Sequence while sorting an internal table

Hi Experts,

My problem while sorting an internal table is the sequence of record.

I have an internal table with content as :

             Area  No.                       Name

                     11                       AAA

                     12                       BBB

                     09                       PPP

                     04                       QQQ

                     11                       LLL

                     58                       OOO

                     89                       TTT

                     11                       MM

Now I am using the SORT as :

               SORT itab by area_no.

My query is that...Is it always like that record of area no 11 with name AAA will come before name LLL and then MM.

I need the clarification if the area no are same then is it for sure that the sequence of name would always be maintained,

and SAP uses which algorithm to sort tables?