Orbi WiFi 7 RBE973
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RBK353 Increase bandwidth up to 50% by repositioning router and satellites.

Bockeman
Aspirant

RBK353 Increase bandwidth up to 50% by repositioning router and satellites.

RBR350, in AP mode + 2 satellites RBS350

Firmware version: V4.4.1.29_3.10.80
Hardware version RBR350
Hardware Type ORBI

 

The problem:
When I first connected up the Orbi router (RBR350) and satellites (RBK350) and measured the bandwidth I got a pultry 248 Mbps in one direction and 307 Mbps in the other direction when I was expecting close to the specified (theoretical) maximum of 1200Mbps.

 

Bandwidth measurement:
I am not using any test based on speedtest.net because that is dependendent upon the QoS provided by my ISP and a whole load of factors outside my control.
The physical connectivity is:

+----------+  1Gbps  +-----------+  WiFi 6 ax  +--------+  1GBps  +----------+
| server A |---------| satellite |- - - - - - -| router |---------| server B |
+----------+  Wired  |           |             |        |  Wired  +----------+
                     |           |             |        |
+----------+         |           |             |        |         +----------+
| server C |---------| satellite |             | router |---------| server D |
+----------+         +-----------+             +--------+         +----------+

I transfer a 1GiB file using the linux 'dd' command, from server A to server B, and then repeat in the reverse direction:

dd if=/dev/zero of=${server_file} bs=1M count=1024 iflag=fullblock
dd if=${server_file} of=/dev/null bs=1M count=1024 iflag=fullblock

which gives results like:

1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 34.5451 s, 31.1 MB/s
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 27.9948 s, 38.4 MB/s

I run equivalent tests between server A and server C, and also server B and server D to confirm the 1GBps wired bandwidth.

1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 9.25473 s, 116 MB/s
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 9.81479 s, 109 MB/s


giving 928 Mbps and 872Mbps. Thus I never expect to get the 1200Mbps theoretical, but I was expecting something close to 850Mbps.

I wrap the "dd" commands into scripts, repeat multiple times, take the average of 4 or more measurements, run between many combinations of server pairs (A-B,A-D,C-B,C-D) and so on.


The results:
Given the initial results of 248 Mbps and 307 Mbps, I very quickly moved the satellite from desklevel adjacent to the metal server enclosures and a brick wall. I then played with moving both the router and satellite to different nearby shelving, changing the orientation and changing every setup setting available.  As I changed each setting (like turning off AX, reducing transmit power, connecting/disconnecting the second satellite) I set a somewhat cryptic value (like third [shelf], "+s2" [with 2nd satellite]) to a variable that was recorded in the results.  I was also careful to eliminate outside factors, like when scheduled backups were in progress. I observed consideredable variation in bandwidth, even when not changing anything. I expected a period of time (20 mins) for beamforming.  I performed multiple resets of the router and satellites, but laterly avoided doing so because of the time wasted with no observable gain.  To date, I have recorded the results of over 15,000 1GiB file transfers.  The position of both the router and the satellite have by far the most dominant effect on bandwidth. Although there are 6 degrees of freedom of positioning (3 axis + 3 rotations), I quickly settled on moving each (router, satellite) along one axis, the distance from the front of the shelf.

