Users Guide

Layer 2 Switching Commands 842
If configuring the switch to MSTP mode, be sure to configure the MST
region name. For multiple switches to become members of the same region,
the configuration name, the configuration revision and mapping of VLANs to
MSTIs must be identical.
In the STP-PV or RSTP-PV modes, BPDUs contain per-VLAN information
instead of the common spanning-tree information (MST/RSTP).
RSTP-PV maintains independent spanning tree information about each
configured VLAN. RSTP-PV uses IEEE 802.1Q trunking and allows a trunked
VLAN to maintain blocked or forwarding state per port on a per VLAN basis.
This allows a trunk port to be forwarding for some VLANs and blocked on
other VLANs.
RSTP-PV extends the IEEE 802.1w standard. It supports faster convergence
than IEEE 802.1D. RSTP-PV is compatible with IEEE 802.1D spanning tree.
RSTP-PV sends BPDUs on all ports instead of only the root bridge sending
BPDUs and supports the discarding, learning, and forwarding states.
When the mode is changed to rapid-pvst, version 0 STP BPDUs are no longer
transmitted and version 2 RSTP-PV BPDUs that carry per-VLAN information
are transmitted on the VLANs enabled for spanning-tree. If a version 0 BPDU
is seen, RSTP-PV reverts to sending version 0 BPDUs.
RSTP-PV embeds support for STP-PV Indirect Link Rapid Convergence and
Direct Link Rapid Convergence. There is no provision to enable or disable
these features in RSTP-PV.
Example
The following example configures the spanning-tree protocol to MSTP.
console(config)#spanning-tree mode mst
spanning-tree mst configuration
Use the spanning-tree mst configuration command in Global Configuration
mode to enable configuring an MST region by entering the multiple
spanning-tree (MST) mode.
Syntax
spanning-tree mst configuration