Core, Distribution, Access Layer 3 Question

[Ryan Heseltine]

Hi all,

We've currently got a network design that involves only a Core and Access layer, both with layer 3 switches, with VLANs that span over mutliple switches over both layers.

As we're coming to the point of running out of space within the Core I'm looking to assess this fundamental network design and look at the possibility of adding in a distribution layer, however, I'm concerned with the current spread of VLANs accross the layers that this might cause some performance issues.

Therefore, my question would be in line with Ciscos recommendations for network design would it be best to create seperate VLANs so that they aren't spreading over multiple layers of the design and instead communicating at L3 rather than L2 and is it still best to connect these multi-layer switches together with VLAN trunking?

Regards,

Ryan               

[Reza Sharifi · Accepted solution]

Hi Ryan,

If you are adding more layers to your design, try to stay away from using layer-2.  If you terminate your vlans on the distro switches, can can use layer-3 routed links to the core switches.  If you use layer-2, you would need to worry about spanning tree.

HTH

[Ryan Heseltine]

Hi,

To do this would I want to to be creating an SVI vlan on either end of the link and then creating a .1Q trunk which can only carry both of those vlans, or is there a better way of doing this?

Regards,

Ryan