f I have two cisco routers connected over two switches (router1 - switch1 - switch2 - router2), is there a kind of keepalive mechanism or somethink like it, that would give me possibility to SEE on routers if link between switch1 and switch2 is broken.
If you are looking at strictly layer 2 solutions then I do not believe that there is any layer 2 keepalive that can tell the routers that the link between the switches is not working. If you will look at layer 3 solutions then there are several possibilities. As BVS mentions a dynamic routing protocol running over that link would detect failures. Or you could configure Object Tracking to track reachability of the remote interface.
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...