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loop detect message in nexus

suthomas1
Level 6
Level 6

‎10-27-2013 07:15 AM - edited ‎03-07-2019 04:15 PM

Hi,

One of our networks currently has a nexus 5548 acting as core. There are 2248/2232 connected to this as fex members.

There is also another nexus 5K connected as edge switch to this core.

We'r getting following messages on the core switch,

CORE_SW %$ VDC-1 %$ %FWM-2-STM_LOOP_DETECT: Loops detected in the network for mac dc5a.4d1e.5b0d

among ports Eth1/2 and Eth1/4 vlan 41 - Disabling dynamic learn  notifications for 180 seconds 

CORE_SW %$ VDC-1 %$ %FWM-2-STM_LEARNING_RE_ENABLE: Re enabling dynamic  learning on all interfaces

Appreciate help on this errors.

Thanks in advance.

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0 Helpful
4 Replies 4

Reza Sharifi
Hall of Fame
Hall of Fame

‎10-27-2013 08:03 AM

Hi,

Is the edge 5500 connected to the core 5500 via 2 links (e1/2 and e1/4 vlan 41)?

Is spanning tree configured on the switches?

Can you post relavent configs from both 5ks?

HTH

suthomas1
Level 6
Level 6
In response to Reza Sharifi

‎10-27-2013 09:46 AM

Thanks Reza for the reply.

The edge 5500 is connected to Nexus Core 5500  via port-channel.

We haven't configured any spanning tree commands specifically on the switches, hence i believe it should just be the default ones.

I do not hold access to these as of now. If you can let me know what outputs you need & what to check with commands, i'll request it from our subsidary owning the network.

Appreciate your kind assistance.

0 Helpful

Reza Sharifi
Hall of Fame
Hall of Fame
In response to suthomas1

‎10-27-2013 02:01 PM

Hi
Can you post
Sh spann vla 41
Sh run spanning
Sh po summ
Are both physical ports are up and up as part of the po?
What interfaces are in the po?

HTH

Sent from Cisco Technical Support iPad App

suthomas1
Level 6
Level 6
In response to Reza Sharifi

‎10-29-2013 01:48 AM

Hi,

edge-5500 is connected to Core-5500 via e1/25 & e1/26 using Po50

interface Ethernet1/25

  switchport mode trunk

  channel-group 50 mode active

interface Ethernet1/26

  switchport mode trunk

  channel-group 50 mode active

interface port-channel50

  description Etherchannel to edge-5500

  switchport mode trunk

CORE_SW_1# sh spanning-tree vla 41

VLAN0041

  Spanning tree enabled protocol rstp

  Root ID    Priority    32778

             Address     002a.6a34.8401

             Cost        3

             Port        133 (Ethernet1/5)

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

  Bridge ID  Priority    32829  (priority 32768 sys-id-ext 61)

             Address     002a.6a39.8b41

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

Interface        Role Sts Cost      Prio.Nbr Type

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

Po50             Desg FWD 1         128.4145 P2p

Eth1/2           Desg FWD 2         128.130  P2p

Eth1/5           Root FWD 2         128.133  P2p

Eth1/6           Altn BLK 2         128.134  P2p

Eth1/10          Desg FWD 2         128.138  P2p

Eth101/1/1       Desg FWD 4         128.1153 Edge P2p

Eth101/1/2       Desg FWD 4         128.1154 Edge P2p

Eth101/1/8       Desg FWD 19        128.1160 Edge P2p

Eth101/1/9       Desg FWD 4         128.1161 Edge P2p

Eth101/1/10      Desg FWD 4         128.1162 Edge P2p

Eth101/1/11      Desg FWD 19        128.1163 Edge P2p

Eth101/1/13      Desg FWD 4         128.1165 Edge P2p

Eth101/1/14      Desg FWD 4         128.1166 Edge P2p

Eth101/1/16      Desg FWD 4         128.1168 Edge P2p

Output of sh run spanni:

