >>>>> and What your SNR on the two chains (both directions, i.e. 4 readings). >>>>> I can tell you that we do not see the behavior you are describing below... >>>>> But I can also tell you that we had to do some 'tuning' on settings >>>>> including >>>>> flow control .. >>>>> our B11's plug into netonix Switches.... >>>>> Regards. >>>>> Faisal Imtiaz >>>>> Snappy Internet & Telecom >>>>> 7266 SW 48 Street >>>>> Miami, FL 33155 >>>>> Tel: 305 663 5518 x 232 >>>>> Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net >>>>>> From: "Chris Wright" < ch...@velociter.net > >>>>>> To: af@afmug.com >>>>>> Sent: Tuesday, January 24, 2017 8:02:58 PM >>>>>> Subject: [AFMUG] B11, TDMA, and TCP >>>>>> According to Mimosa, I should be telling my customers that if they’re >>>>>> using the >>>>>> most popular metric in the world for testing internet speeds, they’re >>>>>> doing it >>>>>> wrong (I concede that while this may be technically correct, my >>>>>> customers – and >>>>>> yours too – don’t do technically correct very well.” >>>>>> When TDMA is set to 75/25, 8ms window, MAC Tx/Rx is 980/290. This gives >>>>>> me as >>>>>> much Tx bandwidth as I require for peak times, but no one client IP can >>>>>> download more than 20mbps of TCP traffic (from my speedtest.net at the >>>>>> edge, >>>>>> nor anyone else’s beyond my edge). >>>>>> When TDMA is Auto, MAC Tx/Rx is 780/780 (lower Tx, which is undesirable >>>>>> as it’s >>>>>> 100mbps shy of what I need during peak hours), but TCP throughput per >>>>>> client is >>>>>> greatly increased (150+mbps). >>>>>> So I’m in a pickle. Either my scrupulous customers can get those coveted >>>>>> speedtest.net results they love seeing as they run them every thirty >>>>>> seconds >>>>>> ad-nauseum at the cost of overall Tx capacity of the link. Or I give >>>>>> myself >>>>>> some headroom in link capacity but the fastest speeds my 100mbps clients >>>>>> can >>>>>> see is 20mbps. >>>>>> What’s even stranger is that client upload seems unaffected. I can upload >>>>>> 150+mbps from my test on the link no matter what TDMA is configured. I >>>>>> hit up >>>>>> Mimosa’s chat support was as chipper as they were unyielding in their >>>>>> idea that >>>>>> I should test in a way that caters to the B11’s shortcomings. I’ve been a >>>>>> Mimosa fanboy for a while now but boy am I feeling burned right now. >>>>>> Chris Wright >>>>>> Network Administrator
