STP question ?

daras

In order to find our DP ports in a LAN segment we 've to calculate the cost to the Root Bridge

The cost is the sum of the link speeds to the Root Bridge,

Lets say the that i 've two switches connected together in Fa0/2 (1st switch) and gi0/1 (2nd) the cost of this link will be 4 or 19

I cant understand this concept

phoeneous

This table sums it up well:

Spanning tree port costs - Packet Life

veritas_libertas

I struggled with this concept for a while as well. The best thing to do is lab it out. Here is a thread on TE discussing this: https://www.techexams.net/forums/ccna-ccent/84636-designated-vs-blocking-port-decision.html

daras

Can you please answer this question to me it is importnat to understand the STP designated ports process

Lets say the that i 've two switches connected together in Fa0/2 (1st switch) and gi0/1 (2nd) the cost of this link will be 4 or 19 ?

Thanks

networker050184

What do you think it will be?

We are here to help, not feed you answers.

JoeBirds

The speed on a link between two switches HAS to be the same or the link will not be in an up/up state. Since they both need to agree on a speed, there can only be one cost to the link. In this case, the link would be a cost of 19 as each switch would autonegotiate to using 100mbps.