In TELIPS we have 13 edge routers which makes the IP bearer network for NGN voice traffic. The customer takes a new international link from local service provider and add a default route in KHI-NE80 for all international traffic. But the customer experience one way speech. They can hear the voice of outside pakistan but their voice can not go to international link.
Use command "default-route-advertise" in KHI-NE80 so that it will advertise the default route for international traffic and one way speech problem is solved.
If we import static or direct routes into OSPF then it will not import default routes into OSPF table. We have to use another command "default-route-advertise" to advertised the default route into OSPF of KHI-NE80 and then after OSPF link state synchronisation, all routers will come to know about the default route.
After implementing above command the one way speech problem was solved.