NS2, Tranzeo and MikroTik 532A/XR2 AP

RouterOS Wireless Networking
1

This is also being posted to Tranzeo and Ubquity.

Sunday, I replaced an old,(6 years in service!), Hermes I based AP, (base mounted radio, top mounted 1W amp, 150ft LMR-400) with a top mounted RB532A 5.8GHz backhaul and 2.4GHz AP.

The radio card for the AP is an XR2 into a 9db Comet omni. 8ft of LMR-400. Set in B/G mode. Preamble set to both. CH9. All other settings, except ESSID are default.

Connected to this AP was quite a mixture of clients, including:

Tranzeo CPE-80, CPE-90, CPE-200, CPE-CPQ
Lucent Hermes I client
Senao CB3, EOC-3220
Ubquity NS2

After the change.

Sig strength reported by the mt range from -51 to -92
Thruput on the AP tripled. tests to my laptop while standing at the base exceeded 7Mb/sec which saturated my fiber. tests before the change could not exceed 2Mb/sec.
The Tranzeo cpe-80 would not stay connected. it would connect and disconnect on a 5 sec cycle. replaced it with an eoc-3220
The B clients, all 6 of them, have stayed connected since power up.
The NS2’s, all 5 of them, seem to disconnect/reconnect in a block once or so a day.
some of the remaining G clients, 4 of them, seem to disconnect/reconnect in a block in 8-9 hours
the remaining G clients, 4 of them, are all over the place. from 18 hours to 1 hour. I would not read too much into this however, as some of my users power their radios down when not in use.
The NS2’s are all reported with anything from 1Mbps to 54Mbps as the tx rate but are always reported with 1mbps as the rx rate
The NS2’s are all reported with a radio name. Nothing else shows a radio name.

The things I wounder about are:

radio names not being reported for Tranzeo/Senao radios
NS2’s showing a 1Mbps rx rate all the time
NS2’s disconnecting/reconnecting as a group

any comments would be appreciated.

2

Make sure your hardware retries are set to 4. I have had good success lowering both SR2 and XR2’s to a fixed 23dBm and you’ll want to disable rates above 24 megs as it lowers the power.

Evaluate those borderline (-92) clients, you want to have everyone at a target -64 to -72 signal.

What is the TX rate set to on the NS2’s?

3

The NS2’s are all set to select their Tx rate automatically.

The -92 client, an old tranzeo unit, preforms flawlessly. 3Mb/s. I am forced to believe that the -92 reading that is displayed is false.

Changing the hardware retries has no effect that I can see. overall Tx CCQ remains varying from 85% to 95%.

Cutting the AP’s Tx rate dramatically reduces thruput by 30% or more. It also induces ping instability.

I am very wary of changing the XR2 card’s Tx power setting off of default. I managed to destroy a few SR cards in the past by playing with that…

4

Adjusting the TX power should only be used when turning the power down on a radio. If you burned up SR2’s you either didn’t understand the offset or you were overdriving the card. There should be no negative effect by disabling the speed rates above 25 megs.

5

Well, the main effect of disabling the 36M,48M and 54M Tx rates on the AP is to make all of my b/g tranzeo clients report 24M instead of 48M or 54M. These clients then see reduced download speeds of about 30%. from 5-7Mb/s download to 4-5Mb/s download. Not a huge difference, but noticeable.

The ping instability only shows up under heavy AP load and is much worse when the 36M, 48M and 54M modes are disabled.

I’ll give the power reduction on the AP’s Tx side a shot, however, my tests show that all my clients are receiving the AP with out any problems.

6

You are where I was a few years ago… Did this myself… From AP-1000’s with lucent card and amp to routerboard and xr2’s

Get the Hermes client(s) out of the system. Get the Tranzeo 80’s out of the system. It will be a bit unstable until you do.

All your remaining clients should be able to handle short preambles after update.

Update all your Tranzeo’s firmware. Follow the instructions on Tranzeo’s website. Some of the older units MUST be taken to the newest firmware in steps.

Update the NS2 and NS2L gear to 4.0.1 firmware.

You may want to turn on RTS/CTS on the clients and AP. I do and I use 256 bytes as my setting.

That should stabilize things.

The NS2 gear will disconnect and reconnect about every 23-25 hours as long as the Tranzeo gear is on the AP with it. Something to do with the Tranzeo timeout bug. Since the blip only lasted a couple seconds, I never tried to trace it down.

I’d then work on getting the Intersil 2.5 gear out of the system. (all the ‘B’ 200mW gear)

We have maybe 5 Tranzeo left in the system. ‘G’ only… No ‘B’ gear left anywhere.

I’ve seen that spurious -92 on Tranzeo’s connected to XR2’s before. If it works ok and the CCQ is good, leave it for now.

Also, unless you have read up on the power offset and how it works with MT, I wouldn’t change the Tx power. XR2’s die just as easy as an SR2 does when overdriven.

Good luck!

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