Two switches, two VLANs

Aaron.Stones · November 2006

Hi

My question is:

How to cable two switches -2950, with two vlans and how to configure trunking and on what ports? Do I have to loop switches?

Replays very welcome. Thanks.

Example:

Connect switch1 port fa0/24 and switch2 port fa 0/1 with crossover cable.
Configure switch2 port fa 0/1 with command - switchport mode trunk.
Will this work?

Webmaster · November 2006

You only need to use one cable (that's the whole idea of trunking) and you actually don't need to configure them. The interfaces default to 'dynamic desirable' (ie. run show interface trunk module 0 or show interface switchport module 0) which means the switches will use DTP to actively try to convert the link into trunk. But yes, you can use the switchport mode trunk command to explicitely configure it as a trunk. You will also want to configure a VTP domain name.

Click here for more info.

Aaron.Stones · November 2006

Thanks for info and the link.

Paul Boz · November 2006

Is it good practice to manually configure trunked ports using the switchport trunk command? I've always done that for the sake of having it "propperly set up" but I know it works either way.

Humper · November 2006

Paul Boz wrote:

Is it good practice to manually configure trunked ports using the switchport trunk command? I've always done that for the sake of having it "propperly set up" but I know it works either way.

I have always forced my trunks

If you want them to always be trunks there is no reason (IMO) to have dynamic desirable.

command structure to trunk unconditionally and to disable DTP

switchport mode trunk
switchport trunk encapsulation dot1q/isl <

not needed on 2950 but used on 3550
switchport nonegotiate

then there are commands for the native vlan and which vlans you'd like to cross the trunk

Two switches, two VLANs

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