Setting The Spanning Tree Mode - H3C S6850 Series Configuration Manual

Configuring the BPDU transmission rate
Configuring edge ports
Configuring path costs of ports
Configuring the port priority
Configuring the port link type
(Optional.)
5.
(Optional.)
6.
Enabling the spanning tree feature
7.
(Optional.) Configuring advanced spanning tree features
8.
Performing mCheck
Configuring Digest Snooping
Configuring No Agreement Check
Configuring TC Snooping
Configuring protection features
Disabling the device from reactivating edge ports shut down by BPDU guard
Enabling BPDU transparent transmission on a port
Enabling SNMP notifications for new-root election and topology change events

Setting the spanning tree mode

About spanning tree mode
The spanning tree modes include:
•
STP mode—All ports of the device send STP BPDUs. Select this mode when the peer device
of a port supports only STP.
•
RSTP mode—All ports of the device send RSTP BPDUs. A port in this mode automatically
transits to the STP mode when it receives STP BPDUs from the peer device. A port in this mode
does not transit to the MSTP mode when it receives MSTP BPDUs from the peer device.
•
PVST mode—All ports of the device send PVST BPDUs. Each VLAN maintains a spanning
tree. In a network, the amount of spanning trees maintained by all devices equals the number of
PVST-enabled VLANs multiplied by the number of PVST-enabled ports. If the amount of
spanning trees exceeds the capacity of the network, device CPUs will be overloaded. Packet
forwarding is interrupted, and the network becomes unstable. The device can maintain
spanning trees for 500 VLANs.
•
MSTP mode—All ports of the device send MSTP BPDUs. A port in this mode automatically
transits to the STP mode when receiving STP BPDUs from the peer device. A port in this mode
does not transit to the RSTP mode when receiving RSTP BPDUs from the peer device.
Restrictions and guidelines
The MSTP mode is compatible with the RSTP mode, and the RSTP mode is compatible with the STP
mode.
Compatibility of the PVST mode depends on the link type of a port.
•
On an access port, the PVST mode is compatible with other spanning tree modes in all VLANs.
•
On a trunk port or hybrid port, the PVST mode is compatible with other spanning tree modes
only in the default VLAN.
Procedure
Enter system view.
1.
system-view
Configuring the mode a port uses to recognize and send MSTP frames
Enabling outputting port state transition information
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