Brocade Network OS Command Reference v4.1.0 - Manual (Page 84)

46 Network OS Command Reference
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auto-cost reference-bandwidth (OSPF)
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auto-cost reference-bandwidth (OSPF)
Configures reference bandwidth.
Synopsis auto-cost reference-bandwidth {ref-bw | use-active-ports}
no auto-cost reference-bandwidth
Operands ref-bw Reference bandwidth in Mbps. Valid values range from 1
through 4294967.
use-active-ports When set, any dynamic change in bandwidth immediately affects the cost
of OSPF routes. This parameter enables cost calculation for currently active
ports only.
Defaults Reference bandwidth is 100 Mbps.
Command Modes OSPF VRF router configuration mode
Description Use this command to configure the reference bandwidth. OSPF calculates the cost of a route as
the ratio of the reference bandwidth to the bandwidth of the egress interface. An increase in the
reference bandwidth results in an increased cost. If the resulting cost is less than 1, the software
rounds the cost up to 1.
Usage Guidelines The bandwidth for interfaces that consist of more than one physical port is calculated as follows:
• LAG group — The combined bandwidth of all the ports.
• Virtual interface — The combined bandwidth of all the ports in the port-based VLAN that
contains the virtual interface.
If a change to the reference bandwidth results in a cost change to an interface, the device sends a
link-state update to update the costs of interfaces advertised by the device.
NOTE
If you specify the cost for an individual interface (by using the ip ospf cost command), the cost you
specify overrides the cost calculated by the software.
Enter no auto-cost reference-bandwidth to disable bandwidth configuration.
Examples To change a reference bandwidth of 500:
switch# configure
switch(config)# rbridge-id 5
switch(config-rbridge-id-5)#router ospf
switch(config-router-ospf-vrf-default-vrf)# auto-cost reference-bandwidth 500
The reference bandwidth specified in this example results in the following costs:
• 10 Mbps port’s cost = 500/10 = 50.
• 100 Mbps port’s cost = 500/100 = 5.
• 1000 Mbps port’s cost = 500/1000 = 0.5, which is rounded up to 1.
The costs for 10 Mbps and 100 Mbps ports change as a result of the changed reference
bandwidth. Costs for higher-speed interfaces remain the same.
See Also ip ospf cost