06-22-2007 03:13 AM - edited 03-05-2019 04:54 PM
Hi,
Is there any way to keep a vlan interface up without having any active physical ports in the vlan?
Thanks,
J
06-22-2007 03:43 AM
Hi,
Try disabling the autostate feature you can accomplish this by using "autostate disable" (its a hidden command), the autostate feature is enabled by default, but i guess that on IOS based switches, this feature cannot be disabled.
HTH,
Mohammed Mahmoud.
06-22-2007 03:55 AM
Hi Mohammed,
Thanks for your response - I'm pretty sure that's what I need to do, but I can't find the correct command to use. Do you know what it would be on a c3750 please?
Thank you,
J
06-22-2007 04:00 AM
Forgot to say it's wersion 12.2(25)
06-22-2007 04:01 AM
Hi,
Unfortuantely, i've confirmed that it can't be disabled on IOS based switches, only on CatOS switches using the "autostate disable" hidden command.
HTH,
Mohammed Mahmoud.
06-22-2007 08:07 AM
Hi,
If you only have a single switch then it is not possible, or at least i don't know.
But If you have 2 switches linked via Trunk then your VLAN will be up regardless of any port assignment. If you have a Router on the Stick setup then change the switchport which connects to that router to be a trunk. and configure Eth port on the router with sub-interfaces. This should help.
Hope this helps !!
Shaheen
06-22-2007 08:52 AM
Thanks for your reply - there is actually l3 routing between switches so no trunking. I want this vlan to reside purely on one sight (where only the one switch is).
06-23-2007 12:28 AM
Hi,
The answer would be that you need at least one port in the VLAN in the connected state or there should be a trunk in the connected state, IMHO unfortunately no way around.
HTH,
Mohammed Mahmoud.
06-23-2007 01:31 AM
In my opinion, an interface Vlan remains up as long as you do not shut it down.
Do you mean that it goes sometimes down without any reason ?
You can also use routed interface, that would avoid you to set a port in that Vlan.
06-25-2007 04:51 AM
Hi Guillaume,
If the SVI interface is created but the VLAN is not configured on the switch the SVI interface will be down/down, if the VLAN is created on the switch but no port assigned to this VLAN is UP/UP (or an UP/UP trunk) the SVI stays up/down.
HTH,
Mohammed Mahmoud.
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