From: ahmet seckin (elektronikadam@yahoo.com)
Date: Tue May 20 2008 - 14:37:00 ART
Dear all,
I have a lab with the following connections. Basically I tried to do l2protocol tunneling between SW3 and SW4. Dot1Q tunnel works fine, but when I turned on the l2protocol tunnelling, the link between SW1 and SW2 starts flapping. SW1 and SW2 starts getting TCNs and root of the spanning tree changes again and again. I have copied the SW1 output below. The configuratioin of SW2 is the same as SW1.
SW3(2950)-fa0/1------------g0/1--SW1(3560)--g0/3-------------g0/3--SW2(3560)-g0/1---------SW4(2950)
Any idea would be much appreciated.
Regards
Ahmet
------------------------------------------------
SW1#
SW1#
SW1#sh span
VLAN0001
Spanning tree enabled protocol ieee
Root ID Priority 24577
Address 0019.3029.e600
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 24577 (priority 24576 sys-id-ext 1)
Address 0019.3029.e600
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
--More--
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/3 Desg FWD 4 128.3 P2p
--More--
VLAN0055
Spanning tree enabled protocol ieee
Root ID Priority 24631
Address 0019.3029.e600
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 24631 (priority 24576 sys-id-ext 55)
Address 0019.3029.e600
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300
--More--
Interface Role Sts Cost Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/3 Desg FWD 4 128.3 P2p
SW1#
SW1#
SW1#
SW1#sh int trun
Port Mode Encapsulation Status Native vlan
Gi0/3 on 802.1q trunking 1
Port Vlans allowed on trunk
Gi0/3 1-4094
Port Vlans allowed and active in management domain
Gi0/3 1,55
Port Vlans in spanning tree forwarding state and not pruned
Gi0/3 1,55
SW1#sh vlan
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Gi0/2, Gi0/4, Gi0/5, Gi0/6
Gi0/7, Gi0/8, Gi0/9, Gi0/10
Gi0/11, Gi0/12, Gi0/13, Gi0/14
Gi0/15, Gi0/16, Gi0/17, Gi0/18
Gi0/19, Gi0/20, Gi0/21, Gi0/22
Gi0/23, Gi0/24, Gi0/25, Gi0/26
Gi0/27, Gi0/28, Gi0/29, Gi0/30
Gi0/31, Gi0/32, Gi0/33, Gi0/34
Gi0/35, Gi0/36, Gi0/37, Gi0/38
--More--
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
Gi0/39, Gi0/40, Gi0/41, Gi0/42
Gi0/43, Gi0/44, Gi0/45, Gi0/46
Gi0/47, Gi0/48, Gi0/49, Gi0/50
Gi0/51, Gi0/52
55 VLAN0055 active Gi0/1
1002 fddi-default act/unsup
1003 token-ring-default act/unsup
1004 fddinet-default act/unsup
1005 trnet-default act/unsup
VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
--More--
VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
---- ----- ---------- ----- ------ ------ -------- ---- -------- ------ ------
1 enet 100001 1500 - - - - - 0 0
55 enet 100055 1500 - - - - - 0 0
1002 fddi 101002 1500 - - - - - 0 0
1003 tr 101003 1500 - - - - srb 0 0
1004 fdnet 101004 1500 - - - ieee - 0 0
1005 trnet 101005 1500 - - - ibm - 0 0
Remote SPAN VLANs
------------------------------------------------------------------------------
Primary Secondary Type Ports
------- --------- ----------------- ------------------------------------------
SW1#
SW1#
SW1#sh int g0/1 swit
Name: Gi0/1
Switchport: Enabled
Administrative Mode: tunnel
Operational Mode: down
Administrative Trunking Encapsulation: negotiate
Negotiation of Trunking: Off
Access Mode VLAN: 55 (VLAN0055)
Trunking Native Mode VLAN: 1 (default)
Administrative Native VLAN tagging: enabled
Voice VLAN: none
Administrative private-vlan host-association: none
Administrative private-vlan mapping: none
--More-- Administrative private-vlan trunk native VLAN: none
Administrative private-vlan trunk Native VLAN tagging: enabled
Administrative private-vlan trunk encapsulation: dot1q
Administrative private-vlan trunk normal VLANs: none
Administrative private-vlan trunk private VLANs: none
Operational private-vlan: none
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled: 2-1001
Capture Mode Disabled
Capture VLANs Allowed: ALL
Protected: false
--More-- Unknown unicast blocked: disabled
Unknown multicast blocked: disabled
Appliance trust: none
SW1#sh system mtu
System MTU size is 1504 bytes
System Jumbo MTU size is 1504 bytes
Routing MTU size is 1504 bytes
SW1#
SW1#
SW1#
SW1#sh run int g0/1
Building configuration...
