Redistribution Notes

  • Redistribution is ONLY for routes in the routing table.
  • Redistribution is NOT transitive on the same router. If redistributing from RIP into OSPF and OSPF into ISIS, you will need to also redistribute from RIP into ISIS.
  • A redistributed route from 1 protocol, will not be redistributed into another protocol on the same router.
  • if you are using route-maps when redistributing to classful protocols [RIP], make sure that the ACL is for a classful network.
  • When redistribution from OSPF/EIGRP into RIP, summarize to the mask of the RIP interface.
  • Always include a metric either as default-metric or on the redistribution statement. The router does not know how to translate from one metric to the other.
  • SINGLE POINT OF MUTUAL REDISTRIBUTION: NO NEED FOR ROUTE-MAPS/DISTRIBUTION-LISTS.

Route maps

  • Before redistribution, on the redistributing router, issue a command "show ip route" and write the learned routes.
  • Make an ACL that permits those routes in 1 including the connected subnets that the routing protocol is running between routers.
  • Make 2 route maps:
    1. One that would deny matching the ACL in 2 and the other that would permit anything (this will be used on non-tag capable IGPs).
    2. With only one entry that would permit all the routes matching ACL in 2.
  • Do the necessary redistribution using the route-maps just made or use the distance command at redistribution point