VLAN being pruned from Spanning tree root port!

[marioderosa2008]

Hi all,

has anyone ever come accross an issue with the root port for a certain vlan does not seem to be forwarding traffic for that vlan becuase the vlan is being pruned by VTP on the link?

I can see MAC addresses being learned from the root port in this specific VLAN, but we are having communication issues.

I can see that the spanning-tree root port is the correct port, closest to the root bridge, but when i look at the vlans being trunked, i can see tht the vlan is being pruned from the trunk!

I have disabled vtp pruning frm the trunk and still the same issue

I then noticed that VLAN 1 was not being explicitly allowed on the trunk, so I have allowed vlan 1 on the trunk now too and the vlan is still getting pruned!

VTP is working as I have added a new vlan on the server and the client still received the vlan update and has increased it vtp revision number etc...

is there anything else that I should be looking at?

Thanks

Mario

[Furose M]

Hi,

could you show us a simple topology with where the VTP server/clients are localted along with the STP role and states?

what is the output of "show inter prun" on the switch where the VLAN is being pruned?

do we see VLAN 1 being allowed in the peer switch? what is the VTP mode in the peer switch? is VLAN 1 the native-vlan?

[paul driver]

Hello
Usually vlan pruning occurs when the vlan in question isn't being utilised on a specific switch-meaning it doesn't have any ports utilising that specific vlan.

Also Vlan 1, 1002 + don't participate in vtp pruning

Res
Paul


Sent from Cisco Technical Support iPad App

[marioderosa2008]

From the output below you can see that gi5/2 is the root port for vlan 10, there are active ports in vlan 10, vlan 10 has been allowed on the trunk, vlan pruning has been disabled on that port, but vlan 10 is still being pruned...

Hope this helps

RU-core-1-6506#show int gi5/2 pruning

Port            Vlans pruned for lack of request by neighbor

Gi5/2           9-10,92,132,240,400-401,600-603,810

Port                Vlan traffic requested of neighbor

Gi5/2               1,9-10,30-31,34,40,50,60,70,80,89-90,92,131-132,240,400-401,667,803,810,910-912,920-921,930

RU-core-1-6506#show int gi5/2 trunk

Port                Mode         Encapsulation  Status        Native vlan

Gi5/2               on           802.1q         trunking      1

Port                Vlans allowed on trunk

Gi5/2               1,9-10,30-31,34,40,50,60,70,80,89-90,92,131-132,240,400-401,600-603,667,803,810,910-912,920-921,930

Port                Vlans allowed and active in management domain

Gi5/2               1,9-10,30-31,34,40,50,60,70,80,89-90,92,131-132,240,400-401,600-603,667,803,810,910-912,920-921,930

Port                Vlans in spanning tree forwarding state and not pruned

Gi5/2               1,30-31,34,40,50,60,70,80,89-90,131,667,803,910-912,920-921,930

RU-core-1-6506#show spann

RU-core-1-6506#show spanning-tree vlan 10

VLAN0010

  Spanning tree enabled protocol rstp

  Root ID    Priority    16394

             Address     001f.6d1a.a400

             Cost        3

             Port        514 (GigabitEthernet5/2)

             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32778  (priority 32768 sys-id-ext 10)

