RSTP and MSTP

Port type and link type

Spanning Tree Configuration includes the following parameters to support RSTP and MSTP:

Edge port

Link type

Although these parameters are configured for Spanning Tree Groups 1-128 (/cfg/l2/stp y/port x), they only take effect when RSTP/MSTP is turned on.

Edge port

A port that connects to a server or stub network is called an edge port. Therefore, ports 1-16 should have edge enabled. Edge ports can start forwarding as soon as the link is up.

Edge ports do not take part in Spanning Tree, and should not receive BPDUs. If a port with edge enabled does receive a BPDU, it begins STP processing until it is re-enabled.

Link type

The link type determines how the port behaves in regard to Rapid Spanning Tree. The link type corresponds to the duplex mode of the port. A full-duplex link is point-to-point (p2p), while a half-duplex link should be configured as shared. If you select auto as the link type, the port dynamically configures the link type.

RSTP configuration guidelines

This section provides important information about configuring Rapid Spanning Tree Groups:

When RSTP is turned on, STP parameters apply only to STP Group 1.

When RSTP is turned on, all VLANs from STP Groups other than STP Group 1 are moved to STP Group 1. The other STP Groups (2-128) are turned off.

RSTP configuration example

This section provides steps to configure Rapid Spanning Tree on the switch, using the Command Line Interface (CLI) or the Browser-based Interface (BBI).

Configuring Rapid Spanning Tree (CLI example)

1.Configure port and VLAN membership on the switch, as described in the “Configuring ports and VLANs (CLI example)” section in the “VLANs” chapter of this guide.

2.Set the Spanning Tree mode to Rapid Spanning Tree.

>> /cfg/l2/mrst

(Select Multiple Spanning Tree menu)

>> Multiple Spanning Tree# mode rstp

(Set mode to Rapid Spanning Tree)

>> Multiple Spanning Tree# on

(Turn Rapid Spanning Tree on)

3. Apply and save the changes.

>>

#

apply

(Apply the configuration)

>>

#

save

(Save the configuration)

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