Looking for a core (other switches and devices are connected to this switch) switch at our company.

I wonder if splitting LAN into VLANS and then gaining access to some computers to that network is possible without layer 3 switch?

And what's possible with layer 3 switch and not possible with layer 2 ? What if we want to connect 2 networks over internet?

  • Please explain what you want/need to do better. Bridging (layer 2) will give you a single broadcast domain, allowing broadcast-based protocols to work, but will be less efficient if you have slow inter-zone links. Routing (layer 3) will be more efficient to constrain traffic over long links, but will bring higher latency, a split broadcast domain, and a split address space. – b0fh Jul 20 '10 at 12:18
  • I need a core switch for organization where we would like to split data and video networks, but making some devices access to video network. I thought is it possible without routing? – Janis Veinbergs Jul 20 '10 at 12:37

A VLAN is, essentially, a virtual switch. If you have VLANs with different IP netblocks on them, you'll need a Layer 3 device to provide connectivity between the VLANs. If you have them all on the same IP range, you'll need Layer 2 connectivity between the VLANs and the VLAN partitioning is pointless.

Having VLANs with different subnets and no routing between them would work on L2 switches, as long as you have VLAN trunks between them, but in that scenario, you're segregating the different VLANs and making it impossible to communicate between them.

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