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Implications of creating a new VLAN?

xxcaligulaxx
Level 1
Level 1

Is it recommended to create a new VLAN within a switched environment, involving numerous switches with redundant links, during the normal working day. When the new VLAN is created am I correct in thinking that the trunk links will go through the listening, learning , forwarding/blocking etc. During this time data will not be passed through the trunks and therfore conenctivity between the switches will be impacted for up to 45 seconds?

Would good practise be to cover this with a CM and carry out the change outwith normal working hours.

Or am I worrying about nothing and it is perfectly acceptable to create vlans anytime?

4 Replies 4

Kevin Dorrell
Level 10
Level 10

Normally if your VTP domain is working correctly, you can add a VLAN without any impact. You should add the VLAN at a VTP server switch. The switches maintain a separate Spanning Tree for each VLAN, so the only VLAN that will go through the convergence process will be the new one.

I say "normally" just as a disclaimer, in case your architecture is unusual in any way. On my network, I can add and delete VLANs with impunity.

Kevin Dorrell

Luxembourg