FAQ-Why Cannot Interfaces of Different Types Generate Equal-Cost Routes and Establish OSPF Load Balancing

Publication Date:  2015-05-05 Views:  84 Downloads:  0
Issue Description
Why Cannot Interfaces of Different Types Generate Equal-Cost Routes and Establish OSPF Load Balancing?
Solution
OSPF can automatically calculate the cost of an interface based on the interface bandwidth. The calculation formula is: Interface cost = Bandwidth reference value/Interface bandwidth. The bandwidth reference value is configurable. The default value is 100 Mbit/s. Routes generated by OSPF have the same priority (10 by default). The interface cost, however, depends on the interface type. Interfaces of different types have different costs; therefore, the interfaces cannot generate equal-cost routes, leading to failure in establishing load balancing.

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