AT&T proposes a three step approach to evolving 5G architecture from early deployment to more mature phases:
1) Early 5G deployment using Phase 1 Option 3 architecture.
2) Phase 1 evolution to Option 7 architecture while still supporting Option 3, through software upgrades.
3) Phase 2 evolution to Option 2/4 architecture while still supporting Options 3 and 7, with specifications that allow different architectures to coexist.