xStack DES-3500 Series Layer 2 Stackable Fast Ethernet Managed Switch User Manual
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Regulations and Restrictions for the Loopback Detection Function
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All three versions of STP (STP, RSTP and MSTP) can enable this feature.
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May be configured globally (STP Global Bridge Settings), or per port (MSTP Port Information).
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Neighbor switches of DES-3500 Series switches must have the capability to forward BPDU packets. Switches the fail to
meet this requirement will disable this function for the port in question on the DES-3500 Series switches.
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Loopback Detection is globally enabled for the switch, yet the port-by-port default setting is disabled.
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The default setting for the Loopback timer is 60 seconds.
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This setting will only be operational if the interface is STP-enabled.
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The Loopback Detection feature can only prevent BPDU loops on the DES-3500 Series switches designated ports. It can
detect a loop condition occurring on the user’s side connected to the edge port, but it cannot detect the Loopback condition
on the elected root port of STP on another switch.
STP Bridge Global Settings
To open the following window, open the
Spanning Tree
folder in the
Configuration
menu and click the
STP Bridge Global
Settings
link.
Figure 6- 20. STP Bridge Global Settings window - STP
Figure 6- 21. STP Bridge Global Settings window - RSTP (default)