Displaying Global Settings
You can display a summary of the current bridge STA information that applies to the
entire switch using the STA Information screen.
Field Attributes
• Spanning Tree State – Shows if the switch is enabled to participate in an
STA-compliant network.
• Bridge ID – A unique identifier for this bri dge, consi sting of the br idge pri ority , the
MST Instance ID 0 for the Common Spanning Tree when spanning tree mode is
set to MSTP (page 10-6), and MAC ad dress (where th e a ddres s is ta ken f rom the
switch system).
• Max Age – The maximum time (in seconds) a device can wai t with out rece iving a
configuration message before attempting to reconfigure. All device ports (except
for designated ports) should receive configuration messages at regula r intervals.
Any port that ages out STA information (provided in the last configuration
message) becomes the designated port for the attached LAN. If it is a root p ort, a
new root port is selected from among the device ports attached to the net work.
(References to “ports” in this section mean “interfaces,” whic h includes both port s
and trunks.)
• Hello Time – Interval (in seconds) at which the root device tr ansmits a
configuration message.
• Forward Delay – The maximum time ( in sec onds) th e root devi ce will wait b efore
changing states (i.e., discarding to learning to forwarding). This delay is required
because every device must receive information about topology changes befor e it
starts to forward frames. In addition, each port needs time to listen for conflicting
information that would make it return to a discarding state; otherwise, temporary
data loops might result.
• Designated Root – The priority and MAC ad dress of th e device in th e Spannin g
Tree that this switch has accepted as the root device.
-
Root Port
– The number of the port on this switch that is closest to the root. This
switch communicates with the root device through this port. If th ere is no r oot
port, then this switch has been accepted as the root device of the Spanning Tree
network.
- Root Path Cost – The path cost from the root port on this switch to the root
device.
• Configuration Changes – The number of ti mes the Sp annin g Tree has been
reconfigured.
• Last Topology Change – Ti me since the Spanning Tree was last r econfigured .
These additional parameters are only displayed for the CLI:
• Spanning tree mode – Specifies the type o f spanni ng tree used on this swi tch:
- STP: Spanning Tree Protocol (IEEE 802.1D )
- RSTP: Rapid Spanning Tree (IEEE 802. 1w)
- MSTP: Multiple Spanning Tree (IEEE 802.1 s)

10-3

Displaying Global Settings

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