Question : Campus network design model.

Hi there,

i upload an image of a campus network model to http://img301.imageshack.us/my.php?image=campusnetworksdesignmodgi0.jpg for referencing.

I would like to ask in a cause of a campus network, where each building are in different vlan,
at my core layer of my network, if i use layer 3 switches what are the advantages and disadvantages. And if i use layer 2 switches are my core layer in this case what are the advantages and disadvantages?

Thanks.

Answer : Campus network design model.

With a layer 3 core, you can get equal-cost (and unequal-cost, if you use EIGRP and tune it) multipath routing.  With a layer 2 core, you have one link that's STP forwarding and all other parallel links are blocking due to STP.

With a layer 3 core, you can get very tight convergence (supposedly 200ms with EIGRP).  With a layer 2 core, you can get <1sec only if you use RSTP everywhere in the network (or at least everywhere it matters); otherwise, you're talking ~30-50sec convergence (maybe less with some of the Cisco features available).