Hi there MikrotiK guys

I need some help here...I just started my 5ghz link. here are the parameters:


Band 5GHZ
AP - RB 133c + atheros card 50mw
CLIENT - RB 133c + atheros card 50mw
BRIDGE MODE (point to point only)
5km distance
80 clients behind the RB (behind the RB there is a linux router...after it - clients)

AP antenna - Panel Antena (18dbi i think) Cable to the RB - 3 meters long.
CLIENT antenna - Satelite 90cm. Cable to the RB - 4 meters long.


The two RBs connect on 18mbits but the real speed i managed to reach is around 5mbits. The ping between the routers gets really bad after 3mbits of traffic. I have a 18mbit connection to the internet and i cant manage to deliver it to the clients (and they are becoming angry ).

I need at least 10mbit of traffic for my network.

Can anyone help me with some tip of how to reach some better speeds in cheaper way .
I thought about buying another SATELITE antenna but decided to ask here first. Are the cables from antennas to the RBs too long??

Seeking for your answers...

Regards Ventsi

First question: Does this link have clear Line of Sight? 5GHZ won't go through much.

Second question, what are the signal levels and noise floors?

For the most part, real traffic throughput maxes out around 50% of what the radios link up at. To get 10 megs of throughput, the radios should be linked with a reliable signal at 24mbps. Line of sight with those antennas should be able to get you linked at 54megs which should get you in range of your 18megs...

One thing to note, the RB133c isn't a very powerful board, so check your processor when transferring data.. if the CPU is maxed out, that becomes your bottleneck.

Aboslutley CLEAN line of sight...but a tested the connection in my room before deplying the RBs and i accomplished 20-24mbits traffic...I wonder is the problem in the Panel antenna or in the Cables connecting the RBs to the Antennas...

I think that if the traffic can reach 24mbits in my room...it can reach that speed outdoors too?!?!??

And i forgot... signal levels

-67dbm/-80dbm (i am really a newby here and dont know much about all this but the links sometimes connects on 18mbits/12mbits and the rates must improve )

other problem is that even with low traffic passing between the RBs. ping is between 10-30.
I used 2.4Ghz A Ppoints EDIMAX with 2 California Antenas. Then i reached 8mbits traffic and 1-3ms ping reply. But it got too crowded with wireless APs on 2.4Ghz so i decided to make 5Ghz link. And now...it is worst than before..

Should i enable Nstream and what it does?

Regards, Ventsi.

The rb 133 is just not fast enough to process anything faster.
The max I have seen using the rb133 is ~7M Up and 7M down.

-67dbm/-80dbm.

That doesn't seem like it should be right. Signal should be close to the same on each end. If it isn't, maybe you have a bad card, or maybe it is just too noise on one end. Have you tried different channels?

Yes i DID. But i am afraid about the PANEL antenna...is it possible?
And maybe thi 4 meters long cable to the SATELITE antenna and the 3 meters cable to the PANEL antenna...?!!?!

I a sure they can take much ore traffic...coz the test i made at home reached 24mbits one way. If i have half of this i will be happy.

And the signal levels difference could be coz of the antenna right? It is weaker or something?
Hope u know the answer...

Thanks in advance

Regards Ventsi.



P.S.: And what about Nstream??? What exactly it does and should i enable it?

Most things like cables and antennas are bi directional. Having a stronger antenna on one end would help the signal both ways. same with cable loss, it should reduce the signal by the same amout regardless of which way it is going.

Having the signal be that much difference between directions might mean that you have a card that went bad, it could be interference, or it could be misaligned antennas, but the first 2 are the most likely.

Put some bandwidth on the link and report what the CCQ is in the wireless status.

Nstream shouldn't be necessary or make a huge difference on a PTP link of this length. It would mostly just consume more CPU, which might be part of your problem to begin with.

Joe

Thanks for the help...i am going to test it tonight and see the result...just waiting the later hours so clients dont complain

I will post results after the test.

status: running-ap
band: 5ghz
frequency: 5200MHz
noise-floor: -102dBm
overall-tx-ccq: 44%
registered-clients: 1
authenticated-clients: 1
current-ack-timeout: 60
current-distance: 60
nstreme: no
current-tx-powers: 6Mbps:18,9Mbps:18,12Mbps:18,18Mbps:18,24Mbps:18,
36Mbps:17,48Mbps:16,54Mbps:14
notify-external-fdb: no



Haven't changed channels yet... what is ccq???

OK...changed channels...the best i could manage to reach is 600kb/s and good ping (i mean acceptable for now...) but i need MORE bandwith .

1 thing i noticed is that link works only at 5180 - 5280 MHZ...
if i try 5700 it will not connect...is this becouse of 1 of the cards...(one of them is not atheros...different models. i just remembered it.)

Well I think you really need to focus on getting better signal. I still think something is wrong for the signal to be that different between TX and RX. -80 isn't very good signal. I would start by swapping cards and see if that makes a difference.

Next, I would try higher gain antennas. If you want to get anywhere close to the 18megs your connection is, you should aim for signal strengths in the -50's. For example, for the CM9 to link at 54mbps, it needs at least -71 signal. You should give yourself some headroom to allow for fluctuation. I like 10db of margin, so that would be a minimum of -61 signal.

Thanks for the tip...when i change the cards i will write here the result but...right now i cant make it becouse i am 250km away to study...maybe in about 10 days i will do it.

I really appretiate the help u r providing me Jcremin. Thanks alot.

Change the rb133c with at least 133 or 532, or you won't be able to use your 18 mbit connection at full capacity.
133c to 133c - -70/-72 db, most is 6/5 mbit for me, in a relatively clear area on 5 ghz, point to point.

Put 2 pc with same signal, and output is around 10-12 mbit both ways ( 20-23 one way). ( that was not that cheap ... )
Also,

overall-tx-ccq: 44%

is very low.
I see good links only well above 70%. The rest are dropping some packets.

I found it also helps for me to activate /ip packing for the wireless interfaces. You should start at least with that, and see if any improvements.