When doing mutual redistribution at multiple points (between OSPF and EIGRP on R1 & R2), we may create routing loops so we should use route-map to prevent redistributed routes from redistributing again into the original domain. In the below example, the route-map "SET-TAG" is used to prevent any routes that have been redistributed into EIGRP from redistributed again into OSPF domain by tagging these routes with tag 1: