Core Issue
Route Redistribution is used to propagate routes learned using one protocol, into another routing protocol. When BGP is redistributed into an IGP, only eBGP learned routes get redistributed. The iBGP learned routes known on the router are not introduced into the IGP in order to prevent routing loops from being formed.
Resolution
By default, iBGP redistribution into IGP is disabled. To enable redistribution of iBGP routes into IGP, issue the bgp redistribute-internal command. Precautions should be taken to redistribute specific routes using route maps into IGP.
A sample configuration for redistributing iBGP routes into OSPF is shown below.
router bgp 65345
[...]
bgp redistribute-internal
!
router ospf 100
[...]
redistribute bgp 65345 subnets
Note: Redistributing internal Border Gateway Protocol (iBGP) routes into an Interior Gateway Protocol may cause routing loops within the Autonomous System (AS). This is not recommended. Route filters should be set to control the information which is imported into the IGP.
For more information Border Gateway Protocol (BGP)
