Extreme Networks ExtremeWare XOS 11.3, Manual

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STP Configurations
ExtremeWare XOS 11.3 Concepts Guide
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Figure 32: Multiple STPDs
When the switches in this configuration boot-up, STP configures each STPD such that the topology
contains no active loops. STP could configure the topology in a number of ways to make it loop-free.
In Figure 32 , the connection between switch A and switch B is put into blocking state, and the
connection between switch Y and switch Z is put into blocking state. After STP converges, all the
VLANs can communicate, and all bridging loops are prevented.
The protected VLAN Marketing , which has been assigned to both STPD1 and STPD2, communicates
using all five switches. The topology has no loops, because STP has already blocked the port connection
between switch A and switch B and between switch Y and switch Z.
Within a single STPD, you must be extra careful when configuring your VLANs. Figure 33 illustrates a
network that has been incorrectly set up using a single STPD so that the STP configuration disables the
ability of the switches to forward VLAN traffic.
Sales, Personnel, Marketing
STPD 1 STPD 2
Manufacturing, Engineering, Marketing
Sales, Personnel, Manufacturing, Engineering, Marketing
Switch A Switch Y
Switch Z
Switch M
Switch B
EX_048