ECS3510-26P_Management Guide R02

C HAPTER 8 | Spanning Tree Algorithm
Configuring Interface Settings for MSTP
– 223 –
CONFIGURING INTERFACE SETTINGS FOR MSTP
Use the Spanning Tree > MSTP (Configure Interface - Configure) page to
configure the STA interface settings for an MST instance.
CLI REFERENCES
◆ "Spanning Tree Commands" on page 795
PARAMETERS
These parameters are displayed:
◆ MST ID – Instance identifier to configure. (Default: 0)
◆ Interface – Displays a list of ports or trunks.
◆ STA Status – Displays the current state of this interface within the
Spanning Tree. (See "Displaying Interface Settings for STA" on
page 217 for additional information.)
■
Discarding – Port receives STA configuration messages, but does
not forward packets.
■
Learning – Port has transmitted configuration messages for an
interval set by the Forward Delay parameter without receiving
contradictory information. Port address table is cleared, and the
port begins learning addresses.
■
Forwarding – Port forwards packets, and continues learning
addresses.
◆ Priority – Defines the priority used for this port in the Spanning Tree
Protocol. If the path cost for all ports on a switch are the same, the port
with the highest priority (i.e., lowest value) will be configured as an
active link in the Spanning Tree. This makes a port with higher priority
less likely to be blocked if the Spanning Tree Protocol is detecting
network loops. Where more than one port is assigned the highest
priority, the port with lowest numeric identifier will be enabled.
(Default: 128; Range: 0-240, in steps of 16)
◆ Admin MST Path Cost – This parameter is used by the MSTP to
determine the best path between devices. Therefore, lower values
should be assigned to ports attached to faster media, and higher values
assigned to ports with slower media. (Path cost takes precedence over
port priority.) Note that when the Path Cost Method is set to short
(page 3-63), the maximum path cost is 65,535.
By default, the system automatically detects the speed and duplex
mode used on each port, and configures the path cost according to the
values shown below. Path cost “0” is used to indicate auto-configuration
mode. When the short path cost method is selected and the default
path cost recommended by the IEEE 8021w standard exceeds 65,535,
the default is set to 65,535