(TRP) parameter in NSN

Dear Experts;
the TRP parameter mean the TRX priority in TCH Allocation.

my quastion:-
what is the peter?..
1- value 0, no priority.
2- value 1,traffic channel is allocated primarily from the BCCH Trx.
3- value 2, traffic channel allocated primarily from another Trx than the BCCH Trx.

please i waiting your feedback based on your experince & test.

Best Regards
Atheer