The type of network technology you use will usually be determined by your router, which is typically provided by your ISP as part of a broadband internet package. But do you know what a router really does and what to look for?

A router is a bit like a switch in that it forwards traffic around a network. However, there are major differences in how both devices do that. For example, a switch is designed solely to forward traffic on a local network; it only has connections to the local network and if it gets a chunk of data (a 'packet') addressed to a system on a 'foreign' network it won't, by itself, be able to do anything with it.

A router, by contrast, will have connections to multiple networks. Most home routers will be connected to both the local network and the internet, via an ADSL or cable broadband service (nowadays some routers can even support 3G mobile broadband connections). Routers can direct or 'route' traffic differently, depending on how the packets are addressed. Packets addressed to other local devices, for example, are kept on the local network while those addressed to 'foreign' networks will be routed out onto the internet to be, possibly, further forwarded to their ultimate destinations by other routers. ln simple terms, the internet is just a huge collection of routers enabling connections between millions of local networks such as your own home network.

Don't worry too much about how a router 'learns' how to direct network traffic. All you need to know is that on most networks the router is, effectively, a shared gateway enabling all the devices on the Lan to connect to the rest of the world via a single internet connection. Every bit of traffic in and out passes through it, so a router is a good place for other common network tools and technologies to be sited.
Most internet routers, for example, will have a firewall built in, plus a variety of other optional add-ons such as anti-virus scanners or content filters to protect Lan users from common internet threats. A router makes a good home for DHCP (more about this later) and virtual private network (VPN) servers, to enable remote users to connect to the Lan over encrypted internet 'tunnels'. You can get routers with Voice over IP (VoIP) gateways built in, to let you route phone calls over the internet, and so on. All in all then, routers are important bits of kit on any home network.