Hi there,
@jack_george wrote:
I talking about default export policy ... If it exist so no routes will advertise between neighbors
OSPF does not "advertise routes", it generates and floods the LSA. On receiving end, these LSAs are inserted into local LSDB (in addition to self-generated LSAs) and refllooded onwards subject to OSPF flooding scope(s). It is not possible to stop propagating LSAs with export policy, see below.
The OSPF routes are "created" or "built" from LSDB using a litany of checks and algorithms, i.e. SPF is used inside each area and "distance vector" between areas.
Only when all checks pass and algorithms performed, then OSPF routes are inserted into local route table(s).
Export policy works inthe opposite direction - from route table into OSPF LSDB. Hence, You can only use export policy to stop inserting something (apart from direct/inteface routes, see below) from local route table(s) into local OSPF LSDB. It is not possible to stop generating own LSAs for OSPF-enabled-interface routes with export policy since OSPF router LSAs are always generated accroding to RFC 2328.
HTH
Thanks
Alex