OSPF Load Balancing

[Danilo Dy]

OSPF can load balance with two lines, one router at source and one router at destination.

But can OSPF load balance with two lines, one router at source and two routers at destination. The two lines are connected to Router-A at source and Router-B and Router-C at destination. Router-A is in Area 1 and Router-B and Router-C is in Area 2. Connection between Router-A to Router-B and Router-A to Router-C is Area-0.

Any sample?

[thisisshanky · Accepted solution]

Yes, OSPF supports equal cost load balancing. B and C will advertise routes in area 2 to A. If the cost of the links are the same, OSPF will insert both routes into the routing table. Also you can force the cost of the links (even if the links are not equal cost) so that both routes are accepted as equal cost routes by router A.

The route that will be selected for sending a packet will ultimately depend on the switching type (Fast switching, cef, etc) configured on router A.

[Danilo Dy]

Thanks.