fast roaming

[pam]

i am wondering if there is an ap setting that i am missing. i have configured mobility groups with the wlsm, i have all of the aps authenticating and for my initial tests i have hard coded ip addreses. i have done the walkabout surveys with the wlse and applied the output to the radios. however, when i walk aroung doing a continuous ping, i will come to a spot where the ping traffic drops and loses the signal. the problem is i may be standing underneath another access point. if i wait, th client will associate with the nearest ap. i think it should transition more smoothly. i am using both 2000 and xp and i am testing with the cisco abg cards.

what am i missing?

any ideas

thanks

paul

[kwonza]

I have been working this issue also over the past month. We've seen this type of roaming issue with both the 802.11b and abg Cisco cards. At times, we've seen better roaming features with an Intel b/g internal card on IBM ThinkPad laptops. I've spoken with Cisco (both TAC and SE) on this issue and noone seems to have a definitive answer. We noticed the cards tend to hang on, even when the db is considerably weak (i.e. -85/90) Then when we restart the card near another AP....-50dbm...incredible. We are designing our WLAN for Vocera, so we are creating smaller cells for roaming. Will continue to work it.....

[pam]

it so happens i am doing the same type of implementation at a hospital/health system also. we are in the process of doing soemthing similar in that if the data pcs and roaming work correctly, we will be rolling out vocera throughout our new facility.

i had a couple of thoughts regarding the wlse radio scan. since we are 5 stories and some of the aps bleed through. i was wondering how you set your radios up. did you use maximum power or did you scale it back in the hope that the cards would let go of a particular ap sooner and switch to a closer/stronger signal? i also noticed that the latest drivers for the integrated intel cards (gateway pcs) seem to help

anyway i would like to keep up with your implementation

thanks

paul

[dixho]

The roaming function is largely determined by the wireless client. The sequence of events for a wireless client to roam are as follows:

1. the wireless client stops transmitting and receiving. Scan all channels and look for beacons from APs

2. Based on the signal strength and signal quality, the wireless client makes a decision on whether stay at the current AP or roam to a new AP.

ACU (i.e. 350 wireless clients) allows you to configure how long the wireless has to stay at the current AP and minimum signal strength for roaming. Both parameters prevent 350 wireless clients from roaming too frequently.

ADU 1.2.0.4 (i.e. CB21AG) only allows you to configure how long the wireless has to stay at the current AP.

I think that you are on the right track. You need to find out the roaming logic of wireless clients. Upgrading the latest wireless driver may help.

[dixho]

If you use Cisco CB21AG card, please upgrade to ADU 1.2.0.4. There are some roaming issues on CB21AG before ADU 1.2.0.4. (i.e. CSCef00136)

[d.beaver]

Do you have any of your AP's set to 100mW's? I was just curious as to the power settings on each of your access points. I have run into the same issues in several locations, not taking into account that the clients power levels need to be adjusted to the level of the highest powered access point. So if you have 10 AP's and the highest power of any of those is 50mW, you need to adjust each client to 50mW to prevent the client from hanging on too long.

You may have already done this, just a thought.

Dave

[crose]

I have the exact same issue with the exact same cards. It causing us no end of headache as the roaming does not work properly or smoothly. I hate to rag on cisco but these abg cards are pretty bad. They have been nothing but problems and driver upgrades for the last year it seems.