Cisco recommends to use Virtual-link in case:
- Single transit area crossable by virtual link.
- Area 0 extension over virtual link.
But we still can create virtual-link from area 3 to area 0 through multiple areas.
Configuration Link to heading
hostname R2
router ospf 1
area 1 virtual-link 3.3.3.3
hostname R3
router ospf 1
area 1 virtual-link 2.2.2.2
area 2 virtual-link 4.4.4.4
hostname R4
router ospf 1
area 2 virtual-link 3.3.3.3