Current configuration : 118 bytes
!
interface GigabitEthernet0/1
switchport access vlan 55
switchport mode dot1q-tunnel
shutdown
no cdp enable
end
SW1#sh run int g0/3
Building configuration...
Current configuration : 97 bytes
!
interface GigabitEthernet0/3
switchport trunk encapsulation dot1q
switchport mode trunk
end
SW1#
SW1#
SW1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
SW1(config)#int g0/1
SW1(config-if)#l2p cdp
SW1(config-if)#no l2p cdp
SW1(config-if)#no sh
SW1(config-if)#
04:13:01: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to down
SW1(config-if)#
04:13:04: %LINK-3-UPDOWN: Interface GigabitEthernet0/1, changed state to up
04:13:05: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/1, changed state to up
SW1(config-if)#
SW1(config-if)#
SW1(config-if)#do sh clock
*04:14:34.966 UTC Mon Mar 1 1993
SW1(config-if)#l2proto cdp
SW1(config-if)#do sh l2p
COS for Encapsulated Packets: 5
Drop Threshold for Encapsulated Packets: 0
Port Protocol Shutdown Drop Encapsulation Decapsulation Drop
Threshold Threshold Counter Counter Counter
---------- -------- --------- --------- ------------- ------------- -------------
Gi0/1 cdp ---- ---- 0 0 0
--- ---- ---- ---- ---- ----
--- ---- ---- ---- ---- ----
--More-- --- ---- ---- ---- ---- ----
--- ---- ---- ---- ---- ----
--- ---- ---- ---- ---- ----
SW1(config-if)#do sh l2p
COS for Encapsulated Packets: 5
Drop Threshold for Encapsulated Packets: 0
Port Protocol Shutdown Drop Encapsulation Decapsulation Drop
Threshold Threshold Counter Counter Counter
---------- -------- --------- --------- ------------- ------------- -------------
Gi0/1 cdp ---- ---- 0 0 0
--- ---- ---- ---- ---- ----
--- ---- ---- ---- ---- ----
--More-- --- ---- ---- ---- ---- ----
--- ---- ---- ---- ---- ----
--- ---- ---- ---- ---- ----
SW1(config-if)# do sh l2p
COS for Encapsulated Packets: 5
Drop Threshold for Encapsulated Packets: 0
Port Protocol Shutdown Drop Encapsulation Decapsulation Drop
Threshold Threshold Counter Counter Counter
---------- -------- --------- --------- ------------- ------------- -------------
Gi0/1 cdp ---- ---- 0 0 0
--- ---- ---- ---- ---- ----
--- ---- ---- ---- ---- ----
--More-- --- ---- ---- ---- ---- ----
--- ---- ---- ---- ---- ----
--- ---- ---- ---- ---- ----
SW1(config-if)#
04:18:12: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/3, changed state to down
04:18:12: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
SW1(config-if)#
04:18:13: %LINK-3-UPDOWN: Interface GigabitEthernet0/3, changed state to down
SW1(config-if)#
SW1(config-if)#
SW1(config-if)#
SW1(config-if)#
SW1(config-if)#
SW1(config-if)#
SW1(config-if)#do sh l2p
COS for Encapsulated Packets: 5
Drop Threshold for Encapsulated Packets: 0
Port Protocol Shutdown Drop Encapsulation Decapsulation Drop
Threshold Threshold Counter Counter Counter
---------- -------- --------- --------- ------------- ------------- -------------
Gi0/1 cdp ---- ---- 1 0 0
--- ---- ---- ---- ---- ----
--- ---- ---- ---- ---- ----
--More-- --- ---- ---- ---- ---- ----
--- ---- ---- ---- ---- ----
--- ---- ---- ---- ---- ----
SW1(config-if)#
04:18:46: %LINK-3-UPDOWN: Interface GigabitEthernet0/3, changed state to up
SW1(config-if)#
04:18:47: setting bridge id (which=3) prio 24577 prio cfg 24576 sysid 1 (on) id 6001.0019.3029.e600
04:18:47: set portid: VLAN0001 Gi0/3: new port id 8003
04:18:47: STP: VLAN0001 Gi0/3 -> listening
04:18:47: set portid: VLAN0055 Gi0/3: new port id 8003
04:18:47: STP: VLAN0055 Gi0/3 -> listening
