NetIron, FastIron, ICX, FCX, and other Brocade IP products fail to negotiate/converge STP/RSTP/PVST/RPVST

NetIron, FastIron, ICX, FCX, and other Brocade IP products fail to negotiate/converge STP/RSTP/PVST/RPVST when connected to a VCS/VDX (Ethernet) fabric.