Roamer Ping Pong location update

Dear All:
I had a problem I think maybe I can share it with you.
We have some roamers in our network that they are doing ping pong location update so in each few seconds this roamer is doing location update.

First of all I check the BSS part there was a big value for ping pong handicap it was around 20 Db so it can not because of that and we can not say all of these roamers are just going and coming back each second in the same area it should be another problem.

I am afraid if there be a problem in the authentication or …becuse the location update and cancel location update is complete and after that location is canceled because of authentication issue or …and after its do location update from another MSC.

i will be happy if you send me email: s_mousavie@yahoo.com