S
PANNING
T
REE
A
LGORITHM
C
ONFIGURATION
3-129
Trunk Member – Indicates if a port is a member of a trunk.
(STA Port Information only)
These additional parameters are only displayed for the CLI:
• Admin status – Shows if this interface is enabled.
• External path cost – The path cost for the IST. This parameter is
used by the STA 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.)
• Internal path cost – The path cost for the MST. See the proceeding
item.
• Priority – Defines the priority used for this port in the Spanning Tree
Algorithm. If the path cost for all ports on a switch is 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 Algorithm is
detecting network loops. Where more than one port is assigned the
highest priority, the port with the lowest numeric identifier will be
enabled.
• Designated root – The priority and MAC address of the device in the
Spanning Tree that this switch has accepted as the root device.
• Fast forwarding – This field provides the same information as Admin
Edge port, and is only included for backward compatibility with earlier
products.
Backup port receives more
useful BPDUs from the same
bridge and is therefore not
selected as the designated
port.
x
RR
ADB