  Orbi bandwidth measurements ranked according to highest average
  for all positions and settings
  (bandwidth averaged over 4 or more 1GB file transfers in each direction)
  router     satellite  Date                    Min     Average Max     Spread
  cm   setup cm  info                           Mbps    Mbps    Mbps    Mbps
  ---------- ---------- -------------------     ------- ------- ------- -------
  12.0 third  2.0 low   2024-03-22 12:00:58     612.000 646.000 684.800  72.800    1
  12.0 third  2.0 low   2024-03-22 12:03:00     606.400 642.500 680.000  73.600    2
  12.0 third  2.0 low   2024-03-23 14:02:15     609.600 642.400 683.200  73.600    3
  12.0 third  2.0 low   2024-03-24 17:02:43     607.200 639.400 693.600  86.400    4
  12.0 Vs2G4  2.0 low   2024-03-24 17:16:23     582.400 639.300 693.600 111.200    5
   8.0 third  2.0 low   2024-03-22 11:06:38     577.600 638.800 694.400 116.800    6
   9.0 third  6.0 low   2024-03-21 15:56:43     508.000 638.400 708.800 200.800    7
   8.0 third  2.0 low   2024-03-22 11:08:39     596.000 637.900 675.200  79.200    8
   0.0 third  3.0 low   2024-03-21 10:23:04     604.000 637.886 668.800  64.800    9
  12.0 third  3.0 low   2024-03-21 12:41:35     604.800 637.657 691.200  86.400   10
  12.0 third  6.0 low   2024-03-21 16:25:04     601.600 637.486 692.800  91.200   11
  12.0 third  2.0 low   2024-03-23 14:00:12     592.800 637.200 685.600  92.800   12
  12.0 Vs2G4  2.0 +s2   2024-03-25 10:09:45     592.800 636.900 680.800  88.000   13
  12.2 third  2.2 low   2024-03-23 20:52:58     602.400 636.000 676.000  73.600   14
  11.9 third  1.9 low   2024-03-24 11:40:50     573.600 635.800 680.000 106.400   15
  12.0 short  2.0 low   2024-03-24 16:52:34     522.400 635.200 697.600 175.200   16
  10.0 third  4.0 low   2024-03-22 14:15:33     605.600 635.000 680.000  74.400   17
   9.0 third  9.0 low   2024-03-21 19:59:54     599.200 633.829 693.600  94.400   18
  12.0 third  2.0 low   2024-03-24 17:00:40     579.200 633.800 668.800  89.600   19
  ...
  17.7 third  3.0 low   2024-03-21 14:01:14     424.000 446.400 478.400  54.400  801
  15.0 third  3.0 low   2024-03-21 13:16:36     329.600 445.657 472.800 143.200  802
  17.7 third  0.0 low   2024-03-20 23:32:28     404.000 443.314 457.600  53.600  803
  17.7 third  0.0 low   2024-03-20 23:11:10     373.600 441.771 494.400 120.800  804
  15.0 third  0.0 low   2024-03-20 22:09:12     380.000 441.200 496.800 116.800  805
  12.0 25%    2.0 low   2024-03-24 14:38:35     177.600 440.600 535.200 357.600  806
  17.7 third  0.0 low   2024-03-20 23:05:44     396.000 440.286 480.800  84.800  807
  10.0 third  0.0 low   2024-03-22 20:26:44     427.200 439.900 472.000  44.800  808
  17.7 third  0.0 low   2024-03-20 23:21:37     394.400 438.971 477.600  83.200  809
  15.0 third  3.0 low   2024-03-21 13:00:49     402.400 438.000 461.600  59.200  810
  17.7 third  0.0 low   2024-03-20 23:27:05     398.400 435.886 457.600  59.200  811
   3.0 third  0.0 low   2024-03-20 20:11:27     381.600 434.571 520.800 139.200  812
   3.0 third  0.0 low   2024-03-20 20:05:57     204.800 427.714 496.000 291.200  813
  10.0 third  0.0 low   2024-03-22 20:23:54     393.600 423.600 440.800  47.200  814

  Top ranking of bandwidth in different positions:
  ----------+---------------------------------------------------------
  Satellite |  Router position (from edge of shelf) cm
   position |    0.0     3.0     6.0     9.0    12.0    15.0    18.0  
         cm +---------------------------------------------------------
        0.0 |  465     780     295      54      33     750     711    
        3.0 |    9     690     212       6       1     789     299    
        6.0 |  305     574     391       7      11     157      50    
        9.0 |  411     191     698      18     727      57     202    
       12.0 |  493                                                    
  Orbi bandwidth measurements ranked according to highest average
  for positions within a few mm of optimal
  (bandwidth averaged over 4 or more 1GB file transfers in each direction)
  router     satellite  Date                    Min     Average Max     Spread
  cm   setup  cm  info                          Mbps    Mbps    Mbps    Mbps
  ----------  --------  -------------------     ------- ------- ------- -------
  12.0 third  2.0 low   2024-03-22 12:00:58     612.000 646.000 684.800  72.800    1
  12.0 third  2.0 low   2024-03-22 12:03:00     606.400 642.500 680.000  73.600    2
  12.0 third  2.0 low   2024-03-23 14:02:15     609.600 642.400 683.200  73.600    3
  12.0 third  2.0 low   2024-03-24 17:02:43     607.200 639.400 693.600  86.400    4
  12.0 Vs2G4  2.0 low   2024-03-24 17:16:23     582.400 639.300 693.600 111.200    5
  12.0 third  2.0 low   2024-03-23 14:00:12     592.800 637.200 685.600  92.800    6
  12.0 Vs2G4  2.0 +s2   2024-03-25 10:09:45     592.800 636.900 680.800  88.000    7
  12.2 third  2.2 low   2024-03-23 20:52:58     602.400 636.000 676.000  73.600    8
  11.9 third  1.9 low   2024-03-24 11:40:50     573.600 635.800 680.000 106.400    9
  12.0 short  2.0 low   2024-03-24 16:52:34     522.400 635.200 697.600 175.200   10
  12.0 third  2.0 low   2024-03-24 17:00:40     579.200 633.800 668.800  89.600   11
  12.2 third  1.8 low   2024-03-23 19:38:02     513.600 633.700 699.200 185.600   12
  12.0 2.4/4  2.0 low   2024-03-24 14:17:57     575.200 632.500 686.400 111.200   13
  11.8 third  1.8 low   2024-03-23 19:09:41     545.600 631.800 677.600 132.000   14
  12.0 Vs2G4  2.0 +s2   2024-03-24 21:23:52     518.400 631.500 696.000 177.600   15
  12.0 third  2.0 low   2024-03-24 14:04:51     547.200 631.400 676.000 128.800   16
  12.0 third  2.0 low   2024-03-23 23:16:06     603.200 630.900 668.000  64.800   17
  12.0 Vs2G4  2.0 +s2   2024-03-25 10:07:42     592.000 630.000 673.600  81.600   18
  12.2 third  1.8 low   2024-03-23 19:35:59     495.200 629.500 690.400 195.200   19
  ...
  11.8 third  2.2 low   2024-03-23 20:22:50     465.600 563.800 660.000 194.400  231
  12.0 no_ax  2.0 low   2024-03-24 16:09:57     434.400 559.100 605.600 171.200  232
  12.0 third  2.0 low   2024-03-23 23:20:40     287.200 555.400 684.000 396.800  233
  12.0 third  2.0 low   2024-03-23 23:27:50     292.000 554.300 694.400 402.400  234
  12.0 Vs2G4  2.0 low   2024-03-24 19:18:56     418.400 554.000 612.800 194.400  235
  12.0 no_ax  2.0 low   2024-03-24 16:14:34     445.600 548.200 627.200 181.600  236
  12.0 third  2.0 low   2024-03-22 22:47:46     440.800 545.000 597.600 156.800  237
  12.0 third  2.0 low   2024-03-23 23:25:23     404.000 536.200 657.600 253.600  238
  12.0 third  2.0 low   2024-03-22 22:40:53     428.000 531.600 602.400 174.400  239
  12.1 third  1.9 low   2024-03-24 12:06:39     217.600 514.100 694.400 476.800  240

