Spanning Tree Configuration
© Copyright Lenovo 2017
Enterprise NOS supports the IEEE 802.1D (2004) Rapid Spanning Tree Protocol
(RSTP), the IEEE 802.1Q (2003) Multiple Spanning Tree Protocol (MSTP), and Per
VLAN Rapid Spanning Tree Protocol (PVRST). The Spanning Tree Protocol (STP)
is used to prevent loops in the network topology.
Up to 256 Spanning Tree Groups can be configured on the switch (STG 256 is
reserved for management). By default, 128 STGs are configured (STG 128 is
reserved for management).
Note: When VRRP is used for active/active redundancy, STG must be enabled.
Table 227.
Spanning Tree Configuration Options
Command Syntax and Usage
spanningtree loopguard
Enables STP loop guard. STP loop guard prevents ports from forwarding
traffic if no BPDUs are received. Ports are placed into a loop‐inconsistent
blocking state until a BPDU is received.
Command mode: Global configuration
spanningtree mode [disable|mst|pvrst|rstp]
Selects and enables Multiple Spanning Tree mode (mst), Per VLAN Rapid
Spanning Tree mode (pvrst) or Rapid Spanning Tree mode (rstp).
The default mode is PVRST.
When you select the disable option, the switch globally turns Spanning Tree
off. All ports are placed into forwarding state. Any BPDU's received are
flooded.
Command mode: Global configuration
[no] spanningtree pvstcompatibility
Enables or disables VLAN tagging of Spanning Tree BPDUs.
The default setting is enabled.
Command mode: Global configuration
[no] spanningtree stgauto
Enables or disables VLAN Automatic STG Assignment (VASA). When
enabled, each time a new VLAN is configured, the switch will automatically
assign the new VLAN its own STG. Conversely, when a VLAN is deleted, if its
STG is not associated with any other VLAN, the STG is returned to the
available pool.
Notes:
When using VASA, a maximum number of 255 automatically assigned
STGs is supported.
VASA applies only to PVRST mode.
Command mode: Global configuration
Chapter 4: Configuration Commands
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