Question on Trunk Links using the same VLAN ID's in Cisco7513

[tselvan]

Hi All,

Can we use the same VLAN ID's on two different subinterfaces to setup a trunk link between Cat6500 & Cisco7513.

Example:

int fa 3/1/0.28

encap dot1q 28

int fa 4/1/0.29

encap dot1q 28

If not are there any other ways to setup the trunk to carry the traffic of the same Vlans.

Thanks in Advance,

Beno

[jackyoung]

Yes, you can include the same VLAN in different trunks.

[tselvan]

Thanks Jack for your quick reply..

But can both the trunks carry the traffic of the same Vlans.How will this work? Sorry that am not very sure about this.Also I will be using two fastethernet links to create the trunk in cisco 7513 to cat6500.

I am not very sure whether cisco cli allows you to enter same Vlan id's in two different subinterfaces.If possible could you send me some config sample links?

Really sorry if my question is very silly.

Tks

[jackyoung]

you're welcome. You can treat the VLAN as logical interface in the switch / router that you can connect to other deviced w/ multiple interfaces. However, in this case, if you enable same VLAN in both trunks to the same remote device directly. it will create the looping and spanning tree will take effect to block one port somewhere in the loop.

Therefore, if you want to enable multiple connections between two devices with same VLANs. You can enable the Etherchannel in these connection that there is only one logical (port-channel) interface and enable the trunk in this interface then no looping.

Hope this helps.