Routed Access and Virtual Switch Distribution Layer


(Alexander F) #1

Hi all,

I am studying a lot about Cisco’s designs and need to refresh my knowledge daily, especially with Datacenter Technologies and Edge Connections. I find it quite hard to keep up with all hardware and Technology Cisco offers. At the Moment ACI is a real time taker for me. But my question is about Campus Design and i hope to get a complete understanding someday:
For MY preferred Campus Design i am thinking a lot about Routed Access, but i have still Problems in understanding the principles when having a Routed Access:

  1. It is an SVI on the Access Switch and a “no switchport” Uplink??
  2. How does it integrate then with VSS/Stackwise Virtual on the Distribution Layer as I cant have routed Uplink with Multichassis EtherChannel??
    Or is it an SVI in the Access Layer, then a MEC trunk to VSS(or StackWise Virtual or VPC) Distribution Layer an then a Routing process between the SVI’s??

I hope we can start a mind opening discussion.


(Lazaros Agapides) #2

Hello Alexander

If you design a network that includes routing at the access layer, then yes, you will have an SVI on the access switch that will act as the default gateway and will route between local subnets. The Uplink to the distribution layer can be a routed port, or it can be a Layer 2 port on a particular VLAN used for the interconnection between the particular Access and Distribution switches. Both would be acceptable. The second would probably be a little more flexible because it can allow you to have multiple Layer 2 links between the access layer and the distribution layer with only a single SVI port on both ends rather than multiple links each requiring its own subnet in the case of routed ports. This would also be easier to implement etherchannel uplinks including multichassis Etherchannel. You make this same point when you say

Such a configuration would be compatible with the MEC trunk as well as VSS or switch stacking as well at the distribution layer.

I hope this has been helpful!

Laz