Where are people doing layer 3 in campus lan

[carl_townshend]

Hi all

just a quick question, where are people putting the gateways these days for vlans? Is it still at the collapsed core or distribution layer?

what about layer 3 to the edge? Many people doing that?

[Joseph W. Doherty · Accepted solution]

In the environments I've worked in, much depended on what the edge devices were.  If large chassis based L3 switches, then routed on them.  If small switches, like 3Ks, even when stacked, often used them only as L2.

Often the deciding factor was whether the device would be doing mostly just north-south traffic, or also east-west.

Also in the case of L2 edges (again L3 capable), they often would have dual uplinks, to different physical upstream devices, but those devices would be a stack, VSS or vPC.  So no STP blockage of an uplink.  I.e. no real advantage, in these cases, for edge routing.

Further, edge routing, costs more for initial licensing and maintenance.  Again, needless expense if you don't obtain any advantage using it.

[balaji.bandi]

It depends on your design, If all Layer 2 , your Core should have Layer 3 interface configured.

if Layer 3 setup at Access Level - then Layer 3 VLAN resides at Access Layer with IGP with Core.