Routers could be easily confused with switches or bridges, since some of their functions intersect. However, router communicate with the outside world (outside the network) which other devices are not capable of. Routers use network ID and operate at the network layer. Without routers it is impossible to send signal outside of the WAN.
Network ID and device ID both are combined into 32 bit long IP address. It is used for identification for the networks that use TCP/IP protocol. However there are different protocols like AppleTalk and IPX/SPX which are also routable.
Routers are oversimplified computers that are created with a sole purpose of delivering data packets from point A to point B. After data packet is received by router, it examines its destination information. The similar way as postal worker processing the mail, router has no access to the data inside the packet. After reading the destination address, router tries to determine fastest way to deliver the data to the recipient. Router contains routing tables which have all the necessary information to do that. These tables contain addresses and routes of delivery for data. If the router contains no information about recipient that it should send information to, it would inform the sender that delivery is not possible. If the router has information about recipient, it will deliver data or send it to next node which will send it further.
Routing decision for the data packet is done by the number of devices that use TCP/IP protocol in the network. Devices containing routing tables are able to find optimal path for the data.
Internal configuration of the routers is complicated and often requires proper certification by staff. We at AD-net are happy to assist you to overcome any issues you may come up with while using our equipment.