86 Bridging
Spanning Tree Protocol Entity (STPE)
Spanning Tree Protocol Entity (STPE)
Introduction The Spanning Tree Protocol Entity (STPE) is part of the PathBuilder S200 series
switch Source Route Bridge functionality. The parameters that control Spanning
Tree Protocol operation are in the Bridge Record and Bridge Link Record. In the
Bridge Record, the STPE Control parameter setting determines whether Automatic
or Manual Spanning Tree is used.
For detailed information about the parameters in the Bridge Recor d and in the Bri dge
Link Record, refer to the “Bridge Parameters” an d “Bridge Link Parameters”
sections earlier in this guide.
Automatic
Spanning Tree Automatic Spanning Tree is dynamic and involves more parameters that enable and
control the Spanning Tree Protocol messages that communicate between the bridges.
By processing these messages, the bridges automatically determine a spanning tree
for the network. These messages are continually updated so the spanning tree
automatically adjusts to the current topology. These messages consume a small
amount of the bandwidth. The automatic version is redundant since PathBuilder
S200 series switch has the capability of re-autocalling the destination, thereby
rerouting over another link.
Manual Spanning
Tree Manual Spanning Tree is static and cannot adjust to bridge network topology
changes. However, the process is more straightforward and does not consume
network bandwidth (no Hello frames are used). The Spanning Tree is manually
configured on a bridge link basis using the Bridge Link “STPE Link State”
parameter (FORWARD/BLOCK).
What You Need to
Configure When you configure a node for bridging operation, the spanning tree par ameter s that
appear on the Bridge Parameters Record and Bridge Link Record depend on whether
you configure manual or automatic spanning tree.
Note
All bridges in a network must operate in the same mode, either all automatic or
all manual.
Custom Software
Key One Custom Software Key (CSK) enables both the Source Route Bridging and the
Spanning Tree Protocol Entity.

Configuration

Menu STPE Control= AUTO STPE Control = MANUAL

Bridge Record STPE Control = Auto
Bridge Priority
Max Age
Hello Time
Forward Delay
STPE Control = Manual
Bad Hello Threshold
Bad Hello Count
Bridge Link
Record STPE Priority
STPE Path Cost
STPE Link State