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Total Mental block for VLANs

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stephen.stack
Level 4
Level 4

‎08-28-2008 07:44 AM - edited ‎03-06-2019 01:03 AM

Do i need a vlan configured on a switch in ordre for traffic on that vlan to traverse the switch on a trunk.

So, i have trunks between switch 1 and 2. and i have a trunk between switch 1 and 3. I have access ports in vlan 100 on both siwtch 2 and 3. Does switch 1 need to have vlan 100 enabled to allow traffic between switch 2 and 3.

Where is my mind gone???

Stephen

========================== http://www.rconfig.com A free, open source network device configuration management tool, customizable to your needs! - Always vote on an answer if you found it helpful
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Mark Yeates
Level 7
Level 7
In response to stephen.stack

‎08-28-2008 08:13 AM

VLANs are created on Layer 2 switches to control broadcasts and enforce the use of a Layer 3 device for communications. Each VLAN is created in the local switch's database for use. If a VLAN is not known to a switch, that switch cannot transfer traffic across any of its ports for that VLAN. So in order for VLAN 100 to be trunked across switch 1 it needs to be aware of VLAN 100.

HTH,

Mark

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Mark Yeates
Level 7
Level 7

‎08-28-2008 07:49 AM

Stephen,

Yes, you will want to create a layer 2 VLAN for VLAN 100 for switches 2 and 3 VIA switch 1.

HTH,

Mark

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stephen.stack
Level 4
Level 4
In response to Mark Yeates

‎08-28-2008 07:57 AM

Ok, this is good. I'm not going mad then. Why????

========================== http://www.rconfig.com A free, open source network device configuration management tool, customizable to your needs! - Always vote on an answer if you found it helpful
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Mark Yeates
Level 7
Level 7
In response to stephen.stack

‎08-28-2008 08:13 AM

VLANs are created on Layer 2 switches to control broadcasts and enforce the use of a Layer 3 device for communications. Each VLAN is created in the local switch's database for use. If a VLAN is not known to a switch, that switch cannot transfer traffic across any of its ports for that VLAN. So in order for VLAN 100 to be trunked across switch 1 it needs to be aware of VLAN 100.

HTH,

Mark

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stephen.stack
Level 4
Level 4
In response to Mark Yeates

‎08-28-2008 08:21 AM

Thanks for reply, it is clear now.

========================== http://www.rconfig.com A free, open source network device configuration management tool, customizable to your needs! - Always vote on an answer if you found it helpful
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Mark Yeates
Level 7
Level 7
In response to stephen.stack

‎08-28-2008 08:55 AM

No problem. Glad I was able to clear things up for you.

Mark

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