Advanced Traffic Management Guide K/KA/KB.15.15

Single spanning tree applications One spanning tree variant can be run on the switch at any
given time. On a switch running RPVST+, MSTP cannot be
enabled. However, any MSTP-specific configuration settings
in the startup configuration file will be maintained.
Exclusions
The following features cannot run concurrently with RPVST+:
• Features that dynamically assign ports to VLANs:
GVRP◦
◦ RADIUS-based VLAN assignments (802.1X, WebAuth, MKAC auth
◦ Auth-VID/UnAuth-VID configuration on interfaces
◦ MAC-Based VLANs
◦ LLDP Radio Port VLAN
• Switch Meshing
• QinQ
• Protocol VLANs
• Distributed Trunking
• Filter Multicast in rapid-PVST mode (The multicast MAC address value cannot
be set to the PVST MAC address 01:00:0c:cc:cc:cd.)
GVRP Spanning tree mode cannot be set to RPVST+ when GVRP is enabled, and GVRP cannot
be enabled when RPVST+ is enabled.
RPVST+ operating limits Virtual ports (vPorts) on a switch are determined by the
number of physical ports on the switch, plus other factors.
Exceeding the recommended number of vPorts can result in
dropped BPDUs.
Allowing traffic on per-VLAN ID
(PVID) mismatched links
The switch generates an Event Log message for a VID
mismatch on an active RPVST+ VLAN only if
ignore-pvid-inconsistency is disabled (the default).
If ignore-pvid-inconsistency is enabled on multiple
switches connected by hubs, there could be more than two
VLANs involved in PVID mismatches that will be ignored by
RPVST+.
If there is an actual misconfiguration of port VLAN
memberships in a network, then enabling
ignore-pvid-inconsistency prevents RPVST+ from detecting
the problem. This could result in packet duplication in the
network because RPVST+ would not converge correctly.
About RPVST+ 167