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Published on The O'Reilly Network (http://www.oreillynet.com/) http://www.oreillynet.com/pub/a/wireless/2001/08/24/linksys.html See this if you're having trouble printing code examples Bridging 802.11 Networks with Linksys by Glenn Fleishman 08/24/2001 My downstairs office neighbor, a running coach named Tony, has an inquiring mind. He has heard me and my officemates wax sci-fi about wireless IEEE 802.11b networking. We somehow got him jonesing for it for when he expanded his coaching facilities to a second office in a building about 30 feet away, to which a wired extension to our shared network wasn't possible. The new office is embedded bunker-like into a concrete foundation below ground, as well as having thick walls in its above-ground portion. Otherwise, we could have hung his new computers as wireless devices on our existing 802.11b network. He also has some legacy equipment that needs an Ethernet hub, so couldn't go entirely wire free. We needed a solution that would allow us to extend our high-speed Internet service as well as the rest of the intranet in our existing building to Tony's new office 30 feet away. We wanted to bridge the gap wirelessly, making one seamless combination of wired and wireless networks. I'd been following discussions on the Bay Area Wireless User Group's (BAWUG) mailing list about the Linksys WAP11 access point (AP), and thought a pair of them might do the trick. At a street price (with manufacturer's rebate) of about $185, this AP supports a firmware upgrade that turns it into the bargain wireless bridge of the century. Comparable devices from vendors such as Cisco can run $800 or more. The Wireless Access Point Typically, an access point acts as a central hub, router, bridge to Ethernet, and server for dynamic host configuration protocol (DHCP) and network address translation (NAT), as well as other functions. The standard home gateways often have a wide-area network (WAN) Ethernet port (to connect to a DSL or cable modem) and one or more local area network (LAN) ports for the local network. The access point negotiates with wireless computers and other devices, hands out non-Internet-reachable NAT addresses via DHCP, and bridges traffic from the wireless LAN to the wired LAN and, through it, out to the Internet. (Home gateways with a WAN port bridge the traffic internally and send it all the broadband router.) The Linksys WAP11 with its single Ethernet port handles all this perfectly fine. It has minimal but sophisticated options for set up, and removable antennas with standard connectors so that you could hang a higher-gain antenna off the back - important for connecting networks over longer distances. Upgrading to build a bridge But the bridging firmware makes the WAP11 more than just cheap and functional. In bridging mode, you can connect two or more WAP11s together to pass wired Ethernet traffic among one another, creating a super-network. If you have multiple facilities nearby or with line of sight between them, you can avoid telephone company digital line charges, as well as recurring fees for separate Internet connections in each facility. Linksys's firmware upgrade 1.4f5, which supports bridging, was released, pulled and then re-released; the version number stayed the same. The two WAP11's I purchased for our multi-office installation came with release 1.3i installed; reports indi