Nortel-2G BSS connected to Nortel NSS.
Ericsson-2G BSS connected to Ericsson NSS.
Ericsson-RNC connected to Ericsson NSS.
If I use any MS (except K660i) 2g->3G & 3G –>2G in any zone(Zone-A/B/C) no problem.
If I use K660i 2g–>3g(ericsson 2g area–>ericsson 3g area) —->problem occurs.
but ericsson 3g area–>ericsson 2g area no problem.
if I use K660i Nortel 2g to Ericsson 3g no problem & Ericsson 3g —>Nortel 2g no problem.
in any other circle except my circle, ericsson 2g area to ericsson 3g & vice versa has been tested successfully.
Hope,now I have made the scenario clear.
If need any input more pls ask