Multimode fiber loop

[m.alshaweesh@extensya.com]

Hi all,

i have Cisco core 4507 with Ten GB interface , i want to connect this interface with Multi mode fiber connection to an edge switch that have 1GB interface , both interface are up but there is no connectivity  between two switches , when execute  the show spanning tree the results

shows that the port are is BLK state:

sh spanning-tree vlan 205

VLAN0205
Spanning tree enabled protocol rstp
Root ID Priority 32973
Address 5897.1e07.2680
Cost 19
Port 10 (GigabitEthernet1/10)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32973 (priority 32768 sys-id-ext 205)
Address 70db.987c.ba80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Te3/1 Back BLK 4 128.257 P2p

[chrihussey]

Can you post the interface configs and the interface status for both?

Thanks

[m.alshaweesh@extensya.com]

Ext-Amm-Core#show running-config interface tenGigabitEthernet 3/1
Building configuration...

Current configuration : 107 bytes
!
interface TenGigabitEthernet3/1
switchport trunk allowed vlan 205
switchport mode trunk
end

Ext-Amm-Core#show interfaces tenGigabitEthernet 3/1
TenGigabitEthernet3/1 is administratively down, line protocol is down (disabled)
Hardware is Ten Gigabit Ethernet Port, address is 70db.987c.ba80 (bia 70db.987c.ba80)
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, Auto-speed, link type is auto, media type is 1000BaseSX
input flow-control is off, output flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input 00:42:35, 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)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
831 packets input, 203230 bytes, 0 no buffer
Received 829 broadcasts (829 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
831 packets output, 203230 bytes, 0 underruns
0 output errors, 0 collisions, 7 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out

[chrihussey]

The interface is shutdown, it needs to be enabled.

int te3/1

no shut

If that doesn't work, can you post the output of "show mod"

Thanks

[m.alshaweesh@extensya.com]

Ext-Amm-Core#show mod
Chassis Type : WS-C4507R+E

Power consumed by backplane : 40 Watts

Mod Ports Card Type Model Serial No.
---+-----+--------------------------------------+------------------+-----------
1 48 10/100/1000BaseT EEE (RJ45) WS-X4748-RJ45-E CAT2127L0YF
2 48 10/100/1000BaseT EEE (RJ45) WS-X4748-RJ45-E CAT2127L6SY
3 4 Sup 8L-E 10GE (SFP+), 1000BaseX (SFP) WS-X45-SUP8L-E CAT2128L74N
4 4 Sup 8L-E 10GE (SFP+), 1000BaseX (SFP) WS-X45-SUP8L-E CAT2128L6XQ

M MAC addresses Hw Fw Sw Status
--+--------------------------------+---+------------+----------------+---------
1 3890.a505.e834 to 3890.a505.e863 1.1 Ok
2 500f.8030.beb0 to 500f.8030.bedf 1.1 Ok
3 70db.987c.ba80 to 70db.987c.ba83 1.0 15.1(1r)SG6 03.09.00.E Ok
4 70db.987c.ba84 to 70db.987c.ba87 1.0 15.1(1r)SG6 03.09.00.E Ok

Mod Redundancy role Operating mode Redundancy status
----+-------------------+-------------------+----------------------------------
3 Active Supervisor SSO Active
4 Standby Supervisor SSO Standby hot

[m.alshaweesh@extensya.com]

is there any configuration for STP in case of fiber connection ?? 

[chrihussey]

Don't think it is a spanning tree issue.

Did you do a no shut, and can you configured "speed 1000" on the interface?

Then post the output of "show interface" for both interfaces

[m.alshaweesh@extensya.com]

Ext-Amm-Core#sh int t3/1

TenGigabitEthernet3/1 is up, line protocol is

Ext-Amm-Core#sh int t3/1
TenGigabitEthernet3/1 is up, line protocol is up (connected)
Hardware is Ten Gigabit Ethernet Port, address is 70db.987c.ba80 (bia 70db.987c.ba80)
MTU 1500 bytes, BW 1000000 Kbit/sec, DLY 10 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 1000Mb/s, link type is auto, media type is 1000BaseSX
input flow-control is off, output flow-control is off
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)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
836 packets input, 203605 bytes, 0 no buffer
Received 833 broadcasts (833 multicasts)
0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
836 packets output, 203605 bytes, 0 underruns
0 output errors, 0 collisions, 8 interface resets
0 unknown protocol drops
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out

Ext-Amm-Core#show spanning-tree vlan 205

VLAN0205
Spanning tree enabled protocol rstp
Root ID Priority 32973
Address 5897.1e07.2680
Cost 19
Port 10 (GigabitEthernet1/10)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec

Bridge ID Priority 32973 (priority 32768 sys-id-ext 205)
Address 70db.987c.ba80
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 sec

Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/10 Root FWD 19 128.10 P2p
Gi1/35 Desg FWD 4 128.35 P2p
Te3/1 Back BLK 4 128.257 P2p

[m.alshaweesh@extensya.com]

the image for edge switch ad the show command is for core switch

[chrihussey]

So it looks as if there is a loop in your network and the t3/1 is a backup port. See the link below:

https://www.cisco.com/c/en/us/support/docs/lan-switching/spanning-tree-protocol/24062-146.html

You need to take a closer look at VLAN 205 and find the other path back to the root.

Hope this makes sense and helps

[m.alshaweesh@extensya.com]

there is no loop put because fiber has two path one for TX and the other one for RX this is the cause of blocking  this port 

[chrihussey]

That should not be the case. Recommend going to the edge switch and do the same "sh spanning-tree vlan 205" and see what the root port is on that switch.

[m.alshaweesh@extensya.com]

edge switch is not live for now and just have one fiber cable on int g1/0/49 (trunk)

[chrihussey]

Please post the config of the edge switch and the output of "sh cdp nei"

Thanks