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New Member

spanning tree loop?

I get these logs on a 4506 supIV I know that usually that indicates a loop. as far as i know there arent any physical loops. and if there was would i get tons of these logs and not just one every few hours or so.

Thanks in advance

Sep 10 02:59:03: %C4K_EBM-4-HOSTFLAPPING: Host 00:03:47:35:E9:4D in vlan 1 is fl

apping between port Gi2/5 and port Gi3/3

Sep 10 06:26:29: %C4K_EBM-4-HOSTFLAPPING: Host 00:01:03:BE:94:B0 in vlan 1 is fl

apping between port Gi2/5 and port Gi3/3

Sep 10 06:47:58: %C4K_EBM-4-HOSTFLAPPING: Host 00:90:27:77:C2:8F in vlan 1 is fl

apping between port Gi2/5 and port Fa4/3

Sep 10 07:06:54: %C4K_EBM-4-HOSTFLAPPING: Host 00:C0:9F:05:6D:70 in vlan 1 is fl

apping between port Gi2/5 and port Po2

Sep 10 17:09:58: %C4K_EBM-4-HOSTFLAPPING: Host 00:00:79:50:23:FF in vlan 1 is fl

apping between port Gi2/5 and port Po1

Sep 10 18:01:40: %C4K_EBM-4-HOSTFLAPPING: Host 00:01:03:BE:94:B0 in vlan 1 is fl

apping between port Gi2/5 and port Gi3/3

Sep 10 18:02:39: %C4K_EBM-4-HOSTFLAPPING: Host 00:50:DA:65:08:41 in vlan 1 is fl

apping between port Gi2/5 and port Fa4/3

Sep 10 19:57:37: %C4K_EBM-4-HOSTFLAPPING: Host 00:03:47:BF:91:21 in vlan 1 is fl

apping between port Gi2/5 and port Gi2/3

Sep 10 22:25:33: %C4K_EBM-4-HOSTFLAPPING: Host 00:08:74:1F:C1:26 in vlan 1 is fl

apping between port Gi2/5 and port Fa5/32

2 REPLIES
New Member

Re: spanning tree loop?

So you have STP set up properly?????

I know spanning tree is on by default in new switches.. But if you turned it off it would forward out of all available ports and create loops....

New Member

Re: spanning tree loop?

I think its right

from a Sh run

ip subnet-zero

no ip domain-lookup

!

!

spanning-tree extend system-id

spanning-tree vlan 1-5 priority 24576

!

!

4506#sh spanning-tree

VLAN0001

Spanning tree enabled protocol ieee

Root ID Priority 24577

Address 000b.5f78.ee00

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 000b.5f78.ee00

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

Aging Time 300

Interface Role Sts Cost Prio.Nbr Type

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

Gi1/1 Desg FWD 4 128.1 P2p

Gi1/2 Desg FWD 4 128.2 P2p

Gi2/3 Desg FWD 4 128.67 P2p

Gi2/4 Desg FWD 4 128.68 P2p

Gi2/5 Desg FWD 4 128.69 P2p

Gi3/3 Desg FWD 4 128.131 P2p

Gi3/4 Desg FWD 4 128.132 P2p

Fa4/2 Desg FWD 19 128.194 P2p

Fa4/3 Desg FWD 19 128.195 P2p

Interface Role Sts Cost Prio.Nbr Type

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

Fa4/5 Desg FWD 19 128.197 P2p

Fa4/34 Desg FWD 19 128.226 P2p

Fa4/35 Desg FWD 19 128.227 P2p

Fa5/38 Desg FWD 19 128.294 P2p

Po1 Desg FWD 3 128.449 P2p

Po2 Desg FWD 3 128.450 P2p

VLAN0002

Spanning tree enabled protocol ieee

Root ID Priority 24578

Address 000b.5f78.ee00

This bridge is the root

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

Bridge ID Priority 24578 (priority 24576 sys-id-ext 2)

Address 000b.5f78.ee00

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

Aging Time 300

Interface Role Sts Cost Prio.Nbr Type

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

Gi1/1 Desg FWD 4 128.1 P2p

Gi1/2 Desg FWD 4 128.2 P2p

Gi2/3 Desg FWD 4 128.67 P2p

Gi2/4 Desg FWD 4 128.68 P2p

Gi2/5 Desg FWD 4 128.69 P2p

Gi3/3 Desg FWD 4 128.131 P2p

Gi3/4 Desg FWD 4 128.132 P2p

Fa4/3 Desg FWD 19 128.195 P2p

Po2 Desg FWD 3 128.450 P2p

on another switch

2950-48#sh spanning-tree

VLAN0001

Spanning tree enabled protocol ieee

Root ID Priority 24577

Address 000b.5f78.ee00

Cost 4

Port 49 (GigabitEthernet0/1)

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

Bridge ID Priority 32769 (priority 32768 sys-id-ext 1)

Address 000b.5f21.cbc0

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

Aging Time 300

Interface Port ID Designated Port ID

Name Prio.Nbr Cost Sts Cost Bridge ID Prio.Nbr

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

Fa0/26 128.26 19 FWD 4 32769 000b.5f21.cbc0 128.26

Gi0/1 128.49 4 FWD 0 24577 000b.5f78.ee00 128.2

VLAN0002

Spanning tree enabled protocol ieee

Root ID Priority 24578

Address 000b.5f78.ee00

Cost 4

Port 49 (GigabitEthernet0/1)

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

Bridge ID Priority 32770 (priority 32768 sys-id-ext 2)

Address 000b.5f21.cbc0

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

Aging Time 300

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