switch based fiber ring

Unanswered Question
Aug 11th, 2008

I have a fiber ring using 1 3548xl, 2 3512xl, a 3508, and the gbic card for a 6509. One link in the loop is "state changed to up" for a few seconds, then down again, and repeats. Is this normal for a loop in this configuration?

I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Loading.
rais Mon, 08/11/2008 - 06:46

Apparently the network is not stable.

Are you using UDLD? Is your STP converging again and again too? Do you see another interface bouncing as well?

Thanks.

smcghelpdesk Mon, 08/11/2008 - 07:07

I've posted my "sh udld" from the switch that is showing:

Interface Gi0/1

Port enable configuration setting: Follows global setting

Operational enable state: Disabled

Current bidirectional state: Unknown

Message interval: 7

Message timer: 1

Current operational state: Disabled and link down

Time out interval: 5

Time out timer: 0

Restart counter: 0

Neighbors counter: 0

Probe counter: 4

No multiple neighbors detected

Current pool id: 1

No neighbor cache information stored

Also, I'm not showing any of the other interfaces on the loop doing the "UP/Down" bounce.

Another note: This was working. About a year ago our fiber was cut, and the loop held. Could this be caused by bad GBICs? I've tested the fiber, it shows good.

I'm guessing by your post that I should see this link active all the time. Is that correct?

Thanks for looking into this with me.

cowetacoit Mon, 08/11/2008 - 07:09

post a show interface gx/x for the switch that is bouncing, post a show spanning-tree as well

smcghelpdesk Mon, 08/11/2008 - 07:20

I'm posting the sh int g0/1 twice, just to show the state of things in both the up and down states.

Thanks.

CarterBldg#sh int g0/1

GigabitEthernet0/1 is down, line protocol is down

Hardware is Gigabit Ethernet, address is 0002.4b10.b3cd (bia 0002.4b10.b3cd)

MTU 1500 bytes, BW 0 Kbit, DLY 0 usec,

reliability 255/255, txload 255/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive not set

Auto-duplex , link type is autonegotiation, media type is SX

output flow-control is off, input flow-control is off

ARP type: ARPA, ARP Timeout 04:00:00

Last input never, output 00:00:03, output hang never

Last clearing of "show interface" counters never

Queueing strategy: fifo

Output queue 0/40, 0 drops; input queue 0/75, 0 drops

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 7000 bits/sec, 7 packets/sec

1 packets input, 64 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 0 multicast, 0 pause input

1850656 packets output, 206806141 bytes, 0 underruns

0 output errors, 0 collisions, 1 interface resets

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

CarterBldg#

CarterBldg#sh int g0/1

GigabitEthernet0/1 is up, line protocol is up

Hardware is Gigabit Ethernet, address is 0002.4b10.b3cd (bia 0002.4b10.b3cd)

MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

reliability 255/255, txload 255/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive not set

Auto-duplex (Full), link type is autonegotiation, media type is SX

output flow-control is off, input flow-control is off

ARP type: ARPA, ARP Timeout 04:00:00

Last input never, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Queueing strategy: fifo

Output queue 0/40, 0 drops; input queue 0/75, 0 drops

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 8000 bits/sec, 6 packets/sec

1 packets input, 64 bytes, 0 no buffer

Received 0 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 0 multicast, 0 pause input

1850709 packets output, 206814485 bytes, 0 underruns

0 output errors, 0 collisions, 1 interface resets

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

CarterBldg#sh spanning-tree

Spanning tree 1 is executing the IEEE compatible Spanning Tree protocol

Bridge Identifier has priority 32768, address 0002.4b10.b3c0

Configured hello time 2, max age 20, forward delay 15

Current root has priority 5, address 00d0.021f.ac00

Root port is 39, cost of root path is 3016

Topology change flag not set, detected flag not set, changes 2

Times: hold 1, topology change 35, notification 2

hello 2, max age 20, forward delay 15

Timers: hello 0, topology change 0, notification 0

Interface Gi0/1 (port 31) in Spanning tree 1 is down

Port path cost 4, Port priority 128

Designated root has priority 5, address 00d0.021f.ac00

Designated bridge has priority 32768, address 0002.4b10.b3c0

Designated port is 31, path cost 3016

Timers: message age 0, forward delay 0, hold 0

BPDU: sent 31408, received 0

Interface Gi0/2 (port 39) in Spanning tree 1 is FORWARDING

Port path cost 4, Port priority 128

Designated root has priority 5, address 00d0.021f.ac00

Designated bridge has priority 32768, address 0009.e8e1.f5c0

Designated port is 23, path cost 3012

Timers: message age 0, forward delay 0, hold 0

BPDU: sent 1, received 126197

cowetacoit Mon, 08/11/2008 - 07:29

find your root bridge, it's mac is 00d0.021f.ac00. check its log and look at the show spanning-tree outputs.

smcghelpdesk Mon, 08/11/2008 - 07:57

I've attached the sh spanning-tree info because it's quite a bit different than what I get on the other switches...

VLAN0001 is associated with that mac, although we usually disable that vlan on our network. The fast ethernet ports are on vlan0004 and the administrative network is vlan0202.

The logs for that switch show nothing about the fiber ports, only various fastethers connecting and disconnecting.

Any ideas? Thanks again.

VLAN0001

Spanning tree enabled protocol ieee

Root ID Priority 5

Address 00d0.021f.ac00

Cost 3004

Port 49 (GigabitEthernet0/1)

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

Bridge ID Priority 49153 (priority 49152 sys-id-ext 1)

Address 0015.f974.5180

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

Aging Time 300

Uplinkfast enabled

Interface Role Sts Cost Prio.Nbr Type

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

Gi0/1 Root FWD 3004 128.49 P2p

Gi0/2 Desg FWD 3004 128.50 P2p

VLAN0004

Spanning tree enabled protocol ieee

Root ID Priority 32768

Address 0002.4b10.b3c3

Cost 3012

Port 50 (GigabitEthernet0/2)

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

Bridge ID Priority 49156 (priority 49152 sys-id-ext 4)

Address 0015.f974.5180

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

Aging Time 300

Uplinkfast enabled

Interface Role Sts Cost Prio.Nbr Type

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

Gi0/1 Desg FWD 3004 128.49 P2p

Gi0/2 Root FWD 3004 128.50 P2p

Actions

This Discussion