XGS1930 LLDP & CPU High

SmileitsMe

hello, we have some XGS 1930 and HP 2530 Switches running with Voice Lan via LLDP_MED, and some other V-Lans.

Customer complains about breaking connections (VM)

Sometimes Switch shows hight CPU

946 2024-04-17T15:45:49+02:00 IN system: CPU utilization is over 100 and keep 5 seconds, driver count = 64

and many lldp entries where we are not able to identify where they come from

10000+ entries/Day

example

9982 2024-04-17T08:29:09+02:00 IN interface: LLDP Remote topologyChange
9983 2024-04-17T08:29:09+02:00 IN interface: LLDP Remote topologyChange
9984 2024-04-17T08:29:09+02:00 IN interface: LLDP Remote topologyChange
9985 2024-04-17T08:29:09+02:00 IN interface: LLDP Remote topologyChange
9986 2024-04-17T08:29:09+02:00 IN interface: LLDP Remote topologyChange
9987 2024-04-17T08:29:09+02:00 IN interface: LLDP Remote topologyChange
9988 2024-04-17T08:29:09+02:00 IN interface: LLDP Remote topologyChange
9989 2024-04-17T08:28:53+02:00 IN interface: LLDP Remote topologyChange
9990 2024-04-17T08:28:42+02:00 IN interface: LLDP Remote topologyChange
9991 2024-04-17T08:28:39+02:00 IN interface: LLDP Remote topologyChange
9992 2024-04-17T08:28:39+02:00 IN interface: LLDP Remote topologyChange
9993 2024-04-17T08:28:39+02:00 IN interface: LLDP Remote topologyChange
9994 2024-04-17T08:28:39+02:00 IN interface: LLDP Remote topologyChange

so what can cause this? Thanks

Zyxel_Melen

Hi @SmileitsMe,

Could you help to collect the tech support after the issue happens for me to check?

Please reference this FAQ to collect the tech support:

https://community.zyxel.com/en/discussion/3245/how-to-collect-the-diagnostic-info

And what is the topology of this case?

SmileitsMe

Wrote you PN with Files

Zyxel_Melen

Hi @SmileitsMe,

Thanks for the tech support file. The reason for printing the log "interface: LLDP Remote topologyChange" is that you have enabled "lldp med topology-change-notification" on all of the ports. May I know if you need this feature enabled in this network? Could you disable it temporarily? Since the log "interface: LLDP Remote topologyChange" is printing so quickly, sometimes seven-time changes in one second, I assume this might cause the switch to be busy.

SmileitsMe

ok.. we will test this.

SmileitsMe

have disabled this at 201.. but also LLDP will be written.. has the switch to be restarted to disable this?

1 2024-04-19T11:53:43+02:00 IN interface: LLDP Remote topologyChange
2 2024-04-19T11:53:43+02:00 IN interface: LLDP Remote topologyChange
3 2024-04-19T11:53:43+02:00 IN interface: LLDP Remote topologyChange
4 2024-04-19T11:53:43+02:00 IN interface: LLDP Remote topologyChange
5 2024-04-19T11:53:43+02:00 IN interface: LLDP Remote topologyChange
6 2024-04-19T11:53:43+02:00 IN interface: LLDP Remote topologyChange
7 2024-04-19T11:53:43+02:00 IN interface: LLDP Remote topologyChange
8 2024-04-19T11:53:42+02:00 IN interface: LLDP Remote topologyChange
9 2024-04-19T11:53:22+02:00 IN interface: LLDP Remote topologyChange
10 2024-04-19T11:53:13+02:00 IN interface: LLDP Remote topologyChange
11 2024-04-19T11:53:13+02:00 IN interface: LLDP Remote topologyChange
12 2024-04-19T11:53:13+02:00 IN interface: LLDP Remote topologyChange
13 2024-04-19T11:53:13+02:00 IN interface: LLDP Remote topologyChange
14 2024-04-19T11:53:13+02:00 IN interface: LLDP Remote topologyChange
15 2024-04-19T11:53:12+02:00 IN interface: LLDP Remote topologyChange
16 2024-04-19T11:53:12+02:00 IN interface: LLDP Remote topologyChange
17 2024-04-19T11:53:12+02:00 IN interface: LLDP Remote topologyChange
18 2024-04-19T11:53:08+02:00 IN system: Save system configuration 1 successfully

SmileitsMe

CPU Utilization
Current (%) 37.76 is this normal ?

Zyxel_Melen

https://community.zyxel.com/en/discussion/comment/64679#Comment_64679

Hi @SmileitsMe,

My mistake. "lldp med topology-change-notification" is to send notification if local has topology change. Please disable "lldp notification" then the syslog will not print "LLDP Remote topologyChange" when receive topology-change-notification LLDP from other devices.

CPU Utilization
Current (%) 37.76

About CPU utilization you posted, it is normal. The CPU utilization depends on current tasks the switch handling. The more tasks, the higher CPU utilization it will be.

SmileitsMe

Hi Melen!

Ok… had disabled med notification.. did not help.. switch crashed again when trying to get tech logs.. but the other switches are ok?

So config was given to a new hardware.. same issue.

may this is really a firmware problem?

ok read your notice.. will disable lldp notification.. but will this not disable the ability for the Devices using lldp?

cause we have programmed the switch to sent voip devices via lldp med to right vlan.

Zyxel_Melen

Hi @SmileitsMe,

Ok… had disabled med notification.. did not help.. switch crashed again when trying to get tech logs.. but the other switches are ok?

According to the tech supports you provided from switches 201 & 206, I didn't find any crash logs. You mentioned "switch crashed again when trying to get tech logs", may I know if the switch rebooted or was just inaccessible? If the switch didn't reboot, that might be another issue.

By the way, you have mentioned in the private message "the 200 and 201 are connected via 10G (usually Port 50 to Port50). When the 200 rebootet the uplink to 201 was offline. "

May I know if you mean you cannot connect to switch 200?

Also, I noticed that port 50 of switch 201 was errdisable by loopguard.

In addition, switch 206 also occurred errdisable by loopguard on port 12.

Please check if this site has any connections that will cause a loop.

ok read your notice.. will disable lldp notification.. but will this not disable the ability for the Devices using lldp?

"lldp notification" will not disable the Voice VLAN since the Voice VLAN uses "lldp med network-policy" to assign the VLAN tag. Please disable "lldp notification" and monitor if the CPU utilization is over 100 and keep 5 seconds again.

If the above actions are done, but the VM connections still have problems, please share the detailed topology with me. So, I can better investigate what could cause the disconnected issue.