Ask the Wi-Fi Guru About Wi-Fi, 4G and Wireless Printing

By Aaron Weiss

April 19, 2010

Our monthly Q&A series offers advice to those seeking help with home or small business WLANs. This month our guru looks into his crystal ball and considers the future of Wi-Fi in the 4G era before helping a reader work out some problems with a wireless printer and DD-WRT.

Our monthly Q&A series offers advice to those seeking help with home or small business WLANs. This month our guru looks into his crystal ball and considers the future of Wi-Fi in the 4G era before helping a reader work out some problems with a wireless printer and DD-WRT.

Would you like to ask the guru a question? Write the editor.


Our focus here is normally on Wi-Fi wireless networking, but chances are if you live in the modern world and already use wireless devices, your experience also intersects with cellular technologies, often called 2G, 3G, and 4G. Today, most smart phones -- iPhone, Droid, Blackberry, and many others -- use so-called 3G cellular wireless. (Many also support Wi-Fi when in range of a wireless router.) Although cellular wireless and Wi-Fi are different technologies, they are increasingly intertwined in real-world use. As 4G begins making inroads in 2010, it is interesting to consider how cellular and Wi-Fi will impact each other.

The "G" in 3G/4G stands for "generation", meaning that these are the third and fourth generation cellular data networks, respectively. The 3G networks that most of us use today with smartphones offer speeds between approximately 0.5mbps to 2mbps. Actual performance at any moment can vary widely depending on how crowded the nearest cell tower is, not to mention network management practices in place by the cell provider.

In the U.S., Sprint has been the first carrier to deploy a 4G network, using WiMAX. Verizon and other carriers plan to follow suit with their own 4G using LTE. Although LTE and WiMAX are different technologies, they are said to deliver speeds about 4x faster than 3G, between 2-8mbps on average. Theoretically, this pushes 4G into competitive range with many terrestrial broadband products, including DSL and low-end cable networks.

The key word here being "theoretically." Whether real-world 4G performance will maintain those speeds remains to be seen, particularly if the service becomes popular. Unlike terrestrial broadband, cellular networks currently impose relatively low usage caps, often 5GB/month for the popular data plans. With a 4G connection, you could chew through 5GB in a matter of days, let alone a full month.

Enter Wi-Fi. Wireless networking increasingly plays two roles in the world of cellular communication. Most smart phones support Wi-Fi in addition to 3G/4G. This means that when you are within range of a Wi-Fi network, the phone can send and receive data without eating bytes from your monthly quota. (Terrestrial broadband connections often do not have usage quotas or, where they do, are many times larger than cellular quotas.)

In addition, Wi-Fi is now being used to share a 3G/4G network, effectively turning mobile cellular devices into wireless hotspots. Using a device like the Novatel MiFi or the Sprint Overdrive, cellular subscribers can connect a handful of WiFi devices to one cellular data connection. Sprint's newest 4G phone, the HTC Evo, even has this feature built-in. Today, more of us carry multiple mobile devices—from laptops to netbooks to tablets like the iPad. Normally you would need a 3G/4G radio in each device, each with its own cellular data plan.

Because Wi-Fi is already widely supported in many kinds of devices (including printers and media players), a MiFi-like device greatly expands the reach of your cellular data plan. On the other hand, that can also be the problem: With low usage quotas, cellular subscribers can exceed their monthly allotments even more quickly with multiple devices sharing the same pipe.

All of which leads to an interesting question: if using WiFi to share cellular networks helps make 4G a "broadband everywhere" technology, will this in turn kill off today's public Wi-Fi hotspots? To take one example, if you're a bookstore or coffee shop, will there still be any value in offering a wireless hotspot when your customers are walking hotspots of their own? The same question might be raised about hotels, libraries and municipal Wi-Fi services.

Wi-Fi technology is effectively putting pressure on itself from both directions. Used as a back-up network to 3G/4G networks, Wi-Fi can relieve pressure on data plan quotas. But used to share a data plan among multiple devices, it will increase pressure on quotas—providing an incentive to use Wi-Fi rather than cellular data. Trying to predict the future is enough to make your head ache.

My DD-WRT Router Doesn't Work With My Networked Printer

Q: My Linksys WRT600N flashed with v24 DD-WRT does not work wirelessly with HP7410 all-in-one printer. The printer is able to make a connection, but I cannot ping the printer nor get other programs to recognize it. PC wired and laptop wireless work well. I have tried this with and without wireless security.

Printer IP 192.168.10.120
Router IP 192.168.10.1
DHCP begins at 192.168.10.100 - 192.168.10.249

There must be a DD-WRT setup that I have not figured out, but I have not found this info on DD-WRT forum or others. -- Tom

A: On the face of it, this doesn't sound like a problem related directly to DD-WRT. After all, this is a quite common setup and falls right into the wheelhouse of any wireless router regardless of firmware in use. There must be something else going on.

You've mentioned trying without wireless security. This was a good idea. Especially because, according to online sources, the HP 7410 supports only WEP, which has stymied people using (more secure) WPA/WPA2 security.

While researching this, it was not uncommon to see reports of wireless problems with this printer. So it's possible that your problem is a quirk with the HP 7410. Perhaps updating the drivers through the HP Web site are warranted. Of course, you can find online reports of problems with anything and everything, so this alone is not damning evidence.

Given the details provided, and the suspects already ruled out, my next guess will be your PC's firewall. J'accuse! Particularly if your PC is running the Windows firewall. It is possible that the firewall is blocking communications between the PC and printer, particularly if they occur over a non-standard port. I would (temporarily!) disable the Windows firewall and see if your printer and PC will get along any better.

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