Routers are small physical devices that join multiple networks together. It connects two or more network, typically two LANS or WANS or a LAN and its ISP's network. Thus, making all devices connected able to communicate with each other. Home networks typically use a wireless or wired Internet Protocol (IP) router, IP being the most common OSI network layer protocol. In here, an IP router such as a DSL or cable modem broadband router joins the home's local area network (LAN) to the wide-area network (WAN) of the Internet. Routers can also be used to filter traffic, either incoming or outgoing, based on IP addresses of senders and receivers.