Microsens MS453490M Management Guide - Manual (Page 208)

C HAPTER 8 | Spanning Tree Algorithm
Displaying Interface Settings for STA
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◆ Oper Path Cost – The contribution of this port to the path cost of
paths towards the spanning tree root which include this port.
◆ Oper Link Type – The operational point-to-point status of the LAN
segment attached to this interface. This parameter is determined by
manual configuration or by auto-detection, as described for Admin Link
Type in STA Port Configuration on page 203 .
◆ Oper Edge Port – This parameter is initialized to the setting for Admin
Edge Port in STA Port Configuration on page 203 (i.e., true or false),
but will be set to false if a BPDU is received, indicating that another
bridge is attached to this port.
◆ Port Role – Roles are assigned according to whether the port is part of
the active topology connecting the bridge to the root bridge (i.e., root
port), connecting a LAN through the bridge to the root bridge (i.e.,
designated port), is the MSTI regional root (i.e., master port), or is
an alternate or backup port that may provide connectivity if other
bridges, bridge ports, or LANs fail or are removed. The role is set to
disabled (i.e., disabled port) if a port has no role within the spanning
tree.
Figure 99: STA Port Roles
Alternate port receives more
useful BPDUs from another
bridge and is therefore not
selected as the designated
port.
x
R: Root Port
A: Alternate Port
D: Designated Port
B: Backup Port
R R
A D B
Backup port receives more
useful BPDUs from the same
bridge and is therefore not
selected as the designated
port.
x
R R
A D B