In a switched network where part of the switches are configured with Rapid PVST+ and part are with PVST+ (migration from STP to RSTP case),
when a network failure occurs, I assume that part of the network converve slowly because of use of STP and the other part converges quickly because of the use of RSTP.
How do you explain that there is never a loop in the network while part of the network ports change its state more quickly than other ?
I have understood that with STP and MSTP interoperability, this issue is resolved by the concept of virtual bridge (STP sees MST region as a single switch). But if we use RSTP there is no such thing as virtual bridge.
A possible response is that with STP/RSTP, the switches configured with RTSP force a slow convergence in the same way as STP in case STP BPDU is seen on the network ?