PLANET XGS3-24040 - Manual (Page 143)

Chapter 16 MSTP Configuration
16-3
16.1.2 Port Roles
The MSTP bridge assigns a port role to each port which runs MSTP.
 CIST port roles: Root Port, Designated Port, Alternate Port and Backup Port
 On top of those roles, each MSTI port has one new role: Master Port.
The port roles in the CIST (Root Port, Designated Port, Alternate Port and Backup Port) are defined in the
same ways as those in the RSTP.
16.1.3 MSTP Load Balance
In a MSTP region, VLANs can by mapped to various instances. That can form various topologies. Each
instance is independent from the others and each distance can have its own attributes such as bridge priority
and port cost etc. Consequently, the VLANs in different instances have their own paths. The traffic of the
VLANs are load-balanced.
16.2 MSTP Configuration Task List
MSTP configuration task list:
1. Enable the MSTP and set the running mode
2. Configure instance parameters
3. Configure MSTP region parameters
4. Configure MSTP time parameters
5. Configure the fast migrate feature for MSTP
6. Configure the format of port packet
7. Configure the snooping attribute of authentication key
8. Configure the FLUSH mode once topology changes
1. Enable MSTP and set the running mode
Command Explanation
Global Mode and Port Mode
spanning-tree
no spanning-tree
Enable/Disable MSTP.
Global Mode
spanning-tree mode {mstp|stp|rstp}
no spanning-tree mode
Set MSTP running mode.
Port Mode
spanning-tree mcheck Force port migrate to run under MSTP.