Motorola MC9090 handhelds and 7363 Access Points with Zone Director

[michael_daracz]

I have 4 motorola handheld guns roaming between 6 overlapping 7363 access points with Zone Director 1100. The guns are running a simple wavelink telnet application. They are sitting on a separate open WLAN with no authenticaion but with an MAC ACL. Intermittently, the guns are having problems re-establishing a link to the access point(bars that indicate signal strength go from full to none, and the handheld indicates that it lost connection with the server), even though they are within the range of them. It doesn't happen often but its annoying enough. It usually takes 10 - 20 seconds to re establish a link. What settings should I check? Thank you!

I

[sid_sok]

I ran into an interesting case that I just closed last week. It was also a Motorola handheld scanner and the initial problem with general disconnection, RF issue, roaming and telnet disconnects. We ran through the usual data gathering and found out the APs channel were changing, the clients were not roaming well and were leaving the old AP when the old AP can barely hear the client and so on. We even saw a "loop detected, host only mode" message and so on. To address issues as we found we did the following:

1. Statically assign the channel, mapped out for best coverage/channel spacing.
2. Set BSS min rate to 12 -> client roamed before it got out of range
3. upgrade to 9.6.2.0.13 -> No more loop detect issue

Even after that there were still a few telnet disconnects, a lot less then before but still a few every now and then. Further troubleshooting and some coordinated packet capture seems to pin point the problem with the Telnet disconnects were occurring right about the time we saw lots of ARP packet being sent directly to the handheld. The ARP were for something completely different, but it was a unicast to the handheld.

It turned out that this environment did not have many clients so the Multicast to unicast conversion was being done. I am not 100% sure why this helped, but it did, after disabling directed multicast, the handheld no longer dropped telnet. It might be the various APR packet were filing up it's ARP table entry or something but disabling Multicast to unicast conversion resolved the final issue. If you want to give it a try here is the commmand:

ruckus# config
You have all rights in this mode.
ruckus(config)# wlan HANDHELD
The WLAN service 'HANDHELD' has been loaded. To save the WLAN service, type 'end' or 'exit'.
ruckus(config-wlan)# no qos directed-multicast
The command was executed successfully. To save the changes, type 'end' or 'exit'.
ruckus(config-wlan)# end
The WLAN service 'HANDHELD' has been updated and saved.
Your changes have been saved.
ruckus(config)# end
Your changes have been saved.
ruckus#

Again this was only done once we eliminated the RF issue, the roaming issue and the Loop detected issue with an upgrade. A good coordinated packet capture would help clarify the issue.

Sid