04:18:48: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/3, changed state to up
SW1(config-if)#
04:18:54: STP: VLAN0001 heard root 28673-0019.3073.1880 on Gi0/3
04:18:54: STP: VLAN0055 heard root 28727-0019.3073.1880 on Gi0/3
04:18:54: STP: VLAN0001 Topology Change rcvd on Gi0/3
04:18:54: STP: VLAN0055 Topology Change rcvd on Gi0/3
SW1(config-if)#
04:19:02: STP: VLAN0001 Gi0/3 -> learning
04:19:02: STP: VLAN0055 Gi0/3 -> learning
SW1(config-if)#
04:19:17: STP: VLAN0001 Gi0/3 -> forwarding
04:19:17: STP: VLAN0055 Gi0/3 -> forwarding
04:19:18: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to up
SW1(config-if)#
SW1(config-if)#
SW1(config-if)#
SW1(config-if)#
SW1(config-if)#do sh debug
Spanning Tree:
Spanning Tree event debugging is on
Spanning Tree root changes debugging is on
Condition 1: interface Gi0/3 (1 flags triggered)
Flags: Gi0/3
SW1(config-if)#
SW1(config-if)#
04:20:12: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/3, changed state to down
04:20:12: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to down
SW1(config-if)#
04:20:13: %LINK-3-UPDOWN: Interface GigabitEthernet0/3, changed state to down
SW1(config-if)#
04:20:16: %LINK-3-UPDOWN: Interface GigabitEthernet0/3, changed state to up
SW1(config-if)#
04:20:17: setting bridge id (which=3) prio 24577 prio cfg 24576 sysid 1 (on) id 6001.0019.3029.e600
04:20:17: set portid: VLAN0001 Gi0/3: new port id 8003
04:20:17: STP: VLAN0001 Gi0/3 -> listening
04:20:17: set portid: VLAN0055 Gi0/3: new port id 8003
04:20:17: STP: VLAN0055 Gi0/3 -> listening
SW1(config-if)#
04:20:18: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet0/3, changed state to up
SW1(config-if)#
SW1(config-if)#
SW1(config-if)#
SW1(config-if)#
SW1(config-if)#
SW1(config-if)#
SW1(config-if)#do unde al
All possible debugging has been turned off
SW1(config-if)#do sh ver
Cisco IOS Software, C3560 Software (C3560-IPBASE-M), Version 12.2(25)SEE2, RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2006 by Cisco Systems, Inc.
Compiled Fri 28-Jul-06 07:19 by yenanh
Image text-base: 0x00003000, data-base: 0x00EB0F14
ROM: Bootstrap program is C3560 boot loader
BOOTLDR: C3560 Boot Loader (C3560-HBOOT-M) Version 12.2(25r)SEE4, RELEASE SOFTWARE (fc1)
SW1 uptime is 4 hours, 20 minutes
System returned to ROM by power-on
--More-- System image file is "flash:/c3560-ipbase-mz.122-25.SEE2/c3560-ipbase-mz.122-25.SEE2.bin"
cisco WS-C3560G-48TS (PowerPC405) processor (revision D0) with 118784K/12280K bytes of memory.
Processor board ID FOC1101Y0KY
Last reset from power-on
1 Virtual Ethernet interface
52 Gigabit Ethernet interfaces
The password-recovery mechanism is enabled.
512K bytes of flash-simulated non-volatile configuration memory.
--More-- Base ethernet MAC Address : 00:19:30:29:E6:00
Motherboard assembly number : 73-10214-04
Power supply part number : 341-0107-01
Motherboard serial number : FOC11010TM9
Power supply serial number : FXD102000BQ
Model revision number : D0
Motherboard revision number : B0
Model number : WS-C3560G-48TS-S
System serial number : FOC1101Y0KY
Top Assembly Part Number : 800-26849-01
Top Assembly Revision Number : A0
Version ID : V03
--More-- CLEI Code Number : CNMWY00ARC
Hardware Board Revision Number : 0x09
Switch Ports Model SW Version SW Image
------ ----- ----- ---------- ----------
* 1 52 WS-C3560G-48TS 12.2(25)SEE2 C3560-IPBASE-M
Configuration register is 0xF
SW1(config-if)#
04:20:48: %LINEPROTO-5-UPDOWN: Line protocol on Interface Vlan1, changed state to up
SW1(config-if)#
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