Vlan tagging issue

[thaniya]

 I am using Cisco C1000 series switch as a access switch and I have created new vlan in the core switch but it's not read by access switch. But that access switch already read other vlan but noth the newly created one? I have check trunking and all there is no configuration issue. What would be the reason for this issue

[Joseph W. Doherty]

The newly created VLAN needs to be made known to both switches.  Might be done by manual configuration on both switches or manual configuration on a VTP server switch relayed to a VTP client switch.

[marce1000]

  - If you are not using VTP then you have to create the vlan on the access switch manually,

 M.

[Jens Albrecht]

What do you mean by it's not read by access switch?

Do you use VTP to configure your Vlans? Then you need to check the VTP settings like version, domain and password.

If not, then you need to manually add the new vlan to your access switch.
A switch will simply drop frames if they have a tag for a vlan that does not exist on this switch.

So you either need to manually configure the Vlans on all your switches or use VTP to centrally manage them.

[M02@rt37]

Hello @thaniya 

What about VTP configuration on that C1000 ? Transparent or client mode ? You CORE swith is in VTP server mode ?

[MHM Cisco World]

Two reasons 

1- VTP not push vlan 

2- you use vlan number which is not accpet by c1000' 

MHM

[Joseph W. Doherty]

you use vlan number which is not accpet by c1000' 

A somewhat uncommon issue, but certainly a possible issue.  Also, I recall (?) VTP has limitations in VLAN high numbering (above 1k?).

Also, different switches often have different limits to the total number of active VLANs and STP instances they will support.

If you could further describe the VLAN environment, and what specifically you're attempting, and any error messages, we may be able to determine the specific issue, and possibility, how to mitigate it.

[Jens Albrecht]

As @Joseph W. Doherty mentioned there are certain limitations with older VTP versions.

VTP version 1 and 2 support vlan numbers up to 1001.
You can create higher vlans on the VTP server running versions 1 and 2 but they are not replicated across the VTP domain to other switches. So you do not get any error message when you e.g. create Vlan 1006 on the VTP server but it will simply not show up on any other switch in your VTP domain.

Hence you need to run VTP version 3 if you want to use vlan numbers 1006 - 4094 in your VTP domain.