N3K link flapping log

[wenfengji]

Problem description：The link between N3K and C6800,C6800'port have been shutdown,but n3k still coming up some link flapping log.The logs are as follows:

Topology：

N3K ETH1/24(no shutdown) --- Ten 5/1(shutdown) 6800-2

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2022 Jun 23 21:11:08.367 N3K %ETHPORT-5-SPEED: Interface Ethernet1/24, operational speed changed to 10 Gbps
2022 Jun 23 21:11:08.367 N3K %ETHPORT-5-IF_DUPLEX: Interface Ethernet1/24, operational duplex mode changed to Full
2022 Jun 23 21:11:08.367 N3K %ETHPORT-5-IF_RX_FLOW_CONTROL: Interface Ethernet1/24, operational Receive Flow Control state changed to off
2022 Jun 23 21:11:08.367 N3K %ETHPORT-5-IF_TX_FLOW_CONTROL: Interface Ethernet1/24, operational Transmit Flow Control state changed to off
2022 Jun 23 21:11:08.409 N3K %ETHPORT-5-IF_UP: Interface Ethernet1/24 is up in mode trunk
2022 Jun 23 21:11:08.467 N3K %ETHPORT-5-IF_DOWN_LINK_FAILURE: Interface Ethernet1/24 is down (Link failure)
2022 Jun 23 21:16:18.333 N3K %ETHPORT-5-SPEED: Interface Ethernet1/24, operational speed changed to 10 Gbps
2022 Jun 23 21:16:18.333 N3K %ETHPORT-5-IF_DUPLEX: Interface Ethernet1/24, operational duplex mode changed to Full
2022 Jun 23 21:16:18.333 N3K %ETHPORT-5-IF_RX_FLOW_CONTROL: Interface Ethernet1/24, operational Receive Flow Control state changed to off
2022 Jun 23 21:16:18.333 N3K %ETHPORT-5-IF_TX_FLOW_CONTROL: Interface Ethernet1/24, operational Transmit Flow Control state changed to off
2022 Jun 23 21:16:18.373 N3K %ETHPORT-5-IF_UP: Interface Ethernet1/24 is up in mode trunk
2022 Jun 23 21:16:18.436 N3K %ETHPORT-5-IF_DOWN_LINK_FAILURE: Interface Ethernet1/24 is down (Link failure)

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Additional tests:

1.Replacement of the N3K ETH1/24 module,the log still coming up

2.Replacement of the Fiber,the log still coming up

3.Replacement of the 6800 Ten 5/1 module,the log still coming up

4.Changing the interface from 6800 Ten5/1to Ten 5/10,logs will not appear

5.Replacement of N3K with 9200 that connect to 6800 Ten5/1,logs will not appear

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Any help or ideas would be greatly appreciated.

[balaji.bandi]

if the nexus in vPC ?  or is this part of port channel?

can you post the below information?

show run interface Ethernet1/24  

show interface Ethernet1/24  

[wenfengji]

Hi balaji.bandi

the information as below:

---------------------------------(show run interface Ethernet1/24)

interface Ethernet1/24
switchport mode trunk
switchport trunk native vlan 2

---------------------------------(show interface Ethernet1/24)

Ethernet1/24 is down (Link not connected)
admin state is up, Dedicated Interface
Hardware: 100/1000/10000 Ethernet, address: 00ea.bd60.203f (bia 00ea.bd60.203f)
Description: 
MTU 1500 bytes, BW 10000000 Kbit , DLY 10 usec
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, medium is broadcast
Port mode is trunk
auto-duplex, auto-speed, media type is 10G
Beacon is turned off
Auto-Negotiation is turned on FEC mode is Auto
Input flow-control is off, output flow-control is off
Auto-mdix is turned off
Rate mode is dedicated
Switchport monitor is off
EtherType is 0x8100
EEE (efficient-ethernet) : n/a
admin fec state is auto, oper fec state is off
Last link flapped 00:11:22
Last clearing of "show interface" counters never
482 interface resets
Load-Interval #1: 30 seconds
30 seconds input rate 0 bits/sec, 0 packets/sec
30 seconds output rate 0 bits/sec, 0 packets/sec
input rate 0 bps, 0 pps; output rate 0 bps, 0 pps
Load-Interval #2: 5 minute (300 seconds)
300 seconds input rate 0 bits/sec, 0 packets/sec
300 seconds output rate 0 bits/sec, 0 packets/sec
input rate 0 bps, 0 pps; output rate 0 bps, 0 pps
RX
550726 unicast packets 613891 multicast packets 2543689 broadcast packets
3708306 input packets 584186669 bytes
0 jumbo packets 0 storm suppression packets
0 runts 0 giants 0 CRC 0 no buffer
0 input error 0 short frame 0 overrun 0 underrun 0 ignored
0 watchdog 0 bad etype drop 0 bad proto drop 0 if down drop
0 input with dribble 0 input discard
0 Rx pause
TX
29329 unicast packets 8 multicast packets 0 broadcast packets
29337 output packets 3756437 bytes
0 jumbo packets
0 output error 0 collision 0 deferred 0 late collision
0 lost carrier 0 no carrier 0 babble 0 output discard
0 Tx pause

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

[balaji.bandi]

this is admin up, how about admin down (interface shutdown) what you see the logs (i think may be bug)

[marce1000]

         - Perform  a sanity check ,->  look at logs on the 6800 too , 

 M.

[wenfengji]

Hi marce1000

there are not any log on 6800 when link flapping log appearing in N3K.

[marce1000]

 - Could be a bug , use latest advisory release , if feasible and applicable : https://software.cisco.com/download/home/283815894/type/282088129/release/9.3(9)

 M.

[wenfengji]

Hi Marce

Is there a similar bug about this situation?