L2 or L3 etherchannel between core switches?

tsrader · ‎04-21-2008

For a collapsed core design with multiple vlans spanning network, is L2 etherchannel the best way?

Would a multilayer design (core - dist - access) the best scenario for a L3 etherchannel? Does the L3 etherchannel then reside on the distro switches only or on BOTH distro and core?

Collin Clark · ‎04-22-2008

Let's assume you have a collapsed core. You have multiple vlans on each core switch and HSRP running between them. You should run a L2 EC between them. There is traffic between the VLANs and HSRP traffic that should cross that L2 channel. Will it work if it's layer 3? Yes, but the layer 2 traffic will go through your access switches. Same idea with the multilayer design. The time when a layer 3 link between the cores is optimal is when you have layer 3 at the access layer and your routing between your access layer and all other layers.