  Top ranking of bandwidth in different positions:
  ----------+-----------------------------------------
  Satellite |  Router position (from edge of shelf) cm
   position |   11.8    11.9    12.0    12.1    12.2  
         cm +-----------------------------------------
        1.8 |   14              24              12    
        1.9 |            9      65      78            
        2.0 |   26      42       1      32      55    
        2.1 |           32      43      84            
        2.2 |   64              56               8    

 

Conclusion:
I increased the backhaul bandwidth by about 50% purely by adjusting the positions of the router and satellite with 1mm precision.

Message 1 of 5
FURRYe38
Guru

Re: RBK353 Increase bandwidth up to 50% by repositioning router and satellites.

Good to know.

 

What is the size of your home? Sq Ft?
What is the distance between the router 📡 and satellite(s)🛰️? 30 feet or more is recommended in between RBR 📡 and RBS 🛰️ to begin with depending upon building materials when wired or wirelessly connected.
https://kb.netgear.com/31029/Where-should-I-place-my-Orbi-satellite ‌‌🛰

Message 2 of 5
Bockeman
Aspirant

Re: RBK353 Increase bandwidth up to 50% by repositioning router and satellites.

Distance between router and satellite about 5m (15ft) through stair case wood and a single skin brick wall.

 

Floor area approx 80m^2 (860 sq ft).  But this is surely irrelevant because I am not using the WiFi to connect to mobile and IoT devices.  The only thing I was interested in and tested was the backhaul bandwidth.

 

I'm puzzled as to why the recommendation is more than 10m (30ft) because surely the further away, the weaker the signal strength and presumably lower bandwidth.

Message 3 of 5
CrimpOn
Guru

Re: RBK353 Increase bandwidth up to 50% by repositioning router and satellites.


@Bockeman wrote:

I'm puzzled as to why the recommendation is more than 10m (30ft) because surely the further away, the weaker the signal strength and presumably lower bandwidth.


This recommendation is based on the premise that the point of purchasing a mesh WiFi system is to provide WiFi coverage. (Which does not appear to be relevant to your situation.)

 

Imagine if WiFi units were 1 ft. apart.  That would increase the area provided with strong WiFi signals by so little that it might not be measurable.  Also, devices might get into a pattern of switching back and forth when (temporarily) they sense that one unit is stronger than the other.  If the units were 50 ft. apart, the areas of good coverage would probably not overlap at all, giving an increase of 100%, but the backhaul link would not function.  At least 10 ft. of separation creates a significant increase.  The "sweet spot" appears to be about 30 ft. (balancing increased coverage against strength of backhaul signal).

 

Message 4 of 5
FURRYe38
Guru

Re: RBK353 Increase bandwidth up to 50% by repositioning router and satellites.

All this very relevant. And not everyone has a brick wall in between as well, which will also be a factor. 
Glad you got some improvements though.

 

Message 5 of 5
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