I have some basic knowledge about the split:
Various, CU (Central Unit) and DU(Distributed Unit) split options are discussed in 38.801 Section 11.1.1.
I think the option 2 is agreed for HLS (High layer split).
Basically split helps the operator with the following
- Helps in multivendor interoperability (like CU can be from one vendor and DU from another)
- Help in Implement virtualisation of CU