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Spanning Tree does not work on Cisco 3550 Switch

Phantom914Phantom914 Member Posts: 9 ■□□□□□□□□□
in CCNA & CCENT
I bought a stack of used routers and switches recently, and I've been studying for my CCNA exam. The problem is when I got to lab 5.5.2 in the switching lab book my 3550 switch could not use spanning tree anymore. 5.5.1 worked no problem, but for some reason my switch can not use or see any spanning tree. It just keeps saying "No instance of spanning tree." I googled the problem already, and my ports and VLANs and everything is on. Can someone help please?
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    MAC_AddyMAC_Addy Member Posts: 1,740 ■■■■□□□□□□
    What have you done to configure STP on your switches? Also, if you'd post the running-configs, that would help a lot.
    2017 Certification Goals:
    CCNP R/S
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    TheNewITGuyTheNewITGuy Member Posts: 169 ■■■■□□□□□□
    spanning-tree may not show a running instance because there is no stp topology setup. (ie: no need for spanning tree)
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    Donnelly82Donnelly82 Member Posts: 39 ■■■□□□□□□□
    heres my 3350 spanning-tree...



    Switch_3550#show spanning-tree

    VLAN0001
    Spanning tree enabled protocol rstp
    Root ID Priority 32769
    Address 0009.e83f.ef00
    This bridge is the root
    Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

    Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
    Address 0009.e83f.ef00
    Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
    Aging Time 300 sec

    Interface Role Sts Cost Prio.Nbr Type
    ---- ---
    Fa0/1 Desg FWD 19 128.1 P2p Edge
    Fa0/2 Desg FWD 19 128.2 P2p Edge
    Fa0/12 Desg FWD 19 128.12 P2p Edge
    Fa0/13 Desg FWD 19 128.13 P2p
    Fa0/24 Desg FWD 19 128.24 P2p



    Running config
    ........
    spanning-tree mode rapid-pvst
    spanning-tree etherchannel guard misconfig
    spanning-tree extend system-id
    !
    vlan internal allocation policy ascending
    !
    ip tcp synwait-time 5
    ip ssh version 2

    interface FastEthernet0/13
    switchport trunk encapsulation dot1q
    switchport mode trunk
    !

    interface FastEthernet0/24
    switchport trunk encapsulation dot1q
    switchport mode trunk

    hopefully some of this info will help??
    all the best
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    xXErebuSxXErebuS Member Posts: 230
    Is there a link between the switch on Fa0/13 and the switch on Fa0/24?
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    Architect192Architect192 Member Posts: 157 ■■■□□□□□□□
    How are your switches wired together? What is the configuration of the other switch?
    Current: VCAP-DCA/DCD, VCP-DCV2/3/4/5, VCP-NV 6 - CCNP, CCNA Security - MCSE: Server Infrastructure 2012 - ITIL v3 - A+ - Security+
    Working on: CCNA Datacenter (2nd exam), Renewing VMware certs...
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    Phantom914Phantom914 Member Posts: 9 ■□□□□□□□□□

    This is my wiring and here is the Running Config:
    S3#sh run
    Building configuration...


    Current configuration : 2543 bytes
    !
    version 12.1
    no service pad
    service timestamps debug uptime
    service timestamps log uptime
    no service password-encryption
    !
    hostname S3
    !
    !
    ip subnet-zero
    !
    no ip domain-lookup
    ip ssh time-out 120
    ip ssh authentication-retries 3
    !
    spanning-tree mode pvst
    spanning-tree extend system-id
    !
    !
    !
    !
    !
    interface FastEthernet0/1
    switchport trunk native vlan 99
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/2
    switchport trunk native vlan 99
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/3
    switchport trunk native vlan 99
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/4
    switchport trunk native vlan 99
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/5
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/6
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/7
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/8
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/9
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/10
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/11
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/12
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/13
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/14
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/15
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/16
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/17
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/18
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/19
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/20
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/21
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/22
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/23
    switchport mode dynamic desirable
    shutdown
    !
    interface FastEthernet0/24
    switchport mode dynamic desirable
    shutdown
    !
    interface GigabitEthernet0/1
    switchport mode dynamic desirable
    !
    interface GigabitEthernet0/2
    switchport mode dynamic desirable
    !
    interface Vlan1
    no ip address
    shutdown
    !
    interface Vlan99
    ip address 172.17.99.13 255.255.255.0
    !
    ip classless
    ip http server
    !
    !
    line con 0
    logging synchronous
    line vty 0 4
    login
    line vty 5 15
    login
    !
    !
    end

    What happens when I try to show spanning tree after enabling it.

    S3#sh spanning-tree


    No spanning tree instance exists.


