Port GigabitEthernet2 moving from Disabled to Blocking

[Rajstopy]

Dear all,

I already posted about the same issue some time ago, but still present in my logs as you can show. I notice a bunch of such messages always on the same port.

Can someone give me a clue, about what bould be the reason?

<182>1 2021-12-21T14:55:36.654Z 192.168.10.28-1 LLDP-6-NEIGHBOR_DISCOVER proto_lldp.c(5184) %% New neighbor on port GigabitEthernet1: Chassis ID F0:2F:74:1F:45:B3, Port ID F0:2F:74:1F:45:B3
<182>1 2021-12-21T14:27:00.924Z 192.168.10.28-1 STP-6-PORT_STATE proto_stp.c(820) %% Port GigabitEthernet2 moving from Blocking to Forwarding
<182>1 2021-12-21T14:26:58.924Z 192.168.10.28-1 STP-6-PORT_STATE proto_stp.c(820) %% Port GigabitEthernet2 moving from Disabled to Blocking
<181>1 2021-12-21T14:26:58.724Z 192.168.10.28-1 TRAPMGR-5-PORT_LINK_UP ksi_snmp.c(232) %% Interface GigabitEthernet2 link up
<182>1 2021-12-21T14:26:55.924Z 192.168.10.28-1 STP-6-PORT_STATE proto_stp.c(820) %% Port GigabitEthernet2 moving from Blocking to Disabled
<181>1 2021-12-21T14:26:55.824Z 192.168.10.28-1 TRAPMGR-5-PORT_LINK_DOWN ksi_snmp.c(230) %% Interface GigabitEthernet2 link down
<182>1 2021-12-21T14:26:54.924Z 192.168.10.28-1 STP-6-PORT_STATE proto_stp.c(820) %% Port GigabitEthernet2 moving from Disabled to Blocking
<181>1 2021-12-21T14:26:54.744Z 192.168.10.28-1 TRAPMGR-5-PORT_LINK_UP ksi_snmp.c(232) %% Interface GigabitEthernet2 link up
<182>1 2021-12-21T14:26:51.924Z 192.168.10.28-1 STP-6-PORT_STATE proto_stp.c(820) %% Port GigabitEthernet2 moving from Forwarding to Disabled
<181>1 2021-12-21T14:26:51.834Z 192.168.10.28-1 TRAPMGR-5-PORT_LINK_DOWN ksi_snmp.c(230) %% Interface GigabitEthernet2 link down
<182>1 2021-12-21T14:26:32.924Z 192.168.10.28-1 STP-6-PORT_STATE proto_stp.c(820) %% Port GigabitEthernet2 moving from Blocking to Forwarding
<182>1 2021-12-21T14:26:29.924Z 192.168.10.28-1 STP-6-PORT_STATE proto_stp.c(820) %% Port GigabitEthernet2 moving from Disabled to Blocking
<181>1 2021-12-21T14:26:29.894Z 192.168.10.28-1 TRAPMGR-5-PORT_LINK_UP ksi_snmp.c(232) %% Interface GigabitEthernet2 link up
<182>1 2021-12-21T14:26:26.924Z 192.168.10.28-1 STP-6-PORT_STATE proto_stp.c(820) %% Port GigabitEthernet2 moving from Blocking to Disabled
<181>1 2021-12-21T14:26:26.794Z 192.168.10.28-1 TRAPMGR-5-PORT_LINK_DOWN ksi_snmp.c(230) %% Interface GigabitEthernet2 link down
<182>1 2021-12-21T14:26:25.924Z 192.168.10.28-1 STP-6-PORT_STATE proto_stp.c(820) %% Port GigabitEthernet2 moving from Disabled to Blocking
<181>1 2021-12-21T14:26:25.844Z 192.168.10.28-1 TRAPMGR-5-PORT_LINK_UP ksi_snmp.c(232) %% Interface GigabitEthernet2 link up
<182>1 2021-12-21T14:26:23.174Z 192.168.10.28-1 STP-6-PORT_STATE proto_stp.c(820) %% Port GigabitEthernet2 moving from Forwarding to Disabled

[schumaku]

Wonky link, wonky cable, wonky peer adapter/system - link going down and up. Link seems to be bouncing under some unknown conditions.

No STP variant does ever take the physical Ethernet link down.

Also strange, the last LLDP new neighbor almost 30 minutes after the link came up. Here I could admit that this might be from a VM or the link bridged to that other adapter on the far end.

Same issue on all ports, or just the #2?

PS. Requesting a moderator to move this thread to the appropiate "Smart Plus And Smart Pro Managed Switches Forum" community section.

[Rajstopy]

Thank you very much for your answer, very appreciated.

Actually I experience this behavior only on one port. This port is linked to my ESXi management NIC so I don't understand why a VM could be involved.

I must admit I'm a little bit lost.

Cheers,

[schumaku]

Already moved the ESXi link to a different port on the switch?

The bouncing link should be visible on the ESXi host, too.

[schumaku]

Ignore my comment ref. the LLDP discovery.

<182>1 2021-12-21T14:55:36.654Z 192.168.10.28-1 LLDP-6-NEIGHBOR_DISCOVER proto_lldp.c(5184) %% New neighbor on port GigabitEthernet1: Chassis ID F0:2F:74:1F:45:B3, Port ID F0:2F:74:1F:45:B3

This is a different port (GigabitEthernet1).

[Rajstopy]

Many thanks again for trying to help me on that issue!

So far, since I changed the network cable, I didn't observe those errors anymore. I need to keep it under observation for some days, anyway.

However I'm not quiet at all because I suspect another underlaying problem. I've 2 ports that are bliking steadily. Obviously I've some constant traffic because of IP cameras connected to my LAN, but the blinking frequency looks weird to me. I did supect a network loop but I really don't know where it could be located... I don't know which kind of network trafic may lead to a such high frequency and permanent blinking.

On port is connected to my ESXi, the other is an uplink to another unmanaged Netgear swtich.

I could maybe try a pcap capture on the ESXi related port... Or any other suggestion for investigation?

[schumaku]

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@Rajstopy wrote:

However I'm not quiet at all because I suspect another underlaying problem. I've 2 ports that are bliking steadily. Obviously I've some constant traffic because of IP cameras connected to my LAN, but the blinking frequency looks weird to me. I did supect a network loop but I really don't know where it could be located... I don't know which kind of network trafic may lead to a such high frequency and permanent blinking.

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Activity LED behaviour can be different depending on the switch model. Small packets on a high rate might look funny sometimes, indeed. Network cameras show this typically. Another example is the Flight Simulator when enabled to "broadcast" ADS-B-like and more to the LAN (yeah, really broadcast).  

With STP active (and enabled on the ports), and then once more also with the L2 Loop prevention enabled, its very unlikely an undetected loop. These switches (like all Smart Managed and higher) would shutdown a port, and not use the "both LED" flashing you might know from some unmanaged or Plus switches.