High RNC Fails in Nokia RNC + CISCO SGSN network

[Serah]

Dear Experts,
In my RU40 3G network, RNC is Nokia and SGSN is CISCO. In this scenario I am getting high PS RAB setup fails with reason RNC Fails....
When the same RNC is connected to Nokia SGSN, this issue is not there...
Anybody observed this issue? What is the solution?

Thanks in Advance...