Editing Multilayer switch (section)

===Layer-4 load balancer===
The router operates on the [[transport layer]] and makes decisions on where to send the packets.  Modern [[Load balancing (computing)|load balancing]] routers can use different rules to make decisions on where to route traffic.  This can be based on least load, or fastest [[Response time (technology)|response time]]s, or simply balancing requests out to multiple destinations providing the same services.  This is also a [[redundancy (engineering)|redundancy]] method, so if one machine is not up, the router will not send traffic to it.

The router may also have NAT capability with port and transaction awareness and performs a form of [[port translation]] for sending incoming packets to one or more machines that are hidden behind a single IP address.