Task 3.5 BGP Reachability
in this task, do we really have to do the redistribution on R3? Let's not forget that R3 is originating a default route into the OSPF domain hence R5 is using that default route. R5 can still reach AS254 routes and even Vlan 3 without any redistribution being performed on R3.
NB: For the IGP loop prevention, I have change the OSPF external distance to 171 on R3 and SW2 instead of using route tagging.