Looking to get vlans to auto Up on cisco L3 Switch

By coolbiker ·
I have currently 2 vlans set to be trunked with dot1q. The router is running rip version 2 and all vlans have ip's and used vlans are on a subinterface on the router.

The problem here is that when I plug in on the switch , the vlans do not come up on thier own. I can use the "no shutdown" command for each vlan but that is not a viable option to me.

This switch is a layer 3 cisco switch (3550?)
Any Help would be great.

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well I've heard some good ones on here but this certainly tops it

by Screen Gems In reply to Looking to get vlans to a ...

Dude, you do know that Vlans are logical groupings of switchports for a subnet and that there is no "turn on" or "turn off" for vlans on a switch?

Well, if you did, have a laugh, if you didn't well reading is enlightenment...

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There is a "no shutdown" comand for vlan

by coolbiker In reply to well I've heard some good ...

On cisco there is a " no shutdown" command where I can Manually bring it up meaning Ive turn on in my words. Without them up you can't ping to that level.

I just can't get the setting to work for my switch to have these vlans go up state without that manual "no shutdown"

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No Shutdown

by Donmecca In reply to There is a "no shutdown" ...

I understand what you by turning on the vlan. However, I would need more information on your network so I would provide an example of what you are trying to achieve. How many vlans do you have, subnets, and etc?

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3 vlans 3 subnets 1 trunk to route

by coolbiker In reply to No Shutdown

Each vlan had ts own subnet 0.1,2.1,3.1...
They were trunked to on router running rip v2

It sounded like with 12.1 or greater of cisco ios this should have been no mess with configs to get to work, since an "autoset" feature sounds like it should be on by default and the devices I had worked with were default settings( this was a school test environment so the hardware was attempted to stay clean configurations)

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Dude, your subinterfaces on the 3550 are like router interfaces

by CG IT In reply to 3 vlans 3 subnets 1 trunk ...

you use the no shut command to bring up the interface,

but Vlans do not have a no shut command. Vlans are simply a logical grouping of switchports in a subnet. Switchports are not shutdown by default.

vlans only allow traffic for its vlan. for intervlan traffic, you have to use a router to route traffice between them.

Trunking provides the path to different vlans for the router.

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Automatically Shut and No shut Sub interfaces in a cisco 1841

by shiruz In reply to Looking to get vlans to a ...

I have a p2p link that requires a shut/noshut every 5 minutes. My ISP has looked into it and confirmed that all is well however am unable to reach the branch after 5 minutes unless I manually shut/no shut the sub interface on my router. I have tried to reconfigure that sub interface, given it different IPs but no success. on sh int fa 0/1.x the sub interface appears to be up. I have tried using event management which has not worked so far.

Question 1: What would cause a sub interface to behave this way and what are the remedies?
Question 2: Apart from event management, what other way is available for automatically refreshing this sub interface?

Kindly assist.


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