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Hi everyone, I have a shocking case to propose you:
Our customer have a wireless infrastructure composed by about 8 access point Symbol AP-4121 (802.11b), and about 10 Symbol PDT6846 and many Psion, Datalogic RF terminal.
We have sold 3 Motorola MC9090-G with extremely security but the result was unexpected.
Only the MC9090s work very bad with a lot of disconnection during the Telnet session (5250 emulation), the ping from PC fall down suddenly even though the AP is from about 7-8 meters far and return to reply if I start a ping from STA.
There aren't IP conflict and nothing interference (other STA works properly).
All the 3 MC9090s lose the connection in different places and in different times.
AP-4121 haven't power save mode activable but MC are in Fast Power save mode, Do you think that is a PSP mistake?
In AP4121, the short RF preamble is enable but this features on these old AP is not yet reliable.
In the next days I will try to do some test but, now, I haven't any idea about this never seen problem.

Thank you for the attention and availablity.

Nicol???????2 8)

First I would say to go long preamble on the AP's. It doesn't cost any throughput when dealing with low data devices such as your terminals. This probably won't solve anything but is would be prudent to set it.

Next, do you have a way of performing a packet capture? With problems such as these, it is essential to be able to see what is happening at the protocol level.

GT

Hello Nicolo,
I would ensure that the MC9090's are running the latest OS (BSP) and Fusion Hot fix from http://support.symbol.com. Also, ensure that the Wavelink Client is the latest and greatest available from the Wavelink download site.

There are no issues with Fast Power Save mode and Short Preamble with the AP4121. The AP4121 should be running firmware v2.70-12 or -13 (last available release).

If issues are still persistent, as GT stated, a protocol analyzer capture would be required. You can also obtain Netlog (capture software that sits on the MC9090) from Microsoft and/or Motorola Support (800.653.5350).

Thnak you at all for the fast answers. :)
Sure, the long preamble setup on the APs is one of my next action.
MC9090's firmware is the latest and the TelnetCE's firmware is the latest too.
I think that upgrade the AP4121 firmware at the last relase should be a good idea but i must study the correct procedure to do it because I have never try...have you got any white papers about?

Yes, I have a Omnipeek ready to start capture and I will use it in my office test.

Now I am curious to try your advices...
Thank you very much guys! ;-)

See you (very) soon!

Hi Nicolo,

Hopefully my post would save you alot of time as I have invested with exactly the same issues you're having.

Scenario: small automotive warehouse 3 AP's 2x Ap4121 + 1x Ap4131

Rf guns 10x PDT6846

we issued 10 MC9090G WM5 devices running Wavelink TelnetCe connecting to AS400 5250 emulation.

AP's upgraded to latest firmware:
Wavelink Upgraded to latest firmware:
MC9090's running latest fusion build:

Wireless coverage excellent:
Channel Allocation OK: No RF interfereance detected:

Problem: 10 MC9090G drops outs random. PDT6846 no reported issue or not as much.

Pings to MC9090's drops out randomly. It will suddenly come back.

Connection to AS400 gets dumped to X-Wait all the time.

Solution:
Optional: Power settings to MC9090 set to CAM not PSP. " Big Ping replies latency diffrence"
Optional: Set IP address to static. "Notice DHCP server too slow"

The main problem is the AP's. I was fortunate to work on a small warehouse where I was able to introduce a spare AP5131 and temporarily erected.

I allocated the use of MC9090 to a confined area and power down one of the AP4121 and activate the AP5131 in its place.

Problem disappeared: The site has been happily working for over 12months now and we have since erected AP5131's inplace of AP4121's.

This problem gave me alot of headache as it is very intermittent.

No firmware upgrades on all hardware fixed the issue.

I hope this helps you.

Thank you KheenTech!!
This is perfectly the identical problem I have!
Only 2 dubts:

(!) MC9090 CAM mode shocking decrease the battery duration...and this thing should be a disadvantage regard Psion, Denso and other vendor's RF terminals.
(!) IP addresses in the WLAN are all static assigned so, I exclude any Dhcp issue.

Now I'm testing the situation in my office and, as feared, everything is working properly. :x

I hope to find another solution...

Thank you for the share! ;-)

After the tests...these are the results:

AP4121:Latest firmware
MC9090:Latest build

AP4111/21 doesn't have power save management so RF terminals cannot work with power safe mode enabled.
If PS is enabled on STA and you move out Rf's coverage than come back in. ping request will be timed out even though it is in associated state and ping doesn't reply nevermore.
Ping turn up only if you start a ping request from STA to PC.
In CAM mode everything works properly but I have any fear about battery duration.

Do you have any other advice?

Thank you all! 8)

Hi Nicolo

Don't know if you done this or not, but have you contacted any of the manufacturers of the equipment items to see what they have to say ?

Many have databases of known problems/issues with other manufacturer's gear. They don't usually give out this information unless you say something like "We have some of your products as well as those from company x and company y....we're thinking of going with someone else for future orders due to the problems that we are having with YOUR equipment".

I'd make this call to a sales person first rather than tech support. Most tech support people are "contracted out" these days, and many couldn't care less if you don't buy from them again.

But if you make a call to a sales person, that can be very different. They will usually go to the tech folks and put pressure on them.

I've used this loads of times in the past where I've done a stack of tests and had a good feeling that the problems I was encountering had to do with configuration/firmware issues that were not advertised. Lo and behold a few days later I'd get a document mailed to me that said something like "Known compatibility issues of the XXXXX modem interworking with the YYYYYY modem"

Good satellite network operators like Intelsat have open standards so that [ in theory ] any Intelsat approved [ Intelsat Earth Station Standards IESS, like IEEE ] piece of equipment should work with any other from a different manufacturer.

Give it a try, it may work....

Have also done this with Cisco WLAN gear and some client adaptors from another manufacturer.

Dave

Hello Nicolo,
The AP4121 does indeed support PSP with Motorola MU's. There is no setting for this on the AP, it's part of the firmware algorithm. CAM mode is always going to have better results.

I would be interested in knowing what OS and Fusion builds you currently have running on the MC9090. The AP4111/AP4121 have long been end-of-life (EOL) and are considered first generation 802.11b access points (over 10 years old) from Motorola (formally Symbol). The AP4131 followed after and is also EOL.

The AP5131 (802.11bga) and AP7131 (802.11abgn), as well as wireless controllers using either thin access ports (AP300abg/AP650abgn) or adaptive AP's (5131/7131) are the latest and greatest from Motorola.

I would probably take a wireless capture and see what is actually going on and due to the technology being EOL, I would really look into purchasing newer AP's, though I know of many sites that are still running on the AP4131's and using the MC9090 devices with no issues.

Hi Nicolo,

Here is my suggestion.

If you're saying that the issue you have is regarding PSP/CAM mode but fear you will have to sacrifice battery life, to maintain reliable RF connectivity. I suggest you start looking at a midleware software.

I am refering to Wavelinks Term Proxy. The TermProxy Server allows you to avoid dropped connections and automatically reconnect by acting as an intermediary connection server between the client device and the host application server.

You can obtain more info @ www.wavelink.com

I hope this helps
Kheen