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Why Do We Need Inter-Vlan Communication?

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January 1, 2016

Let me explain, i know vlans separate broadcast domains and one of the reasons for using it was to separate communications between devices in different vlans, if so then why do we need inter-vlan communications, doesn't that contradict the use of vlans? Not really, Generally when they are talking about inter-vlan routing, they are talking layer 3. When talking about broadcast domains generally you are talking layer 2. So say for example, you have an office floor, and you dedicated that floor to a specific Vlan. Any Intra-Vlan communication is going to be down with layer 2(Arp requests etc), However, let's say you have a separate floor that houses your web-server, SAN storage etc, these are going to be on a separate Vlan, and most likely people on the office floor are going to need to communicate with the web-server so they need to know how to get there...i.e from one Vlan to Another. However, they don't need to be in the same Vlan as the office floor. For theoretical purposes you can think of Vlans as two separate physical networks, we often have to communicate to devices on other networks, but it requires Layer 3 routing to accomplish this, the same can be said of Vlans. Thank you for you reply, it is much more clear right now, i was stuck with that doubt for 2 days without finding an answer to it. Glad to be of assistance, there are many good free course out there. One I partial too is the one available from Juniper(It's free), it's condensed to about 4 hours and IMO is one of the best out there for a 'high level' view. You may have to create an account, but it's free and easy.\_activity\_info.aspx?id=769 Dear all My Question is very simple :-After inter-vlan set up can we stop the broadcast(LOOP) of one VLAN to going in another vlan. If we do intervlan than broadcast of one vlan reached in all vlan as all vlan in inter-vlan. I have seen live scenario outage of whole network due to broadcast in one vlan?????. Is this due to Intervlan Is this due to all vlan in same subnet that is /26.
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