             Address     c47d.4f8c.8480

             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

             Aging Time 300

Interface           Role Sts Cost      Prio.Nbr Type

------------------- ---- --- --------- -------- --------------------------------

Gi1/4               Desg FWD 4         128.4    P2p

Gi1/22              Desg FWD 4         128.22   P2p

Gi1/41              Desg FWD 4         128.41   P2p

Gi1/42              Desg FWD 4         128.42   P2p

Gi1/43              Desg FWD 4         128.43   P2p

Gi1/44              Desg FWD 19        128.44   P2p

Gi3/3               Desg FWD 19        128.259  P2p

Interface           Role Sts Cost      Prio.Nbr Type

------------------- ---- --- --------- -------- --------------------------------

Gi3/4               Desg FWD 19        128.260  P2p

Gi3/11              Desg FWD 4         128.267  P2p

Gi3/16              Desg FWD 4         128.272  P2p Edge

Gi3/19              Desg FWD 4         128.275  P2p Edge

Gi3/20              Desg FWD 19        128.276  P2p Edge

Gi3/22              Desg FWD 4         128.278  P2p

Gi3/23              Desg FWD 4         128.279  P2p

Gi3/24              Desg FWD 4         128.280  P2p

Gi3/30              Desg FWD 4         128.286  P2p Edge

Gi3/31              Desg FWD 4         128.287  P2p Edge

Gi3/32              Desg FWD 4         128.288  P2p Edge

Gi3/33              Desg FWD 4         128.289  P2p Edge

Gi3/34              Desg FWD 4         128.290  P2p Edge

Gi3/35              Desg FWD 4         128.291  P2p Edge

Gi3/36              Desg FWD 4         128.292  P2p Edge

Gi3/37              Desg FWD 4         128.293  P2p Edge

Gi3/38              Desg FWD 4         128.294  P2p Edge

Gi3/39              Desg FWD 4         128.295  P2p Edge

Gi3/40              Desg FWD 4         128.296  P2p

Gi3/42              Desg FWD 4         128.298  P2p

Gi3/43              Desg FWD 19        128.299  P2p

Gi3/48              Desg FWD 8         128.304  P2p

Gi5/2               Root FWD 2         128.514  P2p

Interface           Role Sts Cost      Prio.Nbr Type

------------------- ---- --- --------- -------- --------------------------------

Po2                 Desg FWD 3         128.1667 P2p

Po63                Desg FWD 1         128.1668 P2p

RU-core-1-6506#show vlan

VLAN Name                             Status    Ports

---- -------------------------------- --------- -------------------------------

1    default                          active    Gi1/5, Gi1/6, Gi1/7, Gi3/41

                                                Gi5/3

2    mario-test                       active

9    SHR-Servers                      active

10   Tempsford_Lan                    active    Gi1/25, Gi1/41, Gi1/42, Gi1/43

                                                Gi1/44, Gi3/1, Gi3/3, Gi3/4

                                                Gi3/5, Gi3/11, Gi3/13, Gi3/15

                                                Gi3/20, Gi3/40, Gi3/42, Gi3/43

RU-core-1-6506#sh run int gi5/2

Building configuration...

Current configuration : 478 bytes

!

interface GigabitEthernet5/2

description Link to Tempsford - TH_DC_core_02

switchport

switchport trunk encapsulation dot1q

switchport trunk allowed vlan 1,9,10,30,31,34,40,50,60,70,80,89,90,92,131,132

switchport trunk allowed vlan add 240,400,401,600-603,667,803,810,910-912,920

switchport trunk allowed vlan add 921,930

switchport trunk pruning vlan none

switchport mode trunk

mtu 9216

spanning-tree vlan 1,9-10,92,132,240,401,810 cost 2

spanning-tree cost 6

end

RU-core-1-6506#

[Furose M]

whats the VTP mode on the peer and this switch?

[marioderosa2008]

the vtp mode of the peer is server and this switch is a client.

[Jon Marshall]

Mario

What model is this switch ?

What is the switch at the other end ?

Where are the non local vlan 10 clients ie are they connected to the neighboring switch ?

What do the same outputs as you have posted look like on the neighboring switch ?

Jon

[marioderosa2008]

apologies for the delay is responding Jon...

this was taken out of my hands and a TAC case raised and Cisco have recommended that VTP is confused and have suggested a couple of steps to refresh VTP...

the first being to change the VTP mode from client to transparent then back to client..

if that is unsuccessful, then we should reboot the switch.. we are doing this today so I should hopefully have a positive update in a while.

to answer your questions...

the local switch which is pruning vlans show ver output is below... the neighboring switch is a 6509 with the same sup and IOS

RU-core-1-6506#show ver
Cisco IOS Software, s72033_rp Software (s72033_rp-ADVIPSERVICESK9_WAN-M), Version 12.2(33)SXI12, RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2013 by Cisco Systems, Inc.
Compiled Fri 30-Aug-13 16:07 by prod_rel_team

