Connectivity Guide

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ethernet1/1/5 Root 128.276 128 500 FWD 0 AUTO No
ethernet1/1/6 Altr 128.280 128 500 BLK 0 AUTO No
Select root bridge
RPVST+ determines the root bridge. Assign one bridge a lower priority to increase the likelihood that it becomes the root bridge. The show
spanning-tree brief command displays information about all ports regardless of the operational status.
• Assign a number as the bridge priority or designate it as the root in CONFIGURATION mode, from 0 to 61440.
spanning-tree {vlan vlan-id priority priority-value}
– vlan-id — Enter a value between 1 to 4093.
– priority priority-value — Enter the priority value in increments of 4096, default is 32768. The lower the number
assigned, the more likely this bridge becomes the root bridge. The bridge priority the valid values are: 0, 4096, 8192, 12288, 16384,
20480, 24576, 28672, 32768, 36864, 40960, 45056, 49152, 53248, 57344, or 61440. All other values are rejected.
Congure root bridge
OS10(config)# spanning-tree vlan 1 priority 4096
View active conguration
OS10(config)# do show spanning-tree active
Spanning tree enabled protocol rapid-pvst with force-version rstp
VLAN 1
Executing IEEE compatible Spanning Tree Protocol
Root ID Priority 4097, Address 90b1.1cf4.a523
Root Bridge hello time 2, max age 20, forward delay 15
Bridge ID Priority 4097, Address 90b1.1cf4.a523
We are the root of VLAN 1
Configured hello time 2, max age 20, forward delay 15
Interface Designated
Name PortID Prio Cost Sts Cost Bridge ID PortID
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ethernet1/1/5 128.276 128 500 FWD 0 4097 90b1.1cf4.a523 128.276
ethernet1/1/6 128.280 128 500 FWD 0 4097 90b1.1cf4.a523 128.280
Interface
Name Role PortID Prio Cost Sts Cost Link-type Edge
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ethernet1/1/5 Desg 128.276 128 500 FWD 0 AUTO No
ethernet1/1/6 Desg 128.280 128 500 FWD 0 AUTO No
View brief conguration
OS10# show spanning-tree brief
Spanning tree enabled protocol rapid-pvst with force-version rstp
VLAN 1
Executing IEEE compatible Spanning Tree Protocol
Root ID Priority 4097, Address 90b1.1cf4.a523
Root Bridge hello time 2, max age 20, forward delay 15
Bridge ID Priority 4097, Address 90b1.1cf4.a523
We are the root of VLAN 1
Configured hello time 2, max age 20, forward delay 15
Interface Designated
Name PortID Prio Cost Sts Cost Bridge ID PortID
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ethernet1/1/1 128.260 128 200000000 FWD 0 32769 0000.0000.0000 128.260
ethernet1/1/2 128.264 128 200000000 FWD 0 32769 0000.0000.0000 128.264
ethernet1/1/3 128.268 128 200000000 FWD 0 32769 0000.0000.0000 128.268
ethernet1/1/4 128.272 128 200000000 FWD 0 32769 0000.0000.0000 128.272
ethernet1/1/5 128.276 128 500 FWD 0 4097 90b1.1cf4.a523 128.276
ethernet1/1/6 128.280 128 500 FWD 0 4097 90b1.1cf4.a523 128.280
ethernet1/1/7 128.284 128 200000000 FWD 0 32769 0000.0000.0000 128.284
ethernet1/1/8 128.288 128 200000000 FWD 0 32769 0000.0000.0000 128.288
ethernet1/1/9 128.292 128 200000000 FWD 0 32769 0000.0000.0000 128.292
Layer 2
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