Configuring PVST

Enable the user ports on S1, S2, and S3 in access mode.

S1#conf t

S1(config)# int fa0/6

S1(config-if)#no shut

S1(config-if)#switchport mode access

S2#conf t

S2(config)# int fa0/18

S2(config-if)#no shut

S2(config-if)#switchport mode access

S3#conf t

S3(config)# int fa0/11

S3(config-if)#no shut

S3(config-if)#switchport mode access

Create VLANs.

S1#conf t

Enter configuration commands, one per line.  End with CNTL/Z.

S1(config)#vlan 10

S1(config-vlan)#vlan 20

S1(config-vlan)#vlan 30

S1(config-vlan)#vlan 40

S1(config-vlan)#vlan 50

S1(config-vlan)#vlan 60

S1(config-vlan)#vlan 70

S1(config-vlan)#vlan 80

S1(config-vlan)#vlan 99

Using above command create VLANs for S2 & S3.

  Assign VLANs & IP Address to switch ports.

S1(config)#int fa0/6

S1(config-if)#switchport access vlan 30

S1(config)#int vlan 30

S1(config-if)#ip address 172.17.30.1 255.255.255.0

S2(config)#int fa0/18

S2(config-if)#switchport access vlan 20

S2(config)#int vlan 20

S2(config-if)#ip address 172.17.20.1 255.255.255.0

S3(config)#int fa0/11

S3(config-if)#switchport access vlan 10

S3(config)#int vlan 10

S3(config-if)#ip address 172.17.10.1 255.255.255.0

Assign the trunks to native VLAN 99 for all SWs ports F0/1 to F0/4.

S1(config)#int range fa0/1-4

S1(config-if-range)#switchport mode trunk

S1(config-if-range)#switchport trunk native vlan 99

S1(config-if-range)#exit

S1(config)#int vlan 99

S1(config-if)#ip address 172.31.99.1 255.255.255.0

S2(config)#int range fa0/1-4

S2(config-if-range)#switchport mode trunk

S2(config-if-range)#switchport trunk native vlan 99

S2(config-if-range)#exit

S2(config)#int vlan 99

S2(config-if)#ip address 172.31.99.2 255.255.255.0

S3(config)#int range fa0/1-4

S3(config-if-range)#switchport mode trunk

S3(config-if-range)#switchport trunk native vlan 99

S3(config-if-range)#exit

S3(config)#int vlan 99

S3(config-if)#ip address 172.31.99.3 255.255.255.0

Configure STP mode.

 Configure S1 to be the primary root for VLANs 1, 10, 30, 50, and 70. Configure S3 to be the primary root for VLANs 20, 40, 60, 80, and 99. Configure S2 to be the secondary root for all VLANs

S1(config)#spanning-tree mode pvst

S1(config)#spanning-tree vlan 1,10,30,50,70 root primary

S3(config)#spanning-tree mode pvst

S3(config)#spanning-tree vlan 20,40,60,80,99 root  primary

S3(config)#spanning-tree mode pvst

S2(config)# spanning-tree vlan 1,10,20,30,40,50,60,70,80,99 root secondary

 Configure PortFast on the switches.

S1(config-if)#spanning-tree portfast

Configure BPDU guard on the switches.

S1(config-if)#spanning-tree bpduguard enable

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