ROM: System Bootstrap, Version 12.2(17r)SX6, RELEASE SOFTWARE (fc1)

RU-core-1-6506 uptime is 13 weeks, 2 days, 16 hours, 24 minutes
Uptime for this control processor is 13 weeks, 2 days, 16 hours, 15 minutes
Time since RU-core-1-6506 switched to active is 13 weeks, 2 days, 16 hours, 15 minutes
System returned to ROM by reload at 20:02:42 gmt Thu Nov 28 2013 (SP by reload)
System restarted at 20:05:34 gmt Thu Nov 28 2013
System image file is "sup-bootdisk:/s72033-advipservicesk9_wan-mz.122-33.SXI12.bin"
Last reload reason: Reload Command

This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to
export@cisco.com.

cisco WS-C6506-E (R7000) processor (revision 1.2) with 983008K/65536K bytes of memory.
Processor board ID SAL1412DEVN
SR71000 CPU at 600Mhz, Implementation 0x504, Rev 1.2, 512KB L2 Cache
Last reset from s/w reset
32 Virtual Ethernet interfaces
99 Gigabit Ethernet interfaces
2 Ten Gigabit Ethernet interfaces
1917K bytes of non-volatile configuration memory.
8192K bytes of packet buffer memory.

65536K bytes of Flash internal SIMM (Sector size 512K).
Configuration register is 0x2102

the remote switch sh ver output is

TH_DC_core_01#show ver
Cisco IOS Software, s72033_rp Software (s72033_rp-ADVIPSERVICESK9_WAN-M), Version 12.2(33)SXI12, RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2013 by Cisco Systems, Inc.
Compiled Fri 30-Aug-13 16:07 by prod_rel_team

ROM: System Bootstrap, Version 12.2(17r)SX5, RELEASE SOFTWARE (fc1)

TH_DC_core_01 uptime is 15 weeks, 46 minutes
Uptime for this control processor is 15 weeks, 35 minutes
Time since TH_DC_core_01 switched to active is 15 weeks, 35 minutes
System returned to ROM by reload at 11:46:26 GMT Sun Nov 17 2013 (SP by reload)
System restarted at 11:49:27 GMT Sun Nov 17 2013
System image file is "sup-bootflash:s72033-advipservicesk9_wan-mz.122-33.SXI12.bin"
Last reload reason: Unknown reason

This product contains cryptographic features and is subject to United
States and local country laws governing import, export, transfer and
use. Delivery of Cisco cryptographic products does not imply
third-party authority to import, export, distribute or use encryption.
Importers, exporters, distributors and users are responsible for
compliance with U.S. and local country laws. By using this product you
agree to comply with applicable laws and regulations. If you are unable
to comply with U.S. and local laws, return this product immediately.

A summary of U.S. laws governing Cisco cryptographic products may be found at:
http://www.cisco.com/wwl/export/crypto/tool/stqrg.html

If you require further assistance please contact us by sending email to
export@cisco.com.

cisco WS-C6509-E (R7000) processor (revision 1.4) with 983008K/65536K bytes of memory.
Processor board ID SMC120300B3
SR71000 CPU at 600Mhz, Implementation 0x504, Rev 1.2, 512KB L2 Cache
Last reset from s/w reset
84 Virtual Ethernet interfaces
195 Gigabit Ethernet interfaces
10 Ten Gigabit Ethernet interfaces
1917K bytes of non-volatile configuration memory.
8192K bytes of packet buffer memory.

65536K bytes of Flash internal SIMM (Sector size 512K).
Configuration register is 0x2102

TH_DC_core_01#

The VLAN 10 clients that are not reachable from a remote network plug directly in to RU-core-1-6506

The outputs from the neighboring switch all look as expected...

