CISCO SG500 VLAN issue

[fiza]

In our Primary School the network is connected via Cisco SG500 switches. These have been in before we started looking after the school and have always worked just fine.

Since September we are finding that ports are randomly losing their VLAN identities. A port is set to Untagged on VLAN 3 but either within a few minutes or hours it will lose VLAN 3 and Drop to 1U, 2T or just 1U. It just doesnt make sense. We have always done the settings via the GUI and always save the running config to startup. We will get reports that APs are not working or that phones have lost connection and it is always down to the VLAN dropping off.

 

Is it better to do changes via CLI rather than the GUI. Could it be an issue with the GUI?

 

Or is it time to replace these SG500 switches?

[RedwayNetworks_Michael]

Hi Fiza,

 

I just ran this past one of our engineers for you, please see below

 

I'd be interested to know if the switches have been running for a while without any changes being made and you have only noticed this behaviour, or whether you've been making changes for a while and this behaviour has just started? If it is the former, then a firmware upgrade (assuming you aren't already running the latest version) may help. If changes have been made consistently without issue and the behaviour has just started, then that sounds a little bit more like the switches are starting to go and certainly having a backup plan to replacement wouldn't be a bad idea.

 

Personally, I've not had an issue configuring the SG line through GUI or the CLI. The CLI is a different beast to regular Cisco IOS as I think it's based on code created by Linksys before they were acquired by Cisco, but either configuration method has worked in the as well as the other for me. If you want to let me know what version of firmware you have as well, we can take a quick look at the release notes and see if there are any known bugs.

 

 

In regards to support on the switches the support is announced to come to an end in 2023 so it may be a good idea to plan to replace them.

[fiza]

Hi Michael - Thanks for the response. It is the former, the switches have been running for a while without any changes being made and we have only just noticed this behaviour. We will look at the firmware upgrades as I am sure they will not be upto date.

[RedwayNetworks_Michael]

Hi Fiza,

 

No problem at all, happy to help. Please do let us know how you get on, also if you want to us to put a plan together for you to replace let me know.

[fiza]

Hi Michael - I have sent you a PM.

[hellgate24]

Used to get this on the SG350 switches. It was down to auto smartport kicking in and changing the port config to what the switch thought it needed to be. Turned this off on a port by port basis through the CLI and my issues went away.

[fiza]

Used to get this on the SG350 switches. It was down to auto smartport kicking in and changing the port config to what the switch thought it needed to be. Turned this off on a port by port basis through the CLI and my issues went away.

 

Hi just tried that through the GUI as I have no idea about the commands I would need to use with the CLI but made no difference.

[RobD]

I really wouldnt be suprised if its smartport. Its a nightmare, here's how I normally disable it:

 

https://www.cisco.com/c/en/us/support/docs/smb/switches/cisco-350-series-managed-switches/smb5842-configure-auto-smartport-properties-switch-through-cli.html

[fiza]

@hellgate24 @RobD

 

Thanks both. I disabled smartport but initially it made no difference, I then administratively switched the affected ports off and on again which then did the trick. Has been stable now for a few days and devices are connecting.