Redistribution | Layer 3 Switching

Mutual Redistribution of RIP and OSPF

My IE-R&S Hunt, Redistribution No Responses »

Jun 052013

R4 advertises loopback 0 into RIP, which is further redistributed by R2 into OSPF. R3 then redistributes OSPF back to RIP with a metric of 1 which causes 2 problems.

First problem is that R2 has 2 paths to reach the loopback of R4 one from R4 itself and other being redistributed by R3. Second problem is that link between R1 and R2 will not be advertised to R4 because of the distance vector problem (a router will only advertise a route if it has the protocol activated on the link or if it learns the route from a remote source via the same routing protocol).

Redistribution of EIGRP External routes to OSPF

My IE-R&S Hunt, Redistribution No Responses »

May 312013

R4 redistributes loopback 0 in EIGRP, which is further redistributed by R2 into OSPF. R3 then redistributes OSPF back to EIGRP. This causes R2 to have 2 paths to reach the loopback of R4 and this may cause routing loops

When there are multiple points of redistribution, and the network which is being redistributed could only be reached via one path, then the initial router which is redistributing must not choose any other path other than the one from which it initially learned.