[c-nsp] STP active/listed on wrong port

[Chuck Church]

You're using 802.1q, which uses an untagged native VLAN for things like STP
BPDUs, CDP, VTP, etc ,etc.  Even though you pruned off VLAN 1 via the
allowed VLANs command, the native VLAN will still be used for
switch-generated protocols like those listed above.  Only transit-traffic is
denied by pruning.  If you change the native VLAN to something other than
one (do it on both sides, or wacky/painful things can happen), you should
see VLAN 1 no longer on that port.

Chuck

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of "Rolf Hanßen"
Sent: Tuesday, March 12, 2013 1:34 PM
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] STP active/listed on wrong port

Hello list,

do you have an explanation why STP thinks Gi7/16 belongs to vlan 1 ?

edge1-dus3#sh spanning-tree

VLAN0001
  Spanning tree enabled protocol ieee
  Root ID    Priority    32769
             Address     5475.d0a6.75c0
             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     5475.d0a6.75c0
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 300

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- --------
--------------------------------
Gi7/16              Desg FWD 4         128.1552 P2p


Interface Config:
interface GigabitEthernet7/16
 description custsw2-dus1 A16
 switchport
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 1253,1606  switchport mode trunk  mtu 9216
load-interval 30 end

STP is disabled on all other vlans:
no spanning-tree vlan 2-4000

Gi7/16 is not listed here:

edge1-dus3#sh vlan id 1

VLAN Name                             Status    Ports
---- -------------------------------- ---------
-------------------------------
1    default                          active    Gi1/5, Gi1/8, Gi1/13,
Gi1/25, Gi1/27, Gi1/48, Te4/1, Gi6/1, Gi7/1, Gi7/3, Gi7/4, Gi7/5, Gi7/6,
Gi7/7, Gi7/8, Gi7/9, Gi7/10, Gi7/11, Gi7/12, Gi7/13, Gi7/14, Gi7/15, Gi7/17,
Gi7/18, Gi7/19
                                                Gi7/20, Gi7/21, Gi7/22,
Gi7/23, Gi7/24

VLAN Type  SAID       MTU   Parent RingNo BridgeNo Stp  BrdgMode Trans1
Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------
------
1    enet  100001     1500  -      -      -        -    -        0      0

Remote SPAN VLAN
----------------
Disabled

Primary Secondary Type              Ports
------- --------- -----------------
------------------------------------------


Port is up and works fine:

edge1-dus3#sh int Gi7/16
GigabitEthernet7/16 is up, line protocol is up (connected)
  Hardware is C6k 1000Mb 802.3, address is 001d.a246.3743 (bia
001d.a246.3743)
  Description: custsw2-dus1 A16
  MTU 9216 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
     reliability 255/255, txload 6/255, rxload 6/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is LX
  input flow-control is off, output flow-control is off
  Clock mode is auto
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output never, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  30 second input rate 27117000 bits/sec, 3517 packets/sec
  30 second output rate 24383000 bits/sec, 2860 packets/sec
     32078138057 packets input, 32998390284372 bytes, 0 no buffer
     Received 524965 broadcasts (173874 multicasts)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 0 multicast, 0 pause input
     0 input packets with dribble condition detected
     13839785752 packets output, 9991981200426 bytes, 0 underruns
     0 output errors, 0 collisions, 3 interface resets
     0 unknown protocol drops
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 pause output
     0 output buffer failures, 0 output buffers swapped out


edge1-dus3#sh version
Cisco IOS Software, c7600s72033_rp Software
(c7600s72033_rp-ADVIPSERVICESK9-M), Version 15.1(2)S, RELEASE SOFTWARE
(fc1)

Hardware is Cisco 7609-S, Sub720-3BXL, Slot 7 is a WS-X6724-SFP

kind regards
Rolf Hanßen



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