Please help clear this up, I've read too many posts that just don't get it.

If change access and distro to native vlan 5 device Mngmt vlan 100 blackhole 999

connections from core to distro should be L3, correct? What about the core switches and router do they need changing to vlan 5 also and their device Mngmt to int vlan 100? for access distro and core switches, what should be ip default-gateway?

PLease help, from reading so many posts, it seems like the answer may be just too obvious to give clear answers or noone really cares about this detail.

  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide and accept your own answer.
    – Ron Maupin
    Commented Dec 25, 2018 at 8:29

1 Answer 1


Here are two important things to remember:

  1. VLAN tagging is specific to a particular port, not the whole switch. A VLAN can be tagged on port 1, but untagged (native) on port 2.
  2. When two switches are connected with a trunk, the VLAN tagging should be the same on both trunk ports. If VLAN 100 is tagged on one side of the trunk, it should also be tagged on the other.

VLANs are layer 2 constructs, so if you have layer 3 connections, VLANs have no meaning, only IP addresses.

This question and answer might be helpful

  • But all routers and L3 switches are already set to vlan1, so I'm wondering how that native traffic passes between them if my distro and access switch are changed to native5. Commented May 10, 2018 at 15:35
  • And on the L3 router and core switch there is still the management of the device int vlan 100 in this case so you would want to communicate to those devices over your L3 connections, am I being clear enough? Commented May 10, 2018 at 15:37
  • Again, there are no VLANs on L3 ports. you may have a VLAN on your core switch, but when you connect that switch to your distro with a L3 link, all VLAN information is removed. The distro switch has no idea what VLAN you had on the core.
    – Ron Trunk
    Commented May 10, 2018 at 15:40
  • Also, you keep saying things like "my switch is set to native vlan 5." VLAN tagging is applied to switch ports, not switches in general. So your statement makes no sense.
    – Ron Trunk
    Commented May 10, 2018 at 15:47
  • In the context of moving everything from vlan 1, so there are no ports or mngmt int vlans on vlan 1, so there has to be a native. If that makes my prediciment clearer. Commented May 10, 2018 at 15:52

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