Spanning Tree Algorithm Configuration
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NXA-ENET24 - Software Management Guide
Command Attributes (Cont.)
• Port Role (Cont.) The role is set to disabled (i.e., disabled port) if a port has no role within the spanning
tree.
•Trunk Member: Indicates if a port is a member of a trunk. (STAPort Information only)
These additional parameters are only displayed for the CLI:
• Admin Status: Shows if this interface is enabled.
• Path Cost: 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.)
•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 detect-
ing network loops.
Where more than one port is assigned the highest priority, the port with 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 as Admin Edge port, and is only included for backward
compatibility with earlier products.
• Admin Edge Port: You can enable this option if an interface is attached to a LAN segment that is at the
end of a bridged LAN or to an end node. Since end nodes cannot cause forwarding
loops, they can pass directly through to the spanning tree forwarding state.
Specifying Edge Ports provides quicker convergence for devices such as worksta-
tions or servers, retains the current forwarding database to reduce the amount of
frame flooding required to rebuild address tables during reconfiguration events, does
not cause the spanning tree to initiate reconfiguration when the interface changes
state, and also overcomes other STA-related timeout problems. However, remember
that Edge Port should only be enabled for ports connected to an end-node device.
• Admin Link Type: The link type attached to this interface.
• Point-to-Point – A connection to exactly one other bridge.
• Shared – A connection to two or more bridges.
• Auto – The switch automatically determines if the interface is attached to a point-
to-point link or to shared media.
Alternateport receives more
usefulBPDUs from another
bridgeand is therefore not
selectedas the designated
port.
x
R:Root Port
A:Alternate Port
D:Designated Port
B:Backup Port
RR
ADB
Backupport receives more
usefulBPDUs from the same
bridgeand is therefore not
selectedas the designated
port.
x
RR
ADB