RSTP Interoperability with Cisco PVST+

Problem:

PowerConnect spanning-tree mode RSTP is not functioning properly with Cisco switches using  spanning-tree mode PVST+.

Solution:

On 802.1Q trunk links connecting PowerConnect switches to Cisco switches VLAN 1 must be added on both sides regardless of the native VLAN configured.

Additional Information:
Cisco switches running PVST+ multicast STP frames on a Cisco STP MC MAC address with the exception of VLAN 1. Only VLAN 1 is sympathetic to the requirements of the IEEE STP MC MAC address.