SD-Access Fabric Devices and Extension Nodes

[UncleJP]

I am studying for the ENCOR exam, and I am working on SD-Access. I understand that (correct me if I'm wrong) the physical layer of the SD-Access fabric consists of the network devices. Here is the excerpt that confuses me:

"Cisco access layer switches that do not actively participate in the SD-Access fabric but that are part of it because of automation are referred to as SD-Access extension nodes."

1. How does automation cause a switch to not participate in the SD-Access fabric? 

2. Can't a switch that doesn't participate in SD-Access fabric be a part of the fabric even without automation?

There is a possibility that there is a discrepancy in my understanding, because I am just learning about this topic. If you find that I would benefit from a particular YouTube video to clear up any misconceptions, I would be very grateful if you shared it.

Any input is appreciated. Posts will be rated and mark where due.

[Scott Hodgdon · Accepted solution]

UncleJP,

1. That statement is incorrect. It should read "are referred to as SD-Access Intermediate Nodes". There are Extended Nodes, but these are usually IE Switches and Cat 3560CX in most designs. If you want to know which devices have been approved for which roles, please see https://www.cisco.com/c/en/us/solutions/enterprise-networks/software-defined-access/compatibility-matrix.html . This lists all of the tested and supported software / hardware combinations, and on the left side of the screen it is organized by SD-Access role. LAN Automation does not determine if a switch is part of the fabric or not. LAN Automation builds the Underlay, and the the switches that will be part of the fabric are chosen using a different workflow.

2. I think the phrase "participate in the SD-Access Fabric" is a bit vague (not your fault for sure). We have Border Nodes, Edge Nodes, Control Plane Nodes, Wireless Controllers and Access Points (as far as networking equipment) that plays specific roles in and SD-Access fabric. We then could have Intermediate Nodes, which are nodes that just route traffic between these other nodes. Intermediate Nodes usually exist in 3-Tier (or more) SD-Access networks, so if you have just a 2-Tier network you would most likely not have these.

I would l recommend the session BRKCRS-2810 inn the On-Demand Library at ciscolive.com (you can create a free account if you do not yet have one) , as these nodes are covered in more detail there. If you have further questions after viewing this session, bring back any questions to thee Community and we can address them. I like to say : when one person asks, everybody learns :-) .

Cheers,

Scott Hodgdon

Senior Technical Marketing Engineer

Enterprise Networking Group

[UncleJP]

That was an excellent response. Thank you for your help, Scott!