TH_DC_core_02#show int gi5/2 trunk

Port                Mode         Encapsulation  Status        Native vlan
Gi5/2               on           802.1q         trunking      1

Port                Vlans allowed on trunk
Gi5/2               1,9-10,30-31,34,40,50,60,70,80,89-90,92,131-132,240,400-401,600-603,667,803,810,910-912,920-922,930

Port                Vlans allowed and active in management domain
Gi5/2               1,9-10,30-31,34,40,50,60,70,80,89-90,92,131-132,240,400-401,600-603,667,803,810,910-912,920-921,930

Port                Vlans in spanning tree forwarding state and not pruned
Gi5/2               1,9-10,30-31,34,40,50,60,70,80,89-90,92,131-132,240,400-401,600-603,667,803,810,910-912,920-921,930
TH_DC_core_02#

TH_DC_core_02#show int gi5/2 pruning

Port            Vlans pruned for lack of request by neighbor
Gi5/2           none

Port                Vlan traffic requested of neighbor
Gi5/2               1,9-10,30-31,34,40,50,60,70,80,89-90,92,131-132,240,400-401,600-603,667,803,810,910-912,920-921,930
TH_DC_core_02#

TH_DC_core_02#show run int gi5/2
Building configuration...

Current configuration : 442 bytes
!
interface GigabitEthernet5/2
description L2Trunk-Rushden
switchport
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,9,10,30,31,34,40,50,60,70,80,89,90,92,131,132
switchport trunk allowed vlan add 240,400,401,600-603,667,803,810,910-912
switchport trunk allowed vlan add 920-922,930
switchport trunk pruning vlan none
switchport mode trunk
mtu 9216
spanning-tree vlan 240,810 cost 2
spanning-tree cost 6
end

TH_DC_core_02#

TH_DC_core_02#show spann vlan 10

VLAN0010
  Spanning tree enabled protocol rstp
  Root ID    Priority    16394
             Address     001f.6d1a.a400
             Cost        1
             Port        1665 (Port-channel1)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    24586  (priority 24576 sys-id-ext 10)
             Address     001f.6d1a.9800
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 480

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/3               Desg FWD 19        128.3    P2p Edge
Gi1/4               Desg FWD 4         128.4    P2p Edge
Gi1/5               Desg FWD 4         128.5    P2p Edge
Gi1/6               Desg FWD 4         128.6    P2p Edge
Gi1/8               Desg FWD 19        128.8    P2p Edge
Gi1/11              Desg FWD 4         128.11   P2p Edge
Gi1/14              Desg FWD 4         128.14   P2p Edge

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------

Gi1/16              Desg FWD 4         128.16   P2p Edge
Gi1/19              Desg FWD 4         128.19   P2p Edge
Gi1/21              Desg FWD 4         128.21   P2p Edge
Gi1/22              Desg FWD 4         128.22   P2p Edge
Gi1/24              Desg FWD 4         128.24   P2p Edge
Gi1/28              Desg FWD 4         128.28   P2p Edge
Gi1/32              Desg FWD 4         128.32   P2p Edge
Gi1/34              Desg FWD 4         128.34   P2p Edge
Gi1/37              Desg FWD 4         128.37   P2p Edge
Gi1/39              Desg FWD 4         128.39   P2p Edge
Gi1/40              Desg FWD 4         128.40   P2p Edge
Gi1/42              Desg FWD 4         128.42   P2p Edge
Gi1/43              Desg FWD 4         128.43   P2p Edge
Gi1/44              Desg FWD 19        128.44   P2p Edge
Gi1/45              Desg FWD 4         128.45   P2p Edge
Gi1/46              Desg FWD 4         128.46   P2p Edge
Gi2/10              Desg FWD 19        128.138  P2p Edge
Gi2/11              Desg FWD 4         128.139  P2p Edge
Gi2/12              Desg FWD 4         128.140  P2p Edge
Gi2/14              Desg FWD 4         128.142  P2p Edge
Gi2/16              Desg FWD 4         128.144  P2p Edge
Gi2/17              Desg FWD 4         128.145  P2p Edge
Gi2/18              Desg FWD 4         128.146  P2p Edge

