Hello Pros
I had a problem on a number of switches recently for an hour, and I'm trying to findout why. I've never seen this error before, and our network has never had a Loop, but for some reason whether is was the design or a software or hardware problem we had one. We have a number of 3750 switch stacks that connect together, some connect with Port-Channels, some just have a single connection, but all seems to have this problem at the same time.
If you look at the diagram attached, which is a cut down version, each switch stack connects to Switch Stack 2 on a single VLAN only, but Switch Stack 2 and 3 reported a problem on all VLANs that are Trunked accross the link. The primary connection between Switch Stack2 and 3 is a 1Gb Fiber, and the Secondary connection is 100Mb Wireless. All the traffic goes across the Fiber as I have a ST cost of 100 on the Wireless
I'd just like to know the following if possible.
1. Could the design be part of the problem and how can I keep the connectivity to my second data center loop free.
2. Could it be a software related, all switch stacks are running IOS 3750-ipservicesk9-mz.122-53.SE1.bin
3. If there was a problem some where on the Fiber that my ISP isn't letting me know, could this have caused the problem.
See some more info below, and again I've attached a network diagram.
Thanks
! Switch Stack 1
!
interface Port-channel1
switchport access vlan 10
switchport mode access
speed 100
duplex full
!
interface FastEthernet2/0/45
switchport access vlan 10
switchport mode access
speed 100
duplex full
channel-group 1 mode on
!
interface FastEthernet3/0/45
switchport access vlan 10
switchport mode access
speed 100
duplex full
channel-group 1 mode on
!
#sho spanning-tree vlan 10
VLAN0010
Spanning tree enabled protocol ieee
Root ID Priority 32860
Address 000f.f7a9.c680
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32860 (priority 32768 sys-id-ext 92)
Address 000f.f7a9.c680
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Po1 Desg FWD 12 128.504 P2p
Po2 Desg FWD 12 128.512 P2p
Po3 Desg FWD 12 128.520 P2p
Po4 Desg FWD 19 128.496 P2p
!
! Switch Stack 2
!
interface Port-channel1
switchport access vlan 10
switchport mode access
speed 100
duplex full
!
interface GigabitEthernet1/0/6
switchport access vlan 10
switchport mode access
speed 100
duplex full
channel-group 1 mode on
!
interface GigabitEthernet2/0/6
switchport access vlan 10
switchport mode access
speed 100
duplex full
channel-group 1 mode on
!
interface GigabitEthernet1/0/1
description Trunk to Data Center 2 (Via Fiber)
switchport trunk encapsulation dot1q
switchport mode trunk
speed 1000
duplex full
!
interface GigabitEthernet2/0/1
description Trunk to Data center 2 over 100Mb Wireless
switchport trunk encapsulation dot1q
switchport mode trunk
speed 100
duplex full
spanning-tree vlan 1,10-13 cost 100
!
!
!
#sho spanning-tree vlan 10
VLAN0010
Spanning tree enabled protocol ieee
Root ID Priority 32860
Address 000f.f7a9.c680
Cost 12
Port 520 (Port-channel5)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Bridge ID Priority 32860 (priority 32768 sys-id-ext 92)
Address 6416.8d15.5980
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1 Desg FWD 4 128.1 P2p
Po1 Root FWD 12 128.520 P2p
Gi2/0/1 Desg FWD 100 128.55 P2p
