What You Should Know about Wireless WANs to Get a Networking Job - dummies

What You Should Know about Wireless WANs to Get a Networking Job

By Peter H. Gregory, Bill Hughes

Wireless WANs is essential knowledge for anyone hoping to get a networking job. Unlike wired service, wireless WAN access is available from many sources. The largest providers these days are cellular carriers. In addition, you can get your own microwave connection, satellite service, or private radio.

Going beyond texting on a cellphone

Not too long ago, cellular carriers realized that you could send data over their cellular networks. A few pioneering souls back in the mid-1990s connected special modems to their cellphones. The cellular carriers found that these customers used three or four times as much airtime, never called for customer service, and did not switch their service to save a few pennies.

As a result, cellular carriers went on a competitive binge to offer faster service in more places. These new offerings were great because we all received faster service at a lower cost. However, all these new names and claims were confusing, with all kinds of acronyms and marketing hyperbole.

The different cellular companies would all claim that their network was the best and the fastest. They would claim that their network was 1G, or 2G, or 3G. They never explained that 1G meant first generation, 2G meant second generation, and so on.

They were also comparing apples and oranges. Sprint, Verizon, and US Cellular use a digital technology for voice called CDMA. AT&T and T-Mobile use a digital technology for voice call GSM. 2G technology on CDMA is different than the 2G technology on GSM.

Moreover, whether the user is stationary, moving (as in walking), or driving makes a significant difference in data throughput. This factor was conveniently left out of the advertising copy. The Radio Section of the International Telecommunications Union (ITU) says that 3G should be up to 7.2 Mbps. They also said that 4G should be 1Gbps when stationary and 100Mbps when moving.

However, ITU does not officially own the term 4G, plus other requirements are not met. The bottom line is that cellular carriers can call whatever they want 3G or 4G and get away with it.

What is more important is whether or not you are in coverage. The concept of coverage is easy to understand when dealing with voice service but less obvious when you are talking about data.

Ignore whatever G the carrier is telling you they have and pay attention to their coverage.

Cooking with a microwave connection

No, this isn’t a reference to cooking in the literal sense. This is a discussion about microwave communications. If you have to connect to buildings across the street, you may be surprised how economical and convenient it is to set up a point-to-point microwave system. As long as you have line-of-sight from point A to point B, many companies will put up microwave systems that are more economical over the long run than buying ongoing service from a LEC or CLEC.

Microwave is a telecommunications technology that has been used since World War II. Telecommunications companies have provided service between switching center offices for decades. About one third of the millions of miles of lines managed by LECs are provided by microwave.

Point-to-point microwave communication has several gotchas. First, you have to have line of sight from point A to point B. Next, you need access to the roof, which can be complicated if you are a renter, or you need to “shoot” through windows, which reduces your range. If these are not big issues, you should consider microwave as an alternative or a complement to service from the LEC.

Another option for microwave communication is WiMAX (Worldwide Interoperability for Microwave Access), which is a technology used by the Clearwire network.

WiMAX is a wireless telecom standard that provides data rates up to 40Mbps for mobile stations and 1Gbps for fixed stations. WiMAX was developed to be a wireless alternative to DSL and DOCSIS.

Clearwire offer service in 17 markets in the United States and is targeted to small businesses and fixed wireless applications.

Circling around satellite communications

Satellite communications seemed exotic at one time. These days, almost anyone can acquire television service from DirecTV or Dish Network and install his or her own satellite receiver.

The data-only equivalent satellite TV service is called VSAT, or Very Small Aperture Terminal. Depending on the service you acquire, you can get uploads and downloads in the narrowband or broadband range.

There are a few important considerations when considering VSAT service. First, VSAT terminals have a longer latency than ground-based systems. Regardless of the volume of data and the rate of speed on the network, it takes a few seconds to get everything flowing. This factor is not an issue for some applications and a showstopper for others. If you want to send and receive large files, the delay is not a problem. If you’re doing lots of short transactions, the delays may drive users batty.

Another consideration is that VSATs are good at sending large files to a remote site, but are much more limited sending files from the remote site back up to the satellite. Again, slow upload speed is either a big problem or no problem depending on your circumstances.

VSAT excels in providing a backup to landlines. Landline service can fail, for example, when a backhoe rips up communications cables. A backhoe can’t rip up communications between a satellite and the ground station antennae.