the discarding state to the forwarding state. For IEEE 802.1w operation this is the time that a designated port on the bridge spends in the learning state while moving from the disabled state to the forwarding state when both operPointToPointMAC and operEdgePort are false.
/NOTE
Observe the following formulas when setting the previously described parameters:
•Max. Age ≤ 2 x (Forward Delay - 1 second)
•Max. Age ≥ 2 x (Hello Time + 1 second)
Port Priority You can set a port priority from 0 to 240. The lower the number, the greater the probability that the port will be chosen as the root port.
Port Path Cost
You can set a port cost from 1 to 200000000, or specify auto. The lower the number, the greater the probability that the port will be chosen to forward packets. If you specify auto the switch will assign the port cost based on the link speed.
Illustration of STP
A simple illustration of three bridges (or three switches) connected in a loop is depicted in this section. In this example, you can anticipate some major network problems if the STP assistance is not applied. If bridge A broadcasts a packet to bridge B, bridge B will broadcast it to bridge C, and bridge C will broadcast it back to bridge A, and so on. The broadcast packet will be passed indefinitely in a loop, potentially causing a network failure.
STP can be applied as shown in the following illustration. In this example, STP breaks the loop by blocking the connection between bridges B and C. The decision to block a particular connection is based on the STP calculation of the most current bridge and port settings. If bridge A broadcasts a packet to bridge C, bridge C will drop the packet at port 2, and the broadcast will end there.
Setting up an STP using values other than the defaults can be complex. Therefore, keep the default factory settings and the STP will automatically assign root bridges, ports and block loop connections. However, influencing STP to choose a particular bridge as the root bridge using the Priority setting, or influencing STP to choose a particular port to block using the Port Priority and Port Cost settings, is relatively straightforward.
262 | Intel® Blade Server Ethernet Switch Module IXM5414E |
