You would rely on spanning-tree to find the best path. If one of your interfaces goes down then it should send traffic to the next available interface. The downfall of ethernet circuits is that the protocol or interface typically doesn't go down when there is an issue. The switch or router will show up/up but actual issues exists and traffic is just being dropped from carrier issues. For that reason I like to setup IP SLA.
For the routing side just set both in the routing table and if you want an active/standby just weight one route higher.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...