Creating a VLAN for interconnecting switches

thiyagarajankalaiselvan · ‎06-01-2010

Hi All,

May be I a am silly to aks this questions. Why we are creating a VLAN in some cases while interconnecting switches.

For Ex,Switch1 <--------> Switch 2 , We have created a VLAN and assighned the interconnecting ports to that VLAN.

As per understanding we need to trunk while interconnecting switches.

Why are we creating a VLAN for the interconnecting ports?

does is it use forward L3 traffic?

I am very curious to know about this?

Any information regarding this is appreciable.

Regards,

Thiyagarajan

Giuseppe Larosa · ‎06-01-2010

Hello Thiyagarajan,

creation of a Vlan to be used for routing traffic is a possible reason

another possible use is at the border between two networks managed by different entities and you don't want to share all your Vlans with them as it would happen with a L2 trunk + for example VTP configuration.

if you want to keep separated two VTP domains you need to use access links not L2 trunks to connect the two border switches.

Hope to help

Giuseppe

Ganesh Hariharan · ‎06-01-2010

Hi All,

May be I a am silly to aks this questions. Why we are creating a VLAN in some cases while interconnecting switches.

For Ex,Switch1 <--------> Switch 2 , We have created a VLAN and assighned the interconnecting ports to that VLAN.

As per understanding we need to trunk while interconnecting switches.

Why are we creating a VLAN for the interconnecting ports?

does is it use forward L3 traffic?

I am very curious to know about this?

Any information regarding this is appreciable.

Regards,

Thiyagarajan

Hi Thiyagarajan,

That depends on what type of connectivty are you using is it acces port or trunk port between the switches, If trunk then we are extending the vlans from one switch to other ,If access then we are just extending the vlan boundary and ofcoarse routing for vlan will be done as per the setup where your gateway router present.

Hope to Help !!

Ganesh.H

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