interface Ethernet1/1

  spanning-tree port type edge

interface Ethernet1/5

  spanning-tree port type edge

interface Ethernet1/6

  spanning-tree port type edge

interface Ethernet1/7

  spanning-tree port type edge

interface Ethernet1/8

  spanning-tree port type edge

interface Ethernet1/9

  spanning-tree port type edge

interface Ethernet1/13

  spanning-tree port type edge

interface Ethernet1/14

  spanning-tree port type edge

interface Ethernet1/15

  spanning-tree port type edge

interface Ethernet1/16

  spanning-tree port type edge

interface Ethernet1/19

  spanning-tree port type edge

interface Ethernet1/20

  spanning-tree port type edge

interface Ethernet1/21

  spanning-tree port type edge

interface Ethernet1/22

  spanning-tree port type edge

interface Ethernet101/1/1

  spanning-tree port type edge

interface Ethernet101/1/2

  spanning-tree port type edge

interface Ethernet101/1/3

  spanning-tree port type edge

interface Ethernet101/1/4

  spanning-tree port type edge

interface Ethernet101/1/5

  spanning-tree port type edge

interface Ethernet101/1/6

  spanning-tree port type edge

interface Ethernet101/1/7

  spanning-tree port type edge

interface Ethernet101/1/8

  spanning-tree port type edge

interface Ethernet101/1/9

  spanning-tree port type edge

interface Ethernet101/1/10

  spanning-tree port type edge

interface Ethernet101/1/11

  spanning-tree port type edge

interface Ethernet101/1/12

  spanning-tree port type edge

interface Ethernet101/1/13

  spanning-tree port type edge

interface Ethernet101/1/14

  spanning-tree port type edge

interface Ethernet101/1/15

  spanning-tree port type edge

interface Ethernet101/1/16

  spanning-tree port type edge

interface Ethernet101/1/17

  spanning-tree port type edge

interface Ethernet101/1/18

  spanning-tree port type edge

interface Ethernet101/1/19

  spanning-tree port type edge

interface Ethernet101/1/20

  spanning-tree port type edge

interface Ethernet101/1/21

  spanning-tree port type edge

interface Ethernet101/1/22

  spanning-tree port type edge

interface Ethernet101/1/23

  spanning-tree port type edge

interface Ethernet101/1/24

  spanning-tree port type edge

interface Ethernet101/1/25

  spanning-tree port type edge

interface Ethernet101/1/26

  spanning-tree port type edge

interface Ethernet101/1/27

  spanning-tree port type edge

interface Ethernet101/1/28

  spanning-tree port type edge

interface Ethernet101/1/29

  spanning-tree port type edge

interface Ethernet101/1/30

  spanning-tree port type edge

interface Ethernet101/1/31

  spanning-tree port type edge

interface Ethernet101/1/32

  spanning-tree port type edge

interface Ethernet101/1/33

  spanning-tree port type edge

interface Ethernet101/1/34

  spanning-tree port type edge

interface Ethernet101/1/35

  spanning-tree port type edge

interface Ethernet101/1/36

  spanning-tree port type edge

interface Ethernet101/1/37

  spanning-tree port type edge

interface Ethernet101/1/38

  spanning-tree port type edge

interface Ethernet101/1/39

  spanning-tree port type edge

interface Ethernet101/1/40

  spanning-tree port type edge

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

CORE_SW_1#sh port-channel summary

Flags:  D - Down        P - Up in port-channel (members)

        I - Individual  H - Hot-standby (LACP only)

        s - Suspended   r - Module-removed

        S - Switched    R - Routed

        U - Up (port-channel)

        M - Not in use. Min-links not met

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

Group Port-       Type     Protocol  Member Ports

      Channel

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

40    Po40(RU)    Eth      NONE      Eth1/17(P)   Eth1/18(P)  

50    Po50(SU)    Eth      LACP      Eth1/25(P)   Eth1/26(P)  

101   Po101(SU)   Eth      NONE      Eth1/27(P)   Eth1/28(P)  

102   Po102(SU)   Eth      NONE      Eth1/29(P)   Eth1/30(P)  

103   Po103(SU)   Eth      NONE      Eth1/31(P)   Eth1/32(P)  

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

CORE_SW_2# sh spanning-tree vla 41

VLAN0041

  Spanning tree enabled protocol rstp

  Root ID    Priority    32778

             Address     002a.6a34.8401

             Cost        4

             Port        4145 (port-channel50)

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

  Bridge ID  Priority    32829  (priority 32768 sys-id-ext 61)

             Address     002a.6a34.8401

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

Interface        Role Sts Cost      Prio.Nbr Type

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

Po50             Root FWD 1         128.4145 P2p

Please help with suggestions. Thanks.

0 Helpful
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