Wireless Access

Occasional Contributor I

Controller says 120 Mb/s, but only 12 Mb/s work ...



I'd just stumbled upon a problem which I don't quite get ...


I got a 600 series controller (Alcatel-Lucent 4306) running software version for the purpose of a single straight (secure jack) link.


Connected to the controller is one AP92 which is on a roof of a building pointing with a panel antenna to another AP92 about 600m's away on top of another building ...Besides that, the LAN and seperate Management access is fed to the controller via one  trunkport and VLAN's.


On the IP site, only the internal network for the AP's communication and Management access are defined, one VLAN for transmission is declared but without IP's basically only so that I could set this on the Mesh Point as access VLAN ...


RSSI is pretty stable at around 32 -34, noise floor on both ends is between -87 dB and -85.

It's configured to run 40Mhz-HT with one spatial stream and out of the 150 Mb/s there is usually 120 to 135 Mb/s available according to the controller.


It's been running now stable for a couple of months and we haven't really utilized that link but as we now wanted to, we figured the absolute max is 12 Mb/s in both directions, that is if I switch the tunneling off and use bridging, otherwise it's just below 11Mb/s.


the Ethernet ports are checked for speed and errors and there is nothing, on a RF-side it seems to drop down sometimes do 24 Mb/s but according to the packet counter less than 5% ...


We initially suspected other network equipment causing the restriction, but even with 2 Laptops connected on both ends without any other equipment it's doing the same and that we tested with a variety of different methods, e.g. flood pings, secure copy, http downloads, a.s.o


There are two funny things which might have something to do with it, but I am not sure:


- if I get the link to its limit and I ping the remote mesh point, the pings are dead stable at 1-2 ms ...

     I mean on a conguested link running that low they should vary more than that ...

- now even if there is no Policy Enforcement License, and I am not certain if it has something to do with it, but if I

  set one of the CP Rate Limits to it's maximum value 400 Mb/s, and I take the 'available Bytes', sum them all together and multiply by 8, yep I got to something 12m  ..


Datapath Bandwidth Management Table Entries
Contract Types : 
   0 - CP Dos 1 - Configured contracts 2 - Internal contracts
Flags: Q - No drop, P - No shape(Only Policed), 
       T - Auto tuned 
---  --------  ---------  ----------  -----------  -----------------
     Cont                       Avail   Queued/Pkts 
Type  Id   Bits/sec  Policed    Bytes    Bytes      Flags
---- ---- --------- ---------- ------- ------------ -----
0    1      5000192          0   19532       0/0     
0    2      2000128          0    7813       0/0     
0    3    400000000          0 1562374       0/0     
0    4      2000128          0    7813       0/0     
0    5      2000128          0    7813       0/0     
0    6      2000128          0    7813       0/0     
0    7      2000128          0    7813       0/0     
2    1            0          0       0       0/0     
2    2            0          0       0       0/0     
2    3      2002944          0    7824       0/0    QT 


all available bytes = 1628795 *8 /1024  /1024 = 12.42 Mb/s ... the abosulte and pretty steady max I could sent through with bridging and concurrent flood pings was 12.2 Mb/s


Does anybody have an idea whether that has something to do with it or is just a coincident and if this is valid how I can influence this value or whether I am missing something else ?


Aruba Employee

Re: Controller says 120 Mb/s, but only 12 Mb/s work ...



What are you using to test the throughput?  I would use something like iperf and make sure you are not using the default settings. Here is a good client side setup for iperf that will fill the pipe, replace with the server's IP and 5001 with whatever port you choose:


iperf -c -P 1 -i 1 -p 5001 -w 1024K -f m -t 10


The output of  'show datapath bwm' you posted shows that you are not hitting any of the contracts with your traffic, you would see some numbers under 'policed' if you were. 


For outdoor links I usually test both 20mhz and 40mhz channels, I regularly see 20mhz beat 40mhz outdoor for throughput through the link.  

Marcus Wehmeyer
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