Will configuring SSH on a 2960 or 3560 switch using telnet deny access to hosts on the network? Will the above bring down the network? Thanks.
You can configure ssh and telnet access to a switch if that is what you want to do. Or once you have configured ssh you can disable telnet access so only ssh can be used to access the switch.
Configuring ssh on your switch will have no affect on hosts who are connected to that switch accessing other hosts/servers and it will not bring your network down. SSH is used merely to log onto the switch itself.