In a previous blog post, I demonstrated the Fabric Attach capability in my lab. Now, let’s explore the Auto-Sense capability. I previously explained what Auto-Sense is: essentially, it allows a switch port to be configured automatically based on the connected devices.
On Fabric Engine, Auto-Sense is enabled by default:
interface GigabitEthernet x/x
auto-sense enable
exit
vlan create 4048 name "onboarding-vlan" type pvlan-mstprstp 0 secondary 4049
vlan i-sid 4048 15999999
auto-sense onboarding i-sid 15999999
The Auto-Sense capability is straightforward and easy to configure. You just need to set an I-SID for specific services like data, voice, and Fabric Attach:
auto-sense data i-sid <1-15999999>
auto-sense voice i-sid <1-15999999>
auto-sense fa camera/ovs/wap-type1 i-sid <1-15999999>
If you have a NAC solution, only Auto-Sense for Fabric Attach should be configured; the NAC will handle the rest during the authorization process.
Let’s check the Auto-Sense interface states using the command show interfaces gig auto-sens gig
And the port configurations. Here we have the defaults—no configuration has been done.
I connected a Fabric Engine switch to interface 1/1, and the Auto-Sense status shows NNI-ISIS-UP
This indicates that the fabric switch was connected and an IS-IS adjacency was established. We can confirm this with the command show isis adj
To interface 1/2, I connected a switch with Switch Engine and Fabric Attach enabled. This time, the Auto-Sense state is FA-PROXY-NOAUTH
We can confirm that Fabric Attach was enabled using the command show fa elements
For port 1/3, I connected a PC. The port state is UNI, and since a RADIUS server was configured, 802.1X should be enabled automatically. Let’s confirm it with show eapol sessions eap
And the show i-sid command will confirm what was assigned during the authorization process. The output u:1/3 means that untagged traffic was mapped to I-SID 2100051.
To summarize what was shown in my lab: using the Auto-Sense capability, you don’t have to worry about port configurations. Ports can be automatically configured based on the connected devices.
In conclusion, with Fabric Connect, Fabric Attach, Auto-Sense, and a NAC system, you can have a network that self-provisions and adapts based on your needs. Manual configuration is minimal. In my opinion, this whole solution is a game-changer compared to the traditional approach. Importantly, it is quite simple, not complicated, and based on open protocols.