Cisco HWIC-4ESW - Page 39

Cisco HWIC-4ESW and HWIC-D-9ESW EtherSwitch Interface Cards
How to Configure EtherSwitch HWICs
39
Book Title
Calculating Port Cost
Port cost value calculations are based on the bandwidth of the port. There are two classes of values. Short
(16-bit) values are specified by the IEEE 802.1D specification and range in value from 1 to 65535. Long
(32-bit) values are specified by the IEEE 802.1t specification and range in value from 1 to 200,000,000.
Assigning Short Port Cost Values
You can manually assign port costs in the range of 1 to 65535. Default cost values are as follows.
Assigning Long Port Cost Values
You can manually assign port costs in the range of 1 to 200,000,000. Recommended cost values are as
follows.
Follow the steps below to configure the spanning tree port cost of an interface.
SUMMARY STEPS
1. enable
2. configure terminal
3. interface {ethernet | fastethernet} interface-id
4. spanning-tree cost port-cost
5. spanning-tree vlan vlan-ID cost port-cost
6. end
7. show spanning-tree interface
Port Speed Default Cost Value
10 Mbps 100
100 Mbps 19
Port Speed Recommended Value Recommended Range
10 Mbps 2,000,000 200,000 to 20,000,000
100 Mbps 200,000 20,000 to 2,000,000