Dell Force10 E600i FTOS Version 8.4.1.5 Configuration Guide for ExaScale - Page 665

OSPF Cost OSPF calculates the shortest path to a destination by taking into account the cost of the available OSPF links. In OSPF, a lower link cost indicates a preferred interface to use for sending traffic. An OSPF cost is a value that ranges from 1 to 65535. By default link costs are automatically calculated on an OSPF router according to the bandwidth provided by each interface type; for example, the default cost on a 10GE or 100MB interface is 1 and on a 10MB interface is 10. The default OSPF cost on an interface is calculated as: 108 / interface bandwidth (in bps). The higher the cost, the less likely for an interface to be used to transmit OSPF traffic. You can specify that the cost for transmitting OSPF packets on an interface is calculated according to an amount of specified bandwidth globally configured with the auto-cost reference-bandwidth command. In this case, the OSPF cost is calculated as: reference-bandwidth / interface bandwidth (in bps). The higher the reference bandwidth, the higher the cost. You can also explicitly configure the cost for transmitting OSPF packets on an interface by using the ip ospf cost command in interface configuration mode and specifying a cost value from 1 to 65535. The configuration commands used to configure OSPF cost are as follows: Command Syntax auto-cost reference-bandwidth ip ospf cost Command Mode ROUTER OSPF CONFIG-INTERFACE Usage Configure the cost of transmitting OSPF traffic on router interfaces to be calculated according to the specified reference bandwidth. Range: 1 to 4294967 (megabits per second). Default: 100 MB per second. Change the cost associated with transmitting OSPF traffic on an interface. Range: 1 to 65535. The default cost depends on the interface speed. Implementing OSPF with FTOS FTOS supports up to 10,000 OSPF routes. Within that 10,000 up to 8,000 routes can be designated as external and up to 2,000 designated as inter/intra area routes. FTOS version 7.8.1.0 and later support multiple OSPF processes (OSPF MP). Prior to 7.8.1.0, FTOS supports 1 OSPFv2 and 1 OSPFv3 process ID per system. Recall that OSPFv2 and OSPFv3 can coexist but must be configured individually. Open Shortest Path First (OSPFv2 and OSPFv3) | 665