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------

Gi2/20              Desg FWD 4         128.148  P2p Edge
Gi2/21              Desg FWD 4         128.149  P2p Edge
Gi2/22              Desg FWD 4         128.150  P2p Edge
Gi2/23              Desg FWD 4         128.151  P2p Edge
Gi2/25              Desg FWD 4         128.153  P2p Edge
Gi2/28              Desg FWD 4         128.156  P2p Edge
Gi2/33              Desg FWD 4         128.161  P2p Edge
Gi2/37              Desg FWD 4         128.165  P2p Edge
Gi2/38              Desg FWD 4         128.166  P2p Edge
Gi2/39              Desg FWD 4         128.167  P2p Edge
Gi2/40              Desg FWD 19        128.168  P2p Edge
Gi2/41              Desg FWD 19        128.169  P2p Edge
Gi3/4               Desg FWD 4         128.260  P2p Edge
Gi3/7               Desg FWD 4         128.263  P2p Edge
Gi3/8               Desg FWD 4         128.264  P2p Edge
Gi3/9               Desg FWD 4         128.265  P2p Edge
Gi3/11              Desg FWD 4         128.267  P2p Edge
Gi3/14              Desg FWD 4         128.270  P2p Edge
Gi3/15              Desg FWD 4         128.271  P2p Edge
Gi3/17              Desg FWD 4         128.273  P2p Edge
Gi3/20              Desg FWD 4         128.276  P2p Edge
Gi3/21              Desg FWD 4         128.277  P2p Edge
Gi3/25              Desg FWD 19        128.281  P2p Edge

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------

Gi3/28              Desg FWD 4         128.284  P2p Edge
Gi3/29              Desg FWD 4         128.285  P2p Edge
Gi3/33              Desg FWD 4         128.289  P2p Edge
Gi3/35              Desg FWD 4         128.291  P2p Edge
Gi3/36              Desg FWD 4         128.292  P2p Edge
Gi3/38              Desg FWD 4         128.294  P2p Edge
Gi3/41              Desg FWD 4         128.297  P2p Edge
Gi3/42              Desg FWD 4         128.298  P2p Edge
Gi3/43              Desg FWD 4         128.299  P2p Edge
Gi3/44              Desg FWD 4         128.300  P2p Edge
Gi3/45              Desg FWD 4         128.301  P2p Edge
Gi5/2               Desg FWD 6         128.514  P2p
Gi8/1               Desg FWD 4         128.897  P2p Edge
Gi8/2               Desg FWD 4         128.898  P2p Edge
Gi8/10              Desg FWD 4         128.906  P2p Edge
Gi8/11              Desg FWD 4         128.907  P2p Edge
Gi8/13              Desg FWD 4         128.909  P2p Edge
Gi8/14              Desg FWD 4         128.910  P2p Edge
Gi8/16              Desg FWD 4         128.912  P2p Edge
Gi8/17              Desg FWD 4         128.913  P2p Edge
Gi8/18              Desg FWD 4         128.914  P2p Edge
Gi8/19              Desg FWD 4         128.915  P2p Edge
Gi8/20              Desg FWD 4         128.916  P2p Edge

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------

Gi8/22              Desg FWD 4         128.918  P2p Edge
Gi8/23              Desg FWD 4         128.919  P2p Edge
Gi8/40              Desg FWD 4         128.936  P2p Edge
Gi8/44              Desg FWD 4         128.940  P2p Edge
Po1                 Root FWD 1         128.1665 P2p
Po20                Desg FWD 3         128.1669 P2p

TH_DC_core_02#

[marioderosa2008]

to give you some background information too...

the 1gig link is a point to point DC link...

we installed a new 10gig link (terminating on different switches)

spanning tree then used the 10gig link as the best path to the root bridge as expected...

we were experiencing some problems with some systems since we moved the vlans on to the 10gig link so we simply reversed the change and put vlans back on to 1gig link...

since then, the switch is pruning vlans mistakenly.

These vlans have been working fine on this 1gig link for years...

only since introduction of 10gig link has this started to become an issue.

we are planning to remove the 1gig link completely, but we have to roll back to see if this clears the system issues we've been seeing since making the change.

[marioderosa2008]

                   attached is a pdf showing the current topology....

[marioderosa2008]

This is now resolved by rebooting the chassis.

Removing pruning, or switching from client to transparent and back did not resolve the issue.

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