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| Sun Ethernet Fabric Operating System ### STP Administration Guide

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## Configure the Topology

See RSTP Configuration Guidelines for the topology setup. By default, all the switches run MSTP.

1. Change the STP mode to RSTP in switches 1 and 2.

       SEFOS# configure terminal
       SEFOS(config)# spanning-tree mode rstp
       SEFOS(config)# end

2. Change the STP mode to RSTP in switch 3.

       SEFOS# configure terminal
       SEFOS(config)# spanning-tree mode rstp
       SEFOS(config)# spanning-tree priority 0
       SEFOS(config)# end

   Note - Switch 3 is now the root of the spanning tree because the bridge priority is lesser than the other bridges on the spanning tree.

3. View the spanning tree port roles and port states after 22 seconds.
   1. In switch 1, type.

          SEFOS# show spanning-tree

          Root Id         Priority   0
                          Address    00:03:02:03:04:01
                          Cost       200000
                          Port       Ex0/2
                          Hello Time 2 Sec, Max Age 20 Sec, Forward Delay 15 Sec
          Bridge is executing the rstp compatible Spanning Tree Protocol
          Bridge Id       Priority 32768
                          Address 00:01:02:03:04:01
                          Hello Time 2 sec, Max Age 20 sec, Forward Delay 15 sec
              Name     Role         State        Cost     Prio   Type
              ----     ----         -----        ----     ----   ------
          Ex0/1    Designated   Forwarding   200000   128    SharedLan
          Ex0/2    Root         Forwarding   200000   128    SharedLan

   2. In switch 2, type.

          SEFOS# show spanning-tree

          Root Id         Priority   0
                          Address    00:03:02:03:04:01
                          Cost       200000
                          Port       Ex0/2
                          Hello Time 2 Sec, Max Age 20 Sec, Forward Delay 15 Sec
          Bridge is executing the rstp compatible Spanning Tree Protocol
          Bridge Id       Priority 32768
                          Address 00:02:02:03:04:01
                          Hello Time 2 sec, Max Age 20 sec, Forward Delay 15 sec
          Name     Role         State        Cost     Prio   Type
          ----     ----         -----        ----     ----   ------
          Ex0/1    Alternate    Discarding   200000   128    SharedLan
          Ex0/2    Root         Forwarding   200000   128    SharedLan

   3. In switch 3, type.

          SEFOS# show spanning-tree

          We are the root of the Spanning Tree
          Root Id         Priority   0
                          Address    00:03:02:03:04:01
                          Cost       0
                          Port       0
                          Hello Time 2 Sec, Max Age 20 Sec, Forward Delay 15 Sec
          Bridge is executing the rstp compatible Spanning Tree Protocol
          Bridge Id       Priority 0
                          Address 00:03:02:03:04:01
                          Hello Time 2 sec, Max Age 20 sec, Forward Delay 15 sec
              Name     Role         State        Cost     Prio   Type
              ----     ----         -----        ----     ----   ------
          Ex0/1    Designated   Forwarding   200000   128    SharedLan
          Ex0/2    Designated   Forwarding   200000   128    SharedLan

4. Configure the port path cost for port P2 on switch 2 as 4094.

       SEFOS# configure terminal
       SEFOS(config)# interface extreme-ethernet 0/2
       SEFOS(config-if)# spanning-tree cost 4094
       SEFOS(config-if)# end

   Note - This command configures port P1 of switch 2 as designated and port P1 of switch 1 as alternate.

5. View the spanning tree port roles and port states after 22 seconds.
   1. In switch 1, type.

          SEFOS# show spanning-tree

          Root Id         Priority   0                Address    00:03:02:03:04:01                Cost       200000                Port       Ex0/2                Hello Time 2 Sec, Max Age 20 Sec, Forward Delay 15 SecBridge is executing the rstp compatible Spanning Tree ProtocolBridge Id       Priority 32768                Address 00:01:02:03:04:01                Hello Time 2 sec, Max Age 20 sec, Forward Delay 15 sec    Name     Role         State        Cost     Prio   Type    ----     ----         -----        ----     ----   ------Ex0/1    Alternate    Discarding   200000   128    SharedLanEx0/2    Root         Forwarding   200000   128    SharedLan

   2. In switch 2, type.

          SEFOS# show spanning-tree

          Root Id         Priority   0
                          Address    00:03:02:03:04:01
                          Cost       4094
                          Port       Ex0/2
                          Hello Time 2 Sec, Max Age 20 Sec, Forward Delay 15 Sec
          Bridge is executing the rstp compatible Spanning Tree Protocol
          Bridge Id       Priority 32768
                          Address 00:02:02:03:04:01
                          Hello Time 2 sec, Max Age 20 sec, Forward Delay 15 sec
              Name     Role         State        Cost     Prio   Type
              ----     ----         -----        ----     ----   ------
          Ex0/1    Designated   Forwarding   200000   128    SharedLan
          Ex0/2    Root         Forwarding   4094     128    SharedLan

   3. In switch 3, type.

          SEFOS# show spanning-tree

          We are the root of the Spanning Tree
          Root Id         Priority   0
                          Address    00:03:02:03:04:01
                          Cost       0
                          Port       0
                          Hello Time 2 Sec, Max Age 20 Sec, Forward Delay 15 Sec
          Bridge is executing the rstp compatible Spanning Tree Protocol
          Bridge Id       Priority 0
                          Address 00:03:02:03:04:01
                          Hello Time 2 sec, Max Age 20 sec, Forward Delay 15 sec
              Name     Role         State        Cost     Prio   Type
              ----     ----         -----        ----     ----   ------
          Ex0/1    Designated   Forwarding   200000   128    SharedLan
          Ex0/2    Designated   Forwarding   200000   128    SharedLan

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