A router is a device that forwards data packets along networks. A router is connected to at least two networks, commonly two LANs or WANs or a LAN and its ISP's network. Routers are located at gateways, the places where two or more networks connect, and are the critical device that keeps data flowing between networks and keeps the networks connected to the Internet. When data is sent between locations on one network or from one network to a second network the data is always seen and directed to the correct location by the router. They accomplish his by using headers and forwarding tables to determine the best path for forwarding the data packets, and they use protocols such as ICMP to communicate with each other and configure the best route between any two hosts. The Internet itself is a global network connecting millions of computers and smaller networks — so you can see how crucial the role of a router is to our way of communicating and computing. Why Would I Need a Router? For most home users, they may want to set-up a LAN (local Area Network) or WLAN (wireless LAN) and connect all computers to the Internet without having to pay a full broadband subscription service to their ISP for each computer on the network. In many instances, an ISP will allow you to use a router and connect multiple computers to a single Internet connection and pay a nominal fee for each additional computer sharing the connection. This is when home users will want to look at smaller routers, often called broadband routers that enable two or more computers to share an Internet connection. Within a business or organization,  you may need to connect multiple computers to the Internet, but also want to connect multiple private networks — and these are the types of functions a router is designed for. Routers for Home & Small Business Not all routers are created equal since their job will differ slightly from network to network. Additionally, you may look at a piece of hardware and not even realize it is a router. What defines a router is not its shape, color, size or manufacturer, but its job function of routing data packets between computers. A cable modem which routes data between your PC and your ISP can be considered a router. In its most basic form, a router could simply be one of two computers running the Windows 98 (or higher) operating system connected together using ICS (Internet Connection Sharing).  In this scenario, the computer that is connected to the Internet is acting as the router for the second computer to obtain its Internet connection. Going a step up from ICS, we have a category of hardware routers that are used to perform the same basic task as ICS, albeit with more features and functions. Often called broadband or Internet connection sharing routers, these routers allow you to share one Internet connection between multiple computers. This image shows the flow of data to multiple computers sharing one high speed Internet connection. [Image Source] Broadband or ICS routers will look a bit different depending on the manufacturer or brand, but wired routers are generally a small box-shaped hardware device with ports on the front or back into which you plug each computer, along with a port to plug in your broadband modem. These connection ports allow the router to do its job of routing the data packets between each of the the computers and the data going to and from the Internet. Depending on the type of modem and Internet connection you have, you could also choose a router with phone or fax machine ports. A wired Ethernet broadband router will typically have a built-in Ethernet switch to allow for expansion. These routers also support NAT (network address translation), which allows all of your computers to share a single IP address on the Internet. Internet connection sharing routers will also provide users with much needed features such as an SPI firewall or serve as a a DHCP Server. Wireless broadband routers look much the same as a wired router, with the obvious exception of the antenna on top, and the lack of cable running from the PCs to the router when it is all set up. Creating a wireless network adds a bit more security concerns as opposed to wired networks, but wireless broadband routers do have extra levels of embedded security.  Along with the features found in wired routers, wireless routers also provide features relevant to wireless security such as Wi-Fi Protected Access (WPA) and wireless MAC address filtering. Additionally, most wireless routers can be configured for "invisible mode" so that your wireless network cannot be scanned by outside wireless clients.  Wireless routers will often include ports for Ethernet connections as well. For those unfamiliar with WiFi and how it works, it is important to note that choosing a wireless router may mean you need to beef up your Wi-Fi knowledge-base. After a wireless network is established, you may possibly need to spend more time on monitoring and security than one would with a wired LAN. Wired and wireless routers and the resulting network can claim pros and cons over each other, but they are somewhat equal overall in terms of function and performance. Both wired and wireless routers have high reliability and reasonably good security (without adding additional products). However —and this bears repeating — as we mentioned you may need to invest time in learning more about wireless security. Generally, going wired will be cheaper overall, but setting up the router and cabling in the computers is a bit more difficult than setting up the wireless network. Of course, mobility on a wired system is very limited while wireless offers outstanding mobility features. Are Routers Expensive? Below is a sample price comparison of routers and expected features as well as current pricing in U.S. dollars from online vendors found through PriceWatch in February 2005. ROUTER PORTS FEATURES PRICE NetGear RP614 Cable/DSL Router 4 Smart Wizard set-up, NAT firewall, up to 253 Network Users, Web site blocking, free network cable & stand. $40 NetGear VPN Firewall Router FR328S 8 Analog modem back-up, True Firewall (DoS protection and SPI), URL filtering, logging, reporting, NAT routing, VPN pass-through, high-speed CPU for faster throughput. $60 Linksys broadband Router with Phone Ports RT41P2-AT 4 2 voice ports for analog phones or faxes, Universal Plug-and-Play, NAT firewall,  supports DHCP $125 Linksys EtherFast Cable/DSL - BEFSR81 8 NAT firewall, supports QOS, DHCP, Universal Plug-and-Play, URL blocking, $70 D-Link Wireless Cable/DSL Router DI-624 4 802.11x, Indoors: Up to 328 feet (100 meters), WPA .Wi-Fi Protected Access, multichannel, AES encryption , compatible with all 2.4GHz devices $73 Today you can purchase a basic sub $70 broadband router that will enable you to share your broadband Internet connection with multiple computers in your home.  Before buying a router, however, you need to take into consideration the type of Internet connect you have, and how many ports you will need for individual computers, and of course, make the choice between wired or wireless.  It is always a good idea to purchase a router with extra ports in case you need to connect additional computers at a later date. You can also decide if your broadband router will be providing your PC security or if you're going to purchase a separate hardware firewall for protection. If you are thinking of purchasing a firewall in addition to a broadband router, you may want to check out our recent article on software and hardware firewalls.  DID YOU KNOW... Network research firm Dell'Oro Group predicts that worldwide revenue from routers will reach $10 billion by 2009, up from a forecast of about $7.1 billion for 2004. [Source] Hardware Central: Ultimate Guide to Networking: Part One — Bridges, Routers, and Switches Bridges and routers are devices used for linking different LANs or LAN segments together. There are many companies that have LANs at various offices across the world. Routers were originally developed to allow connection of remote LANs across a wide area network (WAN). Wireless Security Blackpaper While wireless networks have seen widespread adoption in the home user markets, widely reported and easily exploited holes in the standard security system have stunted wireless' deployment rate in enterprise environments. Linksys EtherFast Cable/DSL Router A step-by-step guide (with pictures) to setting up a Linksys EtherFast Cable/DSL Router. ZoneLabs: How to Set-up a Home network (PDF) An excellent guide for those considering a home network. Understanding WLAN Routers This Small Business Computing article discusses some of the many benefits to using wireless local area network routers. Understanding IP Addressing From Webopedia's Did You Know Section - Every computer that communicates over the Internet is assigned an IP address that uniquely identifies the device and distinguishes it from other computers on the Internet. Wireless Comes Home The latest home networking products promise to make linking your PCs together fast and affordable. But do they deliver? About's PC World tries out 12 new kits and select a Best Buy. Vangie 'Aurora' Beal Writer, www.Webopedia.com, Last updated: February 25, 2005

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