When Spanning Tree is converging no data is being sent?

[vazurahan]

No data will be forwarded until convergence is complete. says on page 521

Is this between host on different switches connected by a cable? Or is this between host on the same switch?

For example, I have a Switch A and Switch B which are connected together by a crossover cable. I have 2 hosts connected to switch A with portFast enabled. Suddenly there was another switch or cable connected between switch A and B causing STP to try to converge. Does this mean that the two host on Switch A won't be able to talk to each other while the STP is trying to converge? How about if portFast is disabled?

[Fuzz]

With 802.1D spanning tree, all switches in the topology will block all ports during convergence while the recalculation of root ports is happening. This is the only way to prevent a loop. This can be 50 seconds while the ports transition through the states. PortFast reduces this time as it makes the port skip listening and learning states, but the port will still go down for a short period during convergence.