User Manual

192
Users Manual of XGS-6350-24X4C
values to interfaces that you want selected first and higher cost values to interfaces that you want selected
last. If all interfaces have the same cost value, spanning tree puts the interface with the lowest interface
number in the forwarding state and blocks the other interfaces.
Beginning in interface configuration mode, follow these steps to configure the cost of an interface:
Command Purpose
spanning-tree rstp costvalue
Configures the cost for an interface.
no spanning-tree rstp cost Returns path cost to default value.
The
modification of the priority of the Ethernet port will arise the recalculation of the
spanning tree. We recommend user to use the default value and let RSTP protocol
calculate the path cost of the current Ethernet interface.
When the port speed is 10Mbps, the path cost of the Ethernet interface is 2000000.
When the port speed is 100Mbps, the path cost of the Ethernet interface is 200000.
19.1.6.7 Configuring the Port Priority
If a loop occurs, spanning tree uses the port priority when selecting an interface to put into the forwarding
state. You can assign higher priority values (lower numerical values) to interfaces that you want selected first,
and lower priority values (higher numerical values) that you want selected last. If all interfaces have the same
priority value, spanning tree puts the interface with the lowest interface number in the forwarding state and
blocks the other interfaces.
Follow these configurations in the interface configuration mode:
Command Purpose
spanning-tree rstp port-priorityvalue
Configures the port priority for an
interface.
no spanning-tree rstp port-priority Returns the port priority to the default
value.
The modification of the priority of the Ethernet interface will arise the recalculation
of the spanning tree.
The default Ethernet interface priority is 128.
Configuring MTSP
19.2
19.2.1 MSTP Overview
19.2.1.1 Introduction
Multiple Spanning Tree Protocol (MSTP) is used to create simple complete topology in the bridging LAN.
MSTP can be compatible with the earlier Spanning Tree Protocol (STP) and Rapid Spanning Tree Protocol
(RSTP).