Hai,

In my office we have 50 systems. We have taken two internet connections from different isps. Both speed are 4 mbps. For backup only we have taken another one. Our lan will be in workgroup. The question is can I keep two connections at a time to switch. Switches are unmanageable switches. Does it works. I want to keep two connections. Or I have to configure. Please help me.

Multiple gateway devices, like routers, can be attached to the same switch. However, without another device such as a load balancer monitoring the two connections or a mechanism in the router(s) terminating the two connections to detect a failed connection and adjust their routing table, fail-over to the backup connection would need to be done manually by changing the routes in the router's configuration. For automatic fail-over, configuring Border Gateway Protocol (BGP) on the gateway router(s) is one solution in this scenario but it requires ISP coordination and is not a trivial endeavor.

Post the model info of the devices terminating your connections and you may get a less general answer.