How to replace equipment in the network without stopping work?

Question

Computer networks

Hello.
I have a network configured, how can I replace the pfsense server with minimal delay?
Just interested in replacing switches.
Network topology:

Topology.

There is a possibility to deploy an identical server.
Thank you.

Answer 1

In pfsense, there seemed to be CARP, which is an analogue of VRRP. There is one leading router and one spare, they constantly exchange information with each other, indicating that they are alive and working, if the main one stops sending information, the backup one takes over its functions.

Answer 2

I don’t know specifically about pfsense, but in the case of iron routers, normal people install another piece of iron, set up VRRP, calmly carry out work, first on one, and if necessary, on the other. Switches (aggregators) can be used in the same way, having thought of a reserve for the edge via xSTP

Answer 3

Well, if there is confidence in the preparation of a completely identical clone and the allowable downtime is commensurate with the time of plugging the connectors, then this is probably the most optimal method.