    S3#conf t
    Enter configuration commands, one per line. End with CNTL/Z.
    S3(config)#spanning-tree vlan 99
    S3(config)#^Z
    S3#
    00:09:23: %SYS-5-CONFIG_I: Configured from console by console
    S3#sh spanning-tree


    No spanning tree instance exists.


    S3#conf t
    Enter configuration commands, one per line. End with CNTL/Z.
    S3(config)#spanning-tree vlan 10
    S3(config)#^Z
    00:12:57: %SYS-5-CONFIG_I: Configured from console by console
    S3#show spanning-t


    No spanning tree instance exists

    VLAN Brief:
    S3#show vlan br

    VLAN Name Status Ports
    ----
    1 default active Fa0/1, Fa0/2, Fa0/3, Fa0/4
    Fa0/5, Fa0/6, Fa0/7, Fa0/8
    Fa0/9, Fa0/10, Fa0/11, Fa0/12
    Fa0/13, Fa0/14, Fa0/15, Fa0/16
    Fa0/17, Fa0/18, Fa0/19, Fa0/20
    Fa0/21, Fa0/22, Fa0/23, Fa0/24
    Gi0/1, Gi0/2
    10 faculty-staff active
    20 students active
    30 guest active
    99 management active
    1002 fddi-default act/unsup
    1003 token-ring-default act/unsup
    1004 fddinet-default act/unsup
    1005 trnet-default act/unsup
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    Architect192Architect192 Member Posts: 157 ■■■□□□□□□□
    What about S1 and S2? Spanning tree will come up when there is a loop created. Are your interfaces Fa0/1-0/4 up? You're showing us the VLAN status but the interfaces must be live and communicating.

    EDIT: I just rechecked your configuration: Ports 1-4 are all shutdown...
    Current: VCAP-DCA/DCD, VCP-DCV2/3/4/5, VCP-NV 6 - CCNP, CCNA Security - MCSE: Server Infrastructure 2012 - ITIL v3 - A+ - Security+
    Working on: CCNA Datacenter (2nd exam), Renewing VMware certs...
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    networker050184networker050184 Mod Posts: 11,962 Mod
    Architect192 wrote: »
    Spanning tree will come up when there is a loop created.

    That is not ture. You do not need a loop for STP to start. Just a port in the up condition assigned to an existing VLAN.
    An expert is a man who has made all the mistakes which can be made.
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    thinguythinguy Member Posts: 22 ■□□□□□□□□□
    What do the other switches say about STP status?
    Do all of them have "spanning-tree extend system-id" set? Try removing that.
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    Architect192Architect192 Member Posts: 157 ■■■□□□□□□□
    networker050184 wrote: »
    That is not ture. You do not need a loop for STP to start. Just a port in the up condition assigned to an existing VLAN.

    True, my mistake. Possibility of a loop, not an actual loop. (if all ports are shutdown like in the OP's config, this condition doesnt exist so STP doesn't come up).
    Current: VCAP-DCA/DCD, VCP-DCV2/3/4/5, VCP-NV 6 - CCNP, CCNA Security - MCSE: Server Infrastructure 2012 - ITIL v3 - A+ - Security+
    Working on: CCNA Datacenter (2nd exam), Renewing VMware certs...
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    Phantom914Phantom914 Member Posts: 9 ■□□□□□□□□□
    I actually posted the wrong config, but it wasn't fully wrong. I guess I didn't copy the run that day. I'll post a lot more info after work.
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    networker050184networker050184 Mod Posts: 11,962 Mod
    Post the output of show ip interface brief.
    An expert is a man who has made all the mistakes which can be made.
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    Phantom914Phantom914 Member Posts: 9 ■□□□□□□□□□
    Ok, so I don't know if you'll all be mad, but it worked somehow.

    S3(config-if-range)#no shut
    S3(config-if-range)#
    00:01:23: %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to up
    00:01:23: %LINK-3-UPDOWN: Interface FastEthernet0/2, changed state to up
    00:01:23: %LINK-3-UPDOWN: Interface FastEthernet0/3, changed state to up
    00:01:23: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
    S3(config-if-range)#
    00:01:27: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, chang
    ed state to up
    00:01:27: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, chang
    ed state to up
    00:01:27: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/3, chang
    ed state to up
    00:01:27: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
    ed state to up
    S3(config-if-range)#^Z
    S3#
    00:01:30: %SYS-5-CONFIG_I: Configured from console by console
    S3#conf t
    Enter configuration commands, one per line. End with CNTL/Z.
    S3(config)#spanning-tree vlan 99
    S3(config)#^Z
    00:01:51: %SYS-5-CONFIG_I: Configured from console by console
    S3#sh spanning-t


    VLAN0001
    Spanning tree enabled protocol ieee
    Root ID Priority 32769
    Address 0008.2058.0fc0
    Cost 19
    Port 3 (FastEthernet0/3)
    Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec


    Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)
    Address 0011.20c2.b600
    Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
    Aging Time 15


    Interface Role Sts Cost
    00:01:57: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan99, changed state
    to up Prio.Nbr Type
    ---- ---
    Fa0/1 Altn BLK 19 128.1 P2p
    Fa0/2 Altn BLK 19 128.2 P2p
    Fa0/3 Root FWD 19 128.3 P2p
    Fa0/4 Altn BLK 19 128.4 P2p




    VLAN0010
    Spanning tree enabled protocol ieee
    Root ID Priority 32778
    Address 0008.2058.0fc0
    Cost 19
    Port 3 (FastEthernet0/3)
    Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec


    Bridge ID Priority 32778 (priority 32768 sys-id-ext 10)
    Address 0011.20c2.b600
    Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
    Aging Time 15


    Interface Role Sts Cost Prio.Nbr Type
    ---- ---
    Fa0/1 Altn BLK 19 128.1 P2p
    Fa0/2 Altn BLK 19 128.2 P2p
    Fa0/3 Root FWD 19 128.3 P2p
    Fa0/4 Altn BLK 19 128.4 P2p




    VLAN0020
    Spanning tree enabled protocol ieee
    Root ID Priority 32788
    Address 0008.2058.0fc0
    Cost 19
    Port 3 (FastEthernet0/3)
    Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec


    Bridge ID Priority 32788 (priority 32768 sys-id-ext 20)
    Address 0011.20c2.b600
    Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
    Aging Time 15


    Interface Role Sts Cost Prio.Nbr Type
    ---- ---
    Fa0/1 Altn BLK 19 128.1 P2p
    Fa0/2 Altn BLK 19 128.2 P2p
    Fa0/3 Root FWD 19 128.3 P2p
    Fa0/4 Altn BLK 19 128.4 P2p




    VLAN0030
    Spanning tree enabled protocol ieee
    Root ID Priority 32798
    Address 0008.2058.0fc0
    Cost 19
    Port 3 (FastEthernet0/3)
    Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec


    Bridge ID Priority 32798 (priority 32768 sys-id-ext 30)
    Address 0011.20c2.b600
    Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
    Aging Time 15


    Interface Role Sts Cost Prio.Nbr Type
    ---- ---
    Fa0/1 Altn BLK 19 128.1 P2p
    Fa0/2 Altn BLK 19 128.2 P2p
    Fa0/3 Root FWD 19 128.3 P2p
    Fa0/4 Altn BLK 19 128.4 P2p




    VLAN0099
    Spanning tree enabled protocol ieee
    Root ID Priority 32867
    Address 0008.2058.0fc0
    Cost 19
    Port 3 (FastEthernet0/3)
    Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec


    Bridge ID Priority 32867 (priority 32768 sys-id-ext 99)
    Address 0011.20c2.b600
    Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
    Aging Time 15


    Interface Role Sts Cost Prio.Nbr Type
    ---- ---
    Fa0/1 Altn BLK 19 128.1 P2p
    Fa0/2 Altn BLK 19 128.2 P2p
    Fa0/3 Root FWD 19 128.3 P2p
    Fa0/4 Altn BLK 19 128.4 P2p


    S3#conf t
    Enter configuration commands, one per line. End with CNTL/Z.
    S3(config)#^Z
    S3#show
    00:02:28: %SYS-5-CONFIG_I: Configured from console by console
    S3#show vlan brief


    VLAN Name Status Ports
    ----
    1 default active Fa0/5, Fa0/6, Fa0/7, Fa0/8
    Fa0/9, Fa0/10, Fa0/11, Fa0/12
    Fa0/13, Fa0/14, Fa0/15, Fa0/16
    Fa0/17, Fa0/18, Fa0/19, Fa0/20
    Fa0/21, Fa0/22, Fa0/23, Fa0/24
    Gi0/1, Gi0/2
    10 faculty-staff active
    20 students active
    30 guest active
    99 management active
    1002 fddi-default act/unsup
    1003 token-ring-default act/unsup
    1004 fddinet-default act/unsup
    1005 trnet-default act/unsup
    S3#sh ip int brief
    Interface IP-Address OK? Method Status Prot
    ocol
    Vlan1 unassigned YES NVRAM administratively down down


