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Dual Nstreme - Strange Behavior

Posted: Wed Dec 27, 2006 6:43 am
by bokili
First I setup 2 independent nstreme links, before I start with NSTREME2.

P4 on each end, 5 SR5 cards in every P4.

I choose 2 cards on each end, connect them with 29dBi Grid Antennas..

Signal with every Tryout (SR5 to SR5 with 29dBi, over 65Km distance)
is about -68 to -75 on both antennas and links.

Nstreme Single Bandwidth Test:

It gives approximately about 16-22Mbit/sec in one direction, 9Mbit/sec in both. DATA Rate is 12Mbit/sec.. Better bandwidth with 24 and 18 data rate but, it can heppend for link to be disconnected for 1 sec sometimes and this can result in lost packets, so I choose 12.

Framer policy: exact
Framer limit: 2500
Turbo Mod: tried with various frequencies
polling: turned on

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Conclusion:

Bandwidth is excellent with 0% lost packets in all cases.
MAIN PROBLEM is LATENCY. It can be very erratic: 1. 1-20ms with low internet real traffic (pppoe tunels); 2. 1-50ms and more with internet traffic up to approx. 1.5Mbit/sec in each direction. Also very erratic.

In comparation to WDS and Bridge mode, single nstreme have poor latency performance, but better bandwidth.



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NSTREME DUAL
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Nstreme Dual setup with the same cards, antennas, framer limit and policy. Signal -68 to -75 on both RX and TX..

Tried with various frequencies.

When i start it, it was something that i didn't expect to see.
WOW, latency constantly up to 1.3ms..

Bandwidth: send= about 22M, receive about 19M...
Both= 7/7

Excellent results. But...

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PROBLEM: IT WORKED EXCELLENT FOR 5 DAYS. THEN ONE DAY, bandwidth significiantly dropped, up to 1Mbit/sec in both directions (up to 4 in one direction). Latency also, 1-20ms erratic and not constantly anymore. Setup is the same, nothing was touched.

I thought that frequencies are not clean, so I tried with other ones, which are at least 200MHZ separated. But no impovement, just worse...

Also, I tried again to use NSTREME SINGLE ON BOTH antennas, and single nstreme setup works perfectly again, of course with erratic PING TIMES, WHICH I HATE :)

I really do not understand what can be the problem. Somebody, to help ?

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I was forced to back to single NSTREME with good bandwitdh and poor latency performance (erratic).

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NOTICED ONE PROBLEM WITH SINGLE NSTREME WHICH CAN OCCUR:

if you use bridge mode and wds on one part of the network, and station wds with nstreme on other part of the network: You can have strange behavior of network where you have bridge and wds links, sometimes they can lose integrity until you separate network with stations wds.

Solution is also NSTREME DUAL, but as you see it doesn't work properly for me.

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If somebody have comments, please post it right now.

Posted: Wed Dec 27, 2006 2:28 pm
by uldis
what was your configuration for the dual nstreme?

Posted: Wed Dec 27, 2006 5:30 pm
by bokili
Uldis,

What you mean exactly, I posted hardware setup. And Nstreme2 setup also.

Do you mean which freq or ?

Or this:

interface wireless nstreme-dual> print
Flags: X - disabled, R - running
0 R name="nstreme1" mtu=1500 mac-address=00:15:6D:50:05:4A arp=enabled disable-running-check=no
tx-radio=wlan1 rx-radio=wlan2 remote-mac=00:15:6D:50:16:B8 tx-band=5ghz-turbo
tx-frequency=5680 rx-band=5ghz-turbo rx-frequency=5320 rates-b=1Mbps rates-a/g=6Mbps,9Mbps,12Mbps,18Mbps
framer-policy=exact-size framer-limit=2500

Posted: Wed Dec 27, 2006 9:47 pm
by believewireless
We've seen a similar problem with Nstreme2. Usually rebooting the boxes fixes the problem. We find that only one side of the link will connect and the other won't. Mess with settings until you are blue in the face and it still doesn't come up. A few days later, try again and it's fine.

NStreme will work fine on both frequencies by itself so it's not a matter of interference. (200MHz separation, etc, etc.)

Posted: Wed Dec 27, 2006 10:03 pm
by bokili
Yes, yes.. single nstreme works fine on both frequencies.

No, rebooting doesn't fix problem here..

Posted: Thu Dec 28, 2006 12:31 pm
by uldis
First try to use regular 5gzh band and framer-policy=none after that if you have stable link you can iprove the settings, enabling the framer policy and increasing the framer-limit, enabling 5ghz-turbo mode, use higher data rates...

Posted: Thu Dec 28, 2006 12:58 pm
by BurstNET
First things first...

What frequencies are these 5 cards operating on in the P4 systems?
We have done extensive testing, and found that cards on 10mhz of spectrum need 40mhz of spacing, if in the same system case, otherwise there will be latency, packet loss, thoughtpuut loss, and overall degraded performance.
There only need be 20mhz of spacing if cards are seperate cases at the same location/POP. We tested using SR5 cards from Ubiquitti which they claim do both transmit and receive at 10mhz if set for such.



SMA

Posted: Thu Dec 28, 2006 11:10 pm
by bokili
It's separated more than 200mhz each...

You will not believe it..

Today it works, like before..

Let's see what will be tomorrow...