I had a HP switch and a Meraki switch crash a enterprise network cause the HP native vlan 1 didn't work with Meraki (Cisco). I was able to fix the issue by switching both to admin vlan 100, but the voip phones dropped on HP. Voip phones only working on vlan 1. I the only way I can get it to work is with Meraki with untagged vlan and HP set to vlan 1, super weird, but then I read up on some super old Cisco manual about native vs default and untagged. It said that Cisco with 3rd party switches treats them as untagged instead of vlan native, which makes sense cause the voip phones dropped. Thnen I tried HP vlan 1 native (default for HP) and on Cisco Meraki to admin vlan 1 and changed native vlan 1 to 100. super weird stuff but that worked. but for years still not sure how or who /where/why Cisco has a native vs default vs administrative vs untagged and how it plays with 3rd party switches....
the company originally had set it up as a flat network. aka everything vlan 1 or default untagged and no trunking any where, but there's now public facing connections and I'm like "we need to seperate the network". so the vlan creation began
I couldn't just put the voip phones on vlan 1 cause the workstations are plugged into the voip phones and the phones to the HP switch meaning the workstations would connect with vlan 1 and they need vlan 10 for the windows server active directory.