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04/17/2015
Radio Shootout Pt 1 - AC Lite vs. Brand M
Description

Mim-AC.JPG

I was initially going to compare the AF5X with the Brand M radio (in the picture above) so that everyone could see how the two really compare.   But once I did some baseline throughput testing on the bench, it became obvious that Brand M wasn't really in the same league as the AF5X, and was really more like the AC radios (which is actually what it is - it even says "a/n/ac" in one of it's wireless mode selections).   Below is a quick look at the max speeds of a RocketM, and AC Lite, an AF5X (actually on early firmware, so the ones people are getting now are actually faster) and Brand M.   This is a quick and dirty baseline test - the tests farther below were much more thorough and better set up, but all the radios were treated equally for this first one.

BaselineShootout.png

What became immediately obvious was that except with an 80MHz channel the Brand M radio, comparing apples-to-apples (with just one of it's 2x2 radio channels operating) is significantly slower than the AF5X, and still slower than the RocketAC Lite.   

So at this point I abandoned the idea of head-to-head testing (at least for throughput) with the AF5X, which really outclasses the Brand M, and instead stick with the ACs.

 

One thing that should be finally put to bed here - if anyone out there still thinks there's some magic going on inside the Brand M radio for it's "160MHz channel" other  than effectively two AC radios in one box, here's the proof - an AirView of the radios actually running:  

B5cDualRadio.png

If you look at the areas directly adjacent to the two 40MHz channels, you can see how much IM junk is generated in the PA - this is on the bench, so there's no interference from outside radios.

 

Anyway, after this I just concentrated on comparing it to an AC Lite.   Following is a series of automated tests comparing the AC Lite and the Brand M radios.   These are all using iperf in tcp mode, with 10 streams each, and with a complete tests running in each direction at once, so this is testing actual throughput both directions simultaneously for each radio.   Note that the PHY rate (dotted line) is the actual theoretical hardware encoding rate possible at that MCS and channel width, and the actual throughput of the radios is always lower than that - often much lower.

Throughput_bidir_R5AC-LITE,MIMO-B5C,['1x20']1429223748.pngThroughput_bidir_R5AC-LITE,MIMO-B5C,['1x40']1429223942.png

Throughput_bidir_R5AC-LITE,MIMO-B5C,['1x80']1429223960.png

You can see that in 2x2 mode at 80MHz the Brand M is faster than the AC Lite - at that channel width, the AC Lite is at the edge of it's chipset's capabilities, plus it was designed to do more narrow channels.   And who has clear 80MHz chunks of spectrum anyway?

 

Since the Brand M radio has the capability (as seen in the AirView above) to run as two 2x2 MIMO radios on two different channels, and combine the data streams together, the analogous setup for an AC radio is to use two discrete radios, each on it's own channel.   So this was done also (the setup actually used an EdgeRouter in load balancing mode to create the two streams for the two radios, and then another one to recombine them on the other end):

Throughput_bidir_R5AC-LITE,MIMO-B5C,['2x20']1429223709.png

You will note in the above test that the Brand M radio shifted speed part way through the test.   I saw this kind of behavior in other areas too - changing power output to see what effect that had on throughput, I found I could never quite get back to the performance level I initially saw.   And some times the performance would drop off after the radio heated up - this may be indicative of some thermal management issues in their power amplifiers - the actual quality of the PA , or maybe they just need a bigger heatsink...

Throughput_bidir_R5AC-LITE,MIMO-B5C,['2x40']1429223662.pngThroughput_bidir_R5AC-LITE,MIMO-B5C,['2x80']1429223987.png

Note that in the dual 80MHz case the AC Lites are faster than Brand M, unlike in the single 2x2 test before.  My guess is the PA is reaching the limits of it's IM cababilities trying to linearly amplify the two separate frequencies, and therefore the modulation rates go down.

 

Since the test was already set up, here are the AC Lite's results for all the other channel widths it can do:

Throughput_bidir_R5AC-LITE_1429224656.png

And here it is with dual radios:

Throughput_bidir_R5AC-LITE_1429224655.png

Now it's legitimate to ask if using two complete AC radios and an EdgeRouter Lite on each end is a fair comparison in the real world.   Well, economically, a pair of Brand M radios costs $1678, vs $740 for 4 AC Lites plus two EdgeRouters, a less than half the price of the Brand M radios alone.   And yes, to make this work you'd need 2 more antennas for the ACs, but this is a pretty corner case solution anyway - where but in the middle of nowhere or over a very short link are you going to be able to do this (especially at 80MHz channels) and in those cases you can probably do better with AF5s or AF24s anyway.

 

So what's the upshot of all this?   Well, things don't look so good for the Brand M radios so far in this shootout...

 

Part two will look at some other radios (plus these two again) and how they fare in interference situations. 

Jim

Comments
by
on ‎07-23-2015 01:24 PM

Jim,

 

Can you please point me to a config to set up a dual backhaul link with an ERL on each side?  I have a lab set up and have been fumbling through load balance config examples for dual WAN balancing but what I need to do is combing/balance 2 ptp RF links that are already and running.

 

Thanks,

 

JW

by
on ‎05-12-2016 06:05 AM

Hi guys,

 

I do not agree 100% with this test. tested in a real environment the aforementioned radio and mimosa B5c fared better in these conditions REAL. in without interference environment is one thing, now in real life is another.
use very AF5X in our network and AF5, and now a few more B5c due to the high that radio bandwidth capacity.
We spoke by burning problems with the rocket ac lite and other problems that we had with B5c of mimosa. who knows and properly confgura the Rados know what I'm saying. but it is a great test to have as a base, now will work or not for each provider is another story.

by
on ‎12-08-2016 12:48 AM

Tnx eejimm

 

 

 

 

 

 

M_Brand_Shoot.jpg

by
on ‎12-08-2016 04:15 AM
por
3 horas atrás

Tnx eejimm

 

 

 

 

 

 

by
on ‎12-12-2016 12:49 AM

Still facing some performance issue (high PER even in cleanest enviroment causing lower modulation)  and most importand high sensitivy of the ethernet interface (link state/flapping).

 

 

Did you notice it has over the air frame losses (drop frames) ?