LevelOne GEL-5261, User Manual

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Chapter 7
| Spanning Tree Algorithm
Configuring Global Settings for STA
preventing wide-scale disruption when a bridge node in a single instance fails,
and allowing for faster convergence of a new topology for the failed instance.
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To allow multiple spanning trees to operate over the network, you must
configure a related set of bridges with the same MSTP configuration,
allowing them to participate in a specific set of spanning tree instances.
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A spanning tree instance can exist only on bridges that have compatible
VLAN instance assignments.
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Be careful when switching between spanning tree modes. Changing
modes stops all spanning-tree instances for the previous mode and restarts
the system in the new mode, temporarily disrupting user traffic.
Parameters
These parameters are displayed:
Basic Configuration of Global Settings
◆ Spanning Tree Status – Enables/disables STA on this switch. (Default: Enabled)
◆ Spanning Tree Type – Specifies the type of spanning tree used on this switch:
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STP : Spanning Tree Protocol (IEEE 802.1D); i.e., when this option is selected,
the switch will use RSTP set to STP forced compatibility mode).
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RSTP : Rapid Spanning Tree (IEEE 802.1w); RSTP is the default.
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MSTP : Multiple Spanning Tree (IEEE 802.1s)
◆ Priority – Bridge priority is used in selecting the root device, root port, and
designated port. The device with the highest priority becomes the STA root
device. However, if all devices have the same priority, the device with the
lowest MAC address will then become the root device. (Note that lower
numeric values indicate higher priority.)
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Default: 32768
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Range: 0-61440, in steps of 4096
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Options: 0, 4096, 8192, 12288, 16384, 20480, 24576, 28672, 32768, 36864,
40960, 45056, 49152, 53248, 57344, 61440
◆ BPDU Flooding – Configures the system to flood BPDUs to all other ports on
the switch or just to all other ports in the same VLAN when spanning tree is
disabled globally on the switch or disabled on a specific port.
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To VLAN: Floods BPDUs to all other ports within the receiving port’s native
VLAN (i.e., as determined by port’s PVID). This is the default.
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To All: Floods BPDUs to all other ports on the switch.
The setting has no effect if BPDU flooding is disabled on a port (see
"Configuring Interface Settings for STA" ).