HowTo Configure PVST on Catalyst 2950

[turkminator]

Hello friends,

i got 3 Cisco Catalyst 2950 Switches in front of me and i have to configure Per-VLAN Spanning-Tree.

im a newbie on this topic and hope to get some help.

i have a Serial Cable to link to the PC, HyperTerminal to configure on WinXP, and Ethernet Cables to link the switches.

== first i link the 3 Switches with each other, like:

     SWITCH1 port 22 and SWITCH2 port 22

     SWITCH1 port 23 and SWITCH3 port 23

     SWITCH2 port 24 and SWITCH3 port 24

== then i create VLAN 10,20,30 on all Switches with HyperTerminal

== then i type

     SW1#interface fastEthernet 0/22

     SW1#switchport mode access

     SW1#switchport access vlan 10

     SW2#interface fastEthernet 0/22

     SW2#switchport mode access

     SW2#switchport access vlan 10

     SW1#interface fastEthernet 0/23

     SW1#switchport mode access

     SW1#switchport access vlan 20

     SW3#interface fastEthernet 0/23

     SW3#switchport mode access

     SW3#switchport access vlan 20

     SW2#interface fastEthernet 0/24

     SW2#switchport mode access

     SW2#switchport access vlan 30

     SW3#interface fastEthernet 0/24

     SW3#switchport mode access

     SW3#switchport access vlan 30

== then i type:

SW1#spanning-tree vlan 10 root primary

SW2#spanning-tree vlan 20 root primary

SW3#spanning-tree vlan 30 root primary

== now if i type this..

     SW1#show spanning-tree vlan 10

    .. the terminal returns

     "Spanning-tree instance(s) for vlan 10 does not exist"

i hope to get help

Thank and Greets

Joe

[glen.grant · Accepted solution]

  You are done  with the config...   It doesn't show a spanning tree instance because you have no active ports in those vlans.  You have to have an active device on those ports  or have an active trunk link with those vlans included in it to show an active spanning tree instance. No need for an active spanning tree instance if you have no active ports in those vlans . If you connect all 3 together with trunk links with those 3 vlans allowed across all trunks you will see the spanning tree instances and you will be able to trace the spanning tree roots via the show spanning tree vlan X command. PVST is the default so there is nothing extra you have to configure to have pvst on the switches.

[Alexey Stytsenko]

He had active ports in vlan 10 - SW1 and SW2 interconnected with access ports assigned vlan 10.

I suggests that maybe switches was not on default config.

So i will reccomend to issue following commands (under configuration mode):

spanning-tree mode pvst

spanning-tree vlan 10

Besides i reccomend you to post here outputs of show spanning-tree summary If you will not success agter entering commands i recommend.

[glen.grant]

  If you are having trouble then verify your connecting links show active. Also verify you have created the layer 2 vlan on "all" 3 switches with the "show vlan " command .  Some of the older switches did not create the vlan in the vlan database even though you assigned the vlan to a given port.