NEC N8406-022 manual spanning-treemstp, <1-32characters>

Rapid Spanning Tree Protocol / Multiple Spanning Tree Protocol configuration

The switch supports the IEEE 802.1w Rapid Spanning Tree Protocol (RSTP) and IEEE 802.1s Multiple Spanning Tree Protocol (MSTP). MSTP allows you to map many VLANs to a small number of spanning tree groups, each with its own topology.

You can configure up to 31 spanning tree groups on the switch (STG 32 is reserved for switch management). MRST is turned off by default.

NOTE: When Multiple Spanning Tree is turned on, VLAN 1 is moved from Spanning Tree Group 1 to the Common Internal Spanning Tree (CIST). When Multiple Spanning Tree is turned off, VLAN 1 is moved back to Spanning Tree Group 1.

The following table describes the Multiple Spanning Tree Configuration commands.

Table 79 Multiple Spanning Tree Configuration commands

Command		Description
[no]	spanning-tree mstp	Configures a name for the MSTP region. All devices within a MSTP region
name	{<1-32 characters>}	must have the same region name.

Command mode: Global configuration

spanning-tree mstp version {<0-65535>}

Configures the revision level for the MSTP region. The revision level is used as a numerical identifier for the region. All devices within a MSTP region must have the same revision level number. The range is 0-65535.

Command mode: Global configuration

spanning-tree mstp		Configures the maximum number of bridge hops a packet may to traverse
maximum-hop <4-60>		before it is dropped. The range is from 4 to 60 hops. The default is 20.
		Command mode: Global configuration
spanning-tree mrst	mode	Selects either Rapid Spanning Tree mode (rstp) or Multiple Spanning Tree
{mstrstp}		mode (mstp). The default mode is RSTP.
		Command mode: Global configuration
spanning-tree mrst	enable	Globally turn RSTP/MSTP ON.
		Note: When RSTP is turned on, the configuration parameters for STP group 1
		apply to RSTP.
		Command mode: Global configuration
no spanning-tree mrst		Globally turn RSTP/MSTP OFF.
enable		Command mode: Global configuration
show spanning-tree	mrst	Displays the current RSTP/MSTP configuration.
		Command mode: All

NOTE:

•IEEE 802.1w standard-based RSTP implementation runs on one STG (i.e. same as one spanning tree instance) only. As a result, if ‘rstp’ mode is selected, then only a single RSTP instance (default for STG 1) is supported for all VLANs, including the Default VLAN 1.

•If multiple spanning tree instances are required, then select ‘mstp’ mode so that multiple VLANs are handled by multiple spanning tree instances, as specified by IEEE 802.1s standard-based MSTP implementation.

•IEEE 802.1s MSTP supports rapid convergence using IEEE 802.1w RSTP.

•PVST+ does not support rapid convergence in current versions.

NOTE:

The following configurations are unsupported:

•PVST+ (default Spanning Tree setting) is NOT interoperable with Cisco Rapid PVST+.

•MSTP/RSTP (with mode set to either ‘mstp’ or ‘rstp’) is NOT interoperable with Cisco Rapid PVST+.

The following configurations are supported:

•PVST+ (default Spanning Tree setting) is interoperable with Cisco PVST+.

•MSTP/RSTP (with mode set to ‘mstp’) is interoperable with Cisco MST/RSTP.

Configuration Commands 75