– If you are going to use two LACs for one city, at the borders of each LAC, make sure that the cells at the LAC borders dont share the same traffic area (in order to avoid to much paging load between them).
– The number of TRX for one LAC depends on the BSC or in BSC-s that you are going to use.
Sorry for my mistake: instead of location update load I have written paging load.
So, for my opinion defining 2 LACS for one city, is important to avoid location update load, between border cells, as much as possible.
LACS borders is better to be choosen between cells that aren’t very good adjacent cells with each other (based on traffic sharing), so in this case we avoid to much location update between them.