    Vlan99 172.17.99.13 YES NVRAM up up


    FastEthernet0/1 unassigned YES unset up up


    FastEthernet0/2 unassigned YES unset up up


    FastEthernet0/3 unassigned YES unset up up


    FastEthernet0/4 unassigned YES unset up up


    FastEthernet0/5 unassigned YES unset administratively down down


    FastEthernet0/6 unassigned YES unset administratively down down


    FastEthernet0/7 unassigned YES unset administratively down down


    FastEthernet0/8 unassigned YES unset administratively down down


    FastEthernet0/9 unassigned YES unset administratively down down


    FastEthernet0/10 unassigned YES unset administratively down down


    FastEthernet0/11 unassigned YES unset administratively down down


    FastEthernet0/12 unassigned YES unset administratively down down


    FastEthernet0/13 unassigned YES unset administratively down down


    FastEthernet0/14 unassigned YES unset administratively down down


    FastEthernet0/15 unassigned YES unset administratively down down


    FastEthernet0/16 unassigned YES unset administratively down down


    FastEthernet0/17 unassigned YES unset administratively down down


    FastEthernet0/18 unassigned YES unset administratively down down


    FastEthernet0/19 unassigned YES unset administratively down down


    FastEthernet0/20 unassigned YES unset administratively down down


    FastEthernet0/21 unassigned YES unset administratively down down


    FastEthernet0/22 unassigned YES unset administratively down down


    FastEthernet0/23 unassigned YES unset administratively down down


    FastEthernet0/24 unassigned YES unset administratively down down


    GigabitEthernet0/1 unassigned YES unset down down


    GigabitEthernet0/2 unassigned YES unset down down

    And yes it says Fa0/1 - 4 are up now, which I definitely did fix last time I tried to make spanning tree work. I don't know, maybe the auto trunking isn't working correctly on this switch?
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    iamme4evaiamme4eva Member Posts: 272
    +1 for what networker said. Proof that STP works without a loop is to take a switch, clear the configs, plug just one host into it. It will take 30 secs before the light goes green. That's the spanning-tree instance for VLAN 1 doing it's job.

    Phantom, there is no need to enable spanning tree per VLAN...I see you keep doing this:
    S3(config)#spanning-tree vlan 99
    S3(config)#^Z

    When you run PVST, a spanning tree instance is automagically created for every VLAN on the switch which has an active port in it.
    Current objective: CCNA Security
    My blog: mybraindump.co.uk
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    HondabuffHondabuff Member Posts: 667 ■■■□□□□□□□
    I would change Switch(config)#no spanning-tree portfast default or do a erase startup-config and reload. Looks like you have rapid spanning tree enabled globally on the switch.
    “The problem with quotes on the Internet is that you can’t always be sure of their authenticity.” ~Abraham Lincoln
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    networker050184networker050184 Mod Posts: 11,962 Mod
    Phantom914 wrote: »
    Ok, so I don't know if you'll all be mad, but it worked somehow.

    The somehow is this.
    Phantom914 wrote: »
    S3(config-if-range)#no shut
    S3(config-if-range)#
    00:01:23: %LINK-3-UPDOWN: Interface FastEthernet0/1, changed state to up
    00:01:23: %LINK-3-UPDOWN: Interface FastEthernet0/2, changed state to up
    00:01:23: %LINK-3-UPDOWN: Interface FastEthernet0/3, changed state to up
    00:01:23: %LINK-3-UPDOWN: Interface FastEthernet0/4, changed state to up
    S3(config-if-range)#
    00:01:27: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/1, chang
    ed state to up
    00:01:27: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/2, chang
    ed state to up
    00:01:27: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/3, chang
    ed state to up
    00:01:27: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/4, chang
    ed state to up

    You don't need this.
    Phantom914 wrote: »
    S3(config-if-range)#^Z
    S3#
    00:01:30: %SYS-5-CONFIG_I: Configured from console by console
    S3#conf t
    Enter configuration commands, one per line. End with CNTL/Z.
    S3(config)#spanning-tree vlan 99
    S3(config)#^Z
    00:01:51: %SYS-5-CONFIG_I: Configured from console by console

    All you need is a port in the 'up' state and STP kicks in by default.
    An expert is a man who has made all the mistakes which can be made.
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    Phantom914Phantom914 Member Posts: 9 ■□□□□□□□□□
    iamme4eva wrote: »
    +1 for what networker said. Proof that STP works without a loop is to take a switch, clear the configs, plug just one host into it. It will take 30 secs before the light goes green. That's the spanning-tree instance for VLAN 1 doing it's job.

    Phantom, there is no need to enable spanning tree per VLAN...I see you keep doing this:



    When you run PVST, a spanning tree instance is automagically created for every VLAN on the switch which has an active port in it.

    I was only doing that because there was no spanning tree working before. The auto trunk/switchport thing on it wasn't working correctly, I think because I had one switch as a server for VTP and 2 as clients. my other switch that I need to set the trunk got the info, but this 3550 wasn't getting it even with the trunk ports on.
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    networker050184networker050184 Mod Posts: 11,962 Mod
    That is because the trunk ports were not up. As soon as they come up the STP instance kicks in.
    An expert is a man who has made all the mistakes which can be made.
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