Figure 127 s – Brocade 6910 Ethernet Access Switch Configuration Guide (Supporting R2.2.0.0) User Manual
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Brocade 6910 Ethernet Access Switch Configuration Guide
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Displaying Interface Settings for STA
•
A port on a network segment with no other STA compliant bridging device is always
forwarding.
•
If two ports of a switch are connected to the same segment and there is no other STA
device attached to this segment, the port with the smaller ID forwards packets and the
other is discarding.
•
All ports are discarding when the switch is booted, then some of them change state to
learning, and then to forwarding.
•
Forward Transitions – The number of times this port has transitioned from the Learning state
to the Forwarding state.
•
Designated Cost – The cost for a packet to travel from this port to the root in the current
Spanning Tree configuration. The slower the media, the higher the cost.
•
Designated Bridge – The bridge priority and MAC address of the device through which this port
must communicate to reach the root of the Spanning Tree.
•
Designated Port – The port priority and number of the port on the designated bridging device
through which this switch must communicate with the root of the Spanning Tree.
•
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 described under
•
Oper Edge Port – This parameter is initialized to the setting for Admin Edge Port in STA Port
Configuration described under
“Configuring Interface Settings for STA”
on page 794 (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 127
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