STP path cost

SanKuKaï

Hi all,

Can someboby tell me on what is based the calculation of the path cost in stp environment? It is not clearly explained in my books...

Thank a lot for your replies

dtlokee

Path cost is based on the speed of the links back to the root.

Ethernet 100
FastEthernet 19

It is a total of all the interface a frame would exit on the way to root

SanKuKaï

Speed of the links?

The connected ports bandwidth then...??

dtlokee

Yes, so if you had 2 FastEthernet segments and one Ethernet segment between a switch and the root the cost would be 138

SanKuKaï

Thank you!

Helped a lot!

totts

Path costs are:
10Mbps = 100
100Mbps = 19
1Gbps = 4
10Gbps = 2