So I was understanding how inter-vlan routing happens using L3 switches (using the c3650 series) and came across something I couldn't find solid information on (or I don't know how to search for it). I was trying to do inter vlan routing between 3 switches. I created two SVIs to represent hosts and assigned them to VLAN 10 and 20 respectively. Without using the ip-routing command, I was able to ping SVIs belonging to different VLANs on different switches! All the switches were configured with VLAN 10 and 20 but what I didn't understand is how they were able to contact each other without the routing functionality enabled!
When we do RoaS, we have a router that does the routing function for us. But when it comes to an L3 switch, without enabling ip routing, how is it routing between the two SVIs? They're part of two different subnets!
I had heard that this phenomenon was only because SVIs are internal to the switch and hence there's no egress ingress traffic to need routing. On enabling debugging, I came across the term "LOCAL CLUSTER" and on searching about it, couldn't exactly find the solution I was looking for but I feel it might have something to do with this.
Any help would be much appreciated! Thanks in advance.