Routing Commands
291
ProSafe Managed Switch
auto-cost (OSPF)
By default, OSPF computes the link cost of each interface from the interface bandwidth.
Faster links have lower metrics, making them more attractive in route selection. The
configuration parameters in the auto-cost reference bandwidth and bandwidth
commands give you control over the default link cost. You can configure for OSPF an
interface bandwidth that is independent of the actual link speed. A second configuration
parameter allows you to control the ratio of interface bandwidth to link cost. The link cost is
computed as the ratio of a reference bandwidth to the interface bandwidth (ref_bw / interface
bandwidth), where interface bandwidth is defined by the bandwidth command. Because the
default reference bandwidth is 100 Mbps, OSPF uses the same default link cost for all
interfaces whose bandwidth is 100 Mbps or greater. Use the auto-cost command to
change the reference bandwidth, specifying the reference bandwidth in megabits per second
(Mbps). The reference bandwidth range is 1-4294967 Mbps. The different reference
bandwidth can be independently configured for OSPFv2 and OSPFv3.
Default
Format auto-cost reference-bandwidth <1 to 4294967>
Mode
no auto-cost reference-bandwidth (OSPF)
Use this command to set the reference bandwidth to the default value.
Format no auto-cost reference-bandwidth
Mode
bandwidth
By default, OSPF computes the link cost of an interface as the ratio of the reference
bandwidth to the interface bandwidth. Reference bandwidth is specified with the auto-cost
command. For the purpose of the OSPF link cost calculation, use the bandwidth command to
specify the interface bandwidth. The bandwidth is specified in kilobits per second. If no
bandwidth is configured, the bandwidth defaults to the actual interface bandwidth for
port-based routing interfaces and to 10 Mbps for VLAN routing interfaces. This command
does not affect the actual speed of an interface.
Default
Format bandwidth <1-10000000>
Mode
100Mbps
Router OSPF Config
Router OSPF Config
actual interface bandwidth
Interface Config