Redefining the Endpoint--Wireless Broadband Routers

Things used to be simple with wide-area wireless networks. The network endpoints were mobile telephones or modems. The modems were inside PDAs or laptops. The endpoints were basically you and me--people. But that's changing, with companies like Netgear, which last week announced a wireless broadband router for Flash OFDM. Netgear's router has a wide-area connection using Flarion's (now owned by Qualcomm) Flash OFDM technology and local connections using Wi-Fi and Ethernet. Okay, so there are no Flash OFDM networks in the United States. But Cingular and Sprint have offers in this area, and Verizon is not far behind. The endpoint is no longer a person; it's a network. And just as we were going to press, we saw D-Link's August 30 announcement of its Wireless 3G Mobile Router.

The general idea is to terminate the wireless WAN connection at a device that routes to a network. I got a nice taste of this recently at an industry association meeting where an enterprising network engineer had a UMTS card in his laptop and distributed his Internet connection over Wi-Fi to willing recipients in the meeting. About a dozen of us enjoyed this ad hoc service, and it worked just fine. In this case, Microsoft Windows in the laptop was doing the routing, with each of us using a separate IP address provisioned from the laptop.

So should we all start using our UMTS (and forthcoming HSDPA) or EV-DO connections as an alternative to T1s or DSL connections and share that connection with multiple endpoints? However tempting that may sound for some scenarios, it's not the best application of the router technology. Wireless broadband speeds are on average lower than wired connections, latency is higher and, most importantly, monthly costs are higher. Furthermore, the unlimited usage service plans are likely to prohibit this type of usage. The application that does make a lot of sense, however, is backup connectivity, particularly for mission-critical situations. Rather than having a redundant wireline connection, you can use the wide-area wireless connection for backup. For applications such as metering and retail point-of-sale that don't transmit much data, the wireless connection might even be the primary application.

Cingular supports this type of connectivity with its Wireless WAN Connectivity service, which is accompanied by a router from Digi called Digi Connect WAN GSM. This router is a compact device that supports GPRS and EDGE. Sprint's offer in this area is its PCS Data Link service, which originally supports 1XRTT, and will be an obvious candidate for Sprint's forthcoming EV-DO service. Verizon does not yet have a formal plan. A number of routers support EV-DO; for example, the Kyocera KR1 router with Wi-Fi and the TopGlobal routers. Junxion makes a router that allows you to insert PC Card format modem cards and supposedly support EDGE, 1xRTT and EV-DO. The D-Link router also accepts modem cards for all the major 3G networks. Omniwav has an EV-DO router designed to be installed in vehicles. Every major router vendor is likely to follow suit. This market area is in its early days, but clearly coming alive.

If you're thinking about how to take advantage of wireless WAN network-to-network connectivity, here are some considerations. First and foremost, make sure the service plans allow this kind of usage. Then make sure the wireless WAN connection has the horsepower for your application. Realize that wireless speeds vary according to signal quality and network loading, so test the application in both best-case and worst-case scenarios. Then investigate pricing. Even though operators have unlimited usage plans, these are designed for end users and are not intended for transmitting large numbers of gigabytes of data every month.As impressive as the capabilities are of new wireless networking technologies, I have previously commented on their relatively low capacity, meaning it doesn't take very many endpoints communicating continuously to swamp the capacity of the local cell site. Operators are very sensitive to this, and it is reflected in their pricing plans. For instance, Cingular offers usage based plans from 5 MB for $19.99 per month to 50 MB for $49.99 per month and also allows multiple devices to be pooled together to determine total monthly usage, which can be useful as it can be hard to predict the amount of traffic at any one node. Sprint's pricing is at a similar level, with 40 MB costing $40 per month. You'll also need to estimate how much traffic may go over your backup connection so you don't get nailed with overage charges.

You'll still have to do your network planning, such as designing routing approaches. The Digi product, for example, supports GRE encapsulation, which allows the remote network to have IP addresses assigned via the home network.

With the higher networking speeds of technologies such as EV-DO, HSDPA, Flash OFDM and WiMAX, the wireless broadband router market makes a lot of sense, and it is likely to become one more tool in your networking toolkit.