Trunk and VTP question

jamesgonzo · ‎10-06-2008

Hi,

I'm just trying different ways to trunk switches.

1.) I have managed to get my L2 2950 and L3 3550 trunked and routing between vlans. I believe both switches are in vtp server mode, so what is this setup known as, I can only find vtp transparent mode and vtp server/client mode?

2.) Also what role does the Native vlan play in a trunk? I didn't use it, lots of examples use the native vlan 1.

3.) My next lab is to try vtp server/client mode, which seems pretty straight forward on paper are there any other types of trunks for the CCNA students to try?

Many thanks in advance.

Jon Marshall · ‎10-06-2008

1) It's not really "known" as anything in particular. You are just running both switches in VTP server mode. It's not transparent so VTP server/client.

2) The native vlan is the vlan on an 802.1q trunk that is not tagged with the vlan ID.

3) VTP server/client mode is not a trunk type. You have 2 trunk types really 802.1q and ISL. You can also have these trunks dynamically negotiate or fixed on.

With VTP you can VTP server/client mode, transparent mode or no VTP mode at all.

Jon

jamesgonzo · ‎10-06-2008

1.) Thanks

2.) So by default the trunk port is in native vlan 1 as a vlan isn't assigned to it? If it is not tagged how can it be used on the trunk?

3.) How would I set up transparent mode?

4.) what is more commonly used 802.1q or ISL?

Thanks

Jon Marshall · ‎10-06-2008

1) No problem :)

2) Not sure i understand. Vlan 1 by default is the untagged native vlan. All other vlans on the trunk are tagged with their respective vlan ID. You can change the native vlan if you want.

3) On the switch

switch(config)# vtp mode transparent

4) 802.1q

Jon

Edison Ortiz · ‎10-06-2008

2.) So by default the trunk port is in native vlan 1 as a vlan isn't assigned to it? If it is not tagged how can it be used on the trunk?

The native Vlan is often used as a 'fall-back' Vlan if the device attached to that port does not support trunk, for instance a workstation.

You often see in some VoIP implementations where a trunk configuration is required for the IP-Phone which is daisy-chained to a workstation. This port can also service a regular workstation and it will use its Native Vlan as the 'Access-Vlan' for that connection.

